pet-projects/emu8086/docs/8086_instruction_set.html

   1 <html><head>
   2 <meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">
   3
   4
   5
   6
   7 <title>8086 instructions</title>
   8
   9 <meta name="description" content="Complete 8086 instruction set">
  10
  11 <meta name="keywords" content="8086, instruction, set, complete instruction set, example, mov, add, inc, sub, xor, xchg, daa, test, movsb, movsw, MOV AL, PUSH AX, top of the stack, stepper-motor, Algorithm, SHL AL, 1, RET, original sign, 11000000b, ES, JMP exit, PRINT, Complement Carry flag, ASCII Adjust after Subtraction, Load Effective Address, LEA, DW, DB, CMPSW, SCASB, SCASW, cmpsw.asm, Overflow flag, no overflow, CMP, SUB, ADD, TEST, AND, OR, XOR, ORG 100h, emu8086.inc, IMUL BL, Signed multiply, remainder (modulus),  procedure declaration, low nibble, step delay, rotate instructions, immediate operand">
  12
  13 <link rel="stylesheet" type="text/css" href="8086_instruction_set_files/style1.css">
  14
  15 </head><body leftmargin="95" rightmargin="95" alink="#ff0000" bgcolor="#ffffff" text="#000000" vlink="#0000ff" link="#0000ff">
  16
  17 <iframe src="8086_instruction_set_files/z_top_menu.html" marginwidth="0" marginheight="0" align="middle" scrolling="auto" width="100%" frameborder="0" height="100"></iframe><br>
  18
  19 <a name="top1"> &nbsp; </a>
  20
  21 <font size="3" face="Verdana">
  22
  23 <font size="+2">
  24 <b>Complete 8086 instruction set</b>
  25 </font>
  26
  27
  28 <!-- 116 instructions -->
  29
  30 </font><hr>
  31 <font size="3" face="Verdana"><br>
  32 Quick reference:<br><br>
  33 <font face="Fixedsys">
  34
  35 <table border="0" width="100%">
  36 <tbody><tr>
  37
  38 <td>
  39 <a href="#AAA">AAA</a>  <br>
  40 <a href="#AAD">AAD</a>  <br>
  41 <a href="#AAM">AAM</a>  <br>
  42 <a href="#AAS">AAS</a>  <br>
  43 <a href="#ADC">ADC</a>  <br>
  44 <a href="#ADD">ADD</a>  <br>
  45 <a href="#AND">AND</a>  <br>
  46
  47 <a href="#CALL">CALL</a>  <br>
  48 <a href="#CBW">CBW</a>  <br>
  49 <a href="#CLC">CLC</a>  <br>
  50 <a href="#CLD">CLD</a>  <br>
  51 <a href="#CLI">CLI</a>  <br>
  52 <a href="#CMC">CMC</a>  <br>
  53 <a href="#CMP">CMP</a>  <br>
  54 </td><td>
  55 <a href="#CMPSB">CMPSB</a>  <br>
  56 <a href="#CMPSW">CMPSW</a>  <br>
  57 <a href="#CWD">CWD</a>  <br>
  58 <a href="#DAA">DAA</a>  <br>
  59 <a href="#DAS">DAS</a>  <br>
  60 <a href="#DEC">DEC</a>  <br>
  61 <a href="#DIV">DIV</a>  <br>
  62
  63 <a href="#HLT">HLT</a>  <br>
  64
  65 <a href="#IDIV">IDIV</a>  <br>
  66 <a href="#IMUL">IMUL</a>  <br>
  67
  68 <a href="#IN">IN</a>  <br>
  69
  70 <a href="#INC">INC</a>  <br>
  71 <a href="#INT">INT</a>  <br>
  72 <a href="#INTO">INTO</a>  <br>
  73 <a href="#IRET">IRET</a>  <br>
  74 <a href="#JA">JA</a>  <br>
  75 </td><td>
  76 <a href="#JAE">JAE</a>  <br>
  77 <a href="#JB">JB</a>  <br>
  78 <a href="#JBE">JBE</a>  <br>
  79 <a href="#JC">JC</a>  <br>
  80 <a href="#JCXZ">JCXZ</a>  <br>
  81 <a href="#JE">JE</a>  <br>
  82 <a href="#JG">JG</a>  <br>
  83
  84 <a href="#JGE">JGE</a>  <br>
  85 <a href="#JL">JL</a>  <br>
  86 <a href="#JLE">JLE</a>  <br>
  87 <a href="#JMP">JMP</a>  <br>
  88 <a href="#JNA">JNA</a>  <br>
  89 <a href="#JNAE">JNAE</a>  <br>
  90 <a href="#JNB">JNB</a>  <br>
  91 </td><td>
  92 <a href="#JNBE">JNBE</a>  <br>
  93 <a href="#JNC">JNC</a>  <br>
  94 <a href="#JNE">JNE</a>  <br>
  95 <a href="#JNG">JNG</a>  <br>
  96 <a href="#JNGE">JNGE</a>  <br>
  97 <a href="#JNL">JNL</a>  <br>
  98 <a href="#JNLE">JNLE</a>  <br>
  99
 100 <a href="#JNO">JNO</a>  <br>
 101 <a href="#JNP">JNP</a>  <br>
 102 <a href="#JNS">JNS</a>  <br>
 103 <a href="#JNZ">JNZ</a>  <br>
 104 <a href="#JO">JO</a>  <br>
 105 <a href="#JP">JP</a>  <br>
 106 <a href="#JPE">JPE</a>  <br>
 107 </td><td>
 108 <a href="#JPO">JPO</a>  <br>
 109 <a href="#JS">JS</a>  <br>
 110 <a href="#JZ">JZ</a>  <br>
 111 <a href="#LAHF">LAHF</a>  <br>
 112 <a href="#LDS">LDS</a>  <br>
 113 <a href="#LEA">LEA</a>  <br>
 114 <a href="#LES">LES</a>  <br>
 115
 116 <a href="#LODSB">LODSB</a>  <br>
 117 <a href="#LODSW">LODSW</a>  <br>
 118 <a href="#LOOP">LOOP</a>  <br>
 119 <a href="#LOOPE">LOOPE</a>  <br>
 120 <a href="#LOOPNE">LOOPNE</a>  <br>
 121 <a href="#LOOPNZ">LOOPNZ</a>  <br>
 122 <a href="#LOOPZ">LOOPZ</a>  <br>
 123 </td><td>
 124 <a href="#MOV">MOV</a>  <br>
 125 <a href="#MOVSB">MOVSB</a>  <br>
 126 <a href="#MOVSW">MOVSW</a>  <br>
 127 <a href="#MUL">MUL</a>  <br>
 128 <a href="#NEG">NEG</a>  <br>
 129 <a href="#NOP">NOP</a>  <br>
 130
 131 <a href="#NOT">NOT</a>  <br>
 132
 133 <a href="#OR">OR</a>  <br>
 134
 135 <a href="#OUT">OUT</a>  <br>
 136
 137 <a href="#POP">POP</a>  <br>
 138 <a href="#POPA">POPA</a>  <br>
 139 <a href="#POPF">POPF</a>  <br>
 140 <a href="#PUSH">PUSH</a>  <br>
 141 <a href="#PUSHA">PUSHA</a>  <br>
 142 <a href="#PUSHF">PUSHF</a>  <br>
 143 <a href="#RCL">RCL</a>  <br>
 144 </td><td>
 145 <a href="#RCR">RCR</a>  <br>
 146 <a href="#REP">REP</a>  <br>
 147 <a href="#REPE">REPE</a>  <br>
 148 <a href="#REPNE">REPNE</a>  <br>
 149 <a href="#REPNZ">REPNZ</a>  <br>
 150 <a href="#REPZ">REPZ</a>  <br>
 151 <a href="#RET">RET</a>  <br>
 152
 153 <a href="#RETF">RETF</a>  <br>
 154 <a href="#ROL">ROL</a>  <br>
 155 <a href="#ROR">ROR</a>  <br>
 156 <a href="#SAHF">SAHF</a>  <br>
 157 <a href="#SAL">SAL</a>  <br>
 158 <a href="#SAR">SAR</a>  <br>
 159 <a href="#SBB">SBB</a>  <br>
 160 </td><td>
 161 <a href="#SCASB">SCASB</a>  <br>
 162 <a href="#SCASW">SCASW</a>  <br>
 163 <a href="#SHL">SHL</a>  <br>
 164 <a href="#SHR">SHR</a>  <br>
 165 <a href="#STC">STC</a>  <br>
 166 <a href="#STD">STD</a>  <br>
 167 <a href="#STI">STI</a>  <br>
 168
 169 <a href="#STOSB">STOSB</a>  <br>
 170 <a href="#STOSW">STOSW</a>  <br>
 171 <a href="#SUB">SUB</a>  <br>
 172 <a href="#TEST">TEST</a>  <br>
 173 <a href="#XCHG">XCHG</a>  <br>
 174 <a href="#XLATB">XLATB</a>  <br>
 175 <a href="#XOR">XOR</a>  <br>
 176 </td>
 177 </tr>
 178 </tbody></table>
 179
 180 </font>
 181 <br><br>
 182
 183 </font><hr>
 184
 185
 186 <font size="3" face="Verdana">Operand types:<br><br>
 187
 188 <b>REG</b>: AX, BX, CX, DX, AH, AL, BL, BH, CH, CL, DH, DL, DI, SI, BP, SP.<br><br>
 189
 190 <b>SREG</b>: DS, ES, SS, and only as second operand: CS.<br><br>
 191
 192 <b>memory</b>: [BX], [BX+SI+7], variable, etc...(see <a href="http://www.emu8086.com/assembly_language_tutorial_assembler_reference/asm_tutorial_02.html"><b>Memory Access</b></a>).<br><br>
 193
 194 <b>immediate</b>: 5, -24, 3Fh, 10001101b, etc...<br><br>
 195
 196 </font><hr>
 197
 198 <font size="3" face="Verdana"><br>
 199 Notes:<br><br>
 200 </font><ul>
 201 <font size="3" face="Verdana"><li>When two operands are required for an instruction they are separated by comma. For example:<br><br>
 202         <font face="Fixedsys">
 203         REG, memory
 204         </font>
 205         <br><br></li>
 206 <li>When there are two operands, both operands must have the same size (except shift and rotate
 207     instructions). For example:<br><br>
 208     <font face="Fixedsys">
 209         AL, DL<br>
 210         DX, AX<br>
 211         <font color="#005555">
 212         m1 DB ?<br>
 213         </font>
 214         AL, m1<br>
 215         <font color="#005555">
 216         m2 DW ?<br>
 217         </font>
 218         AX, m2
 219         </font>
 220         <br><br>
 221     </li>
 222         <li>Some instructions allow several operand combinations.
 223          For example:<br><br>
 224         <font face="Fixedsys">
 225                 memory, immediate<br>
 226                 REG, immediate<br><br>
 227                 memory, REG<br>
 228                 REG, SREG
 229         </font><br><br>
 230         </li>
 231
 232  <li>Some examples contain macros, so it is advisable to use <nobr><b>Shift + F8</b></nobr>
 233  hot key to <i>Step Over</i> (to make macro code execute at maximum speed set <b>step delay</b>
 234  to zero), otherwise emulator will step through each instruction of a macro.
 235  Here is an example that uses PRINTN macro:
 236  <pre> <font face="Fixedsys">
 237
 238    include 'emu8086.inc'
 239    ORG 100h
 240    MOV AL, 1
 241    MOV BL, 2
 242    PRINTN 'Hello World!'   ; macro.
 243    MOV CL, 3
 244    PRINTN 'Welcome!'       ; macro.
 245    RET</font></pre>
 246  </li>
 247
 248 </font></ul>
 249 <font size="3" face="Verdana"><br>
 250
 251 </font><hr>
 252 <font size="3" face="Verdana"><br><br>
 253 These marks are used to show the state of the flags:<br><br>
 254 <b>1</b> - instruction sets this flag to <b>1</b>.<br>
 255 <b>0</b> - instruction sets this flag to <b>0</b>.<br>
 256 <b>r</b> - flag value depends on result of the instruction.<br>
 257 <b>?</b> - flag value is undefined (maybe <b>1</b> or <b>0</b>).<br>
 258 <br><br>
 259
 260 </font><hr>
 261
 262 <font size="3" face="Verdana"><br><br><b>
 263 Some instructions generate exactly the same machine code, so disassembler
 264 may have a problem decoding to your original code. This is especially
 265 important for Conditional Jump instructions (see
 266 "<a href="http://www.emu8086.com/assembly_language_tutorial_assembler_reference/asm_tutorial_07.html">Program Flow Control</a>"
 267 in Tutorials for more information).</b>
 268 <br><br><br>
 269 </font><hr>
 270
 271 <font size="3" face="Verdana"><br><br>
 272 Instructions in alphabetical order:
 273
 274 <br><br>
 275
 276 <table border="1" cellpadding="10" width="100%">
 277
 278 <tbody><tr>
 279 <td>Instruction</td> <td>Operands</td> <td>Description
 280                         <a name="AAA">&nbsp;</a>
 281 </td>
 282 </tr>
 283
 284
 285
 286
 287 <tr>
 288 <td>
 289 <font face="Fixedsys">
 290 AAA
 291 </font>
 292 </td>
 293 <td>No operands</td>
 294 <td>
 295
 296 ASCII Adjust after Addition.<br>
 297 Corrects result in AH and AL after addition
 298 when working with BCD values. <br><br> It works according to the following Algorithm:
 299 <br><br>
 300 <font face="Fixedsys">
 301 if low nibble of AL &gt; 9 or AF = 1 then:<br>
 302 <ul>
 303 <li>AL = AL + 6</li>
 304 <li>AH = AH + 1</li>
 305 <li>AF = 1</li>
 306 <li>CF = 1</li>
 307 </ul>
 308 else
 309 <ul>
 310 <li>AF = 0</li>
 311 <li>CF = 0</li>
 312 </ul>
 313 in both cases:<br>
 314 clear the high nibble of AL.
 315 </font>
 316 <br><br>Example:<pre><font face="Fixedsys">MOV AX, 15   ; AH = 00, AL = 0Fh
 317 AAA          ; AH = 01, AL = 05
 318 RET</font></pre>
 319
 320 <font face="Fixedsys">
 321 <table noshade="" border="1">
 322 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
 323 <tr> <td>r</td> <td>?</td> <td>?</td> <td>?</td> <td>?</td> <td>r</td> </tr>
 324 </tbody></table>
 325 </font>
 326
 327 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
 328
 329
 330                         <a name="AAD">&nbsp;</a>
 331 </td>
 332 </tr>
 333
 334
 335
 336
 337 <tr>
 338 <td>
 339 <font face="Fixedsys">
 340 AAD
 341 </font>
 342 </td>
 343 <td>No operands</td>
 344 <td>
 345
 346 ASCII Adjust before Division.<br>
 347 Prepares two BCD values for division. <br><br>Algorithm:
 348 <br><br>
 349 <font face="Fixedsys">
 350 <ul>
 351 <li>AL = (AH * 10) + AL</li>
 352 <li>AH = 0</li>
 353 </ul>
 354 </font>
 355 <br>Example:<pre><font face="Fixedsys">MOV AX, 0105h   ; AH = 01, AL = 05
 356 AAD             ; AH = 00, AL = 0Fh (15)
 357 RET</font></pre>
 358
 359 <font face="Fixedsys">
 360 <table noshade="" border="1">
 361 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
 362 <tr> <td>?</td> <td>r</td> <td>r</td> <td>?</td> <td>r</td> <td>?</td> </tr>
 363 </tbody></table>
 364 </font>
 365
 366 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
 367
 368
 369                         <a name="AAM">&nbsp;</a>
 370 </td>
 371 </tr>
 372
 373
 374
 375
 376 <tr>
 377 <td>
 378 <font face="Fixedsys">
 379 AAM
 380 </font>
 381 </td>
 382 <td>No operands</td>
 383 <td>
 384
 385 ASCII Adjust after Multiplication.<br>
 386 Corrects the result of multiplication of two BCD values. <br><br>Algorithm:
 387 <br><br>
 388 <font face="Fixedsys">
 389 <ul>
 390 <li>AH = AL / 10</li>
 391 <li>AL = remainder</li>
 392 </ul>
 393 </font>
 394 <br>Example:<pre><font face="Fixedsys">MOV AL, 15   ; AL = 0Fh
 395 AAM          ; AH = 01, AL = 05
 396 RET</font></pre>
 397
 398 <font face="Fixedsys">
 399 <table noshade="" border="1">
 400 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
 401 <tr> <td>?</td> <td>r</td> <td>r</td> <td>?</td> <td>r</td> <td>?</td> </tr>
 402 </tbody></table>
 403 </font>
 404
 405 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
 406
 407
 408                         <a name="AAS">&nbsp;</a>
 409 </td>
 410 </tr>
 411
 412
 413
 414
 415 <tr>
 416 <td>
 417 <font face="Fixedsys">
 418 AAS
 419 </font>
 420 </td>
 421 <td>No operands</td>
 422 <td>
 423
 424 ASCII Adjust after Subtraction.<br>
 425 Corrects result in AH and AL after subtraction
 426 when working with BCD values. <br><br>Algorithm:<br><br>
 427 <font face="Fixedsys">
 428 if low nibble of AL &gt; 9 or AF = 1 then:<br>
 429 <ul>
 430 <li>AL = AL - 6</li>
 431 <li>AH = AH - 1</li>
 432 <li>AF = 1</li>
 433 <li>CF = 1</li>
 434 </ul>
 435 else
 436 <ul>
 437 <li>AF = 0</li>
 438 <li>CF = 0</li>
 439 </ul>
 440 in both cases:<br>
 441 clear the high nibble of AL.
 442 </font>
 443 <br><br>Example:<pre><font face="Fixedsys">MOV AX, 02FFh  ; AH = 02, AL = 0FFh
 444 AAS            ; AH = 01, AL = 09
 445 RET</font></pre>
 446
 447 <font face="Fixedsys">
 448 <table noshade="" border="1">
 449 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
 450 <tr> <td>r</td> <td>?</td> <td>?</td> <td>?</td> <td>?</td> <td>r</td> </tr>
 451 </tbody></table>
 452 </font>
 453
 454 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
 455
 456
 457                         <a name="ADC">&nbsp;</a>
 458 </td>
 459 </tr>
 460
 461
 462
 463
 464 <tr>
 465 <td>
 466 <font face="Fixedsys">
 467 ADC
 468 </font>
 469 </td>
 470 <td>
 471 <font face="Fixedsys">
 472         <nobr>
 473         REG, memory<br>
 474         memory, REG<br>
 475         REG, REG<br>
 476         memory, immediate<br>
 477         REG, immediate
 478         </nobr>
 479 </font>
 480 </td>
 481 <td>
 482
 483 Add with Carry.<br>
 484 <br><br>Algorithm:<br><br>
 485 <font face="Fixedsys">
 486 operand1 = operand1 + operand2 + CF
 487 </font>
 488 <br><br>Example:<pre><font face="Fixedsys">STC        ; set CF = 1
 489 MOV AL, 5  ; AL = 5
 490 ADC AL, 1  ; AL = 7
 491 RET</font></pre>
 492
 493 <font face="Fixedsys">
 494 <table noshade="" border="1">
 495 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
 496 <tr> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> </tr>
 497 </tbody></table>
 498 </font>
 499
 500 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
 501
 502
 503                         <a name="ADD">&nbsp;</a>
 504 </td>
 505 </tr>
 506
 507
 508
 509
 510 <tr>
 511 <td>
 512 <font face="Fixedsys">
 513 ADD
 514 </font>
 515 </td>
 516 <td>
 517 <font face="Fixedsys">
 518         <nobr>
 519         REG, memory<br>
 520         memory, REG<br>
 521         REG, REG<br>
 522         memory, immediate<br>
 523         REG, immediate
 524         </nobr>
 525 </font>
 526 </td>
 527 <td>
 528
 529 Add.<br>
 530 <br><br>Algorithm:<br><br>
 531 <font face="Fixedsys">
 532 operand1 = operand1 + operand2
 533 </font>
 534 <br><br>Example:<pre><font face="Fixedsys">MOV AL, 5   ; AL = 5
 535 ADD AL, -3  ; AL = 2
 536 RET</font></pre>
 537
 538 <font face="Fixedsys">
 539 <table noshade="" border="1">
 540 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
 541 <tr> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> </tr>
 542 </tbody></table>
 543 </font>
 544
 545 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
 546
 547
 548                         <a name="AND">&nbsp;</a>
 549 </td>
 550 </tr>
 551
 552
 553
 554
 555 <tr>
 556 <td>
 557 <font face="Fixedsys">
 558 AND
 559 </font>
 560 </td>
 561 <td>
 562 <font face="Fixedsys">
 563         <nobr>
 564         REG, memory<br>
 565         memory, REG<br>
 566         REG, REG<br>
 567         memory, immediate<br>
 568         REG, immediate
 569         </nobr>
 570 </font>
 571 </td>
 572 <td>
 573
 574 Logical AND between all bits of two operands. Result is stored in operand1.<br><br>
 575 These rules apply:<br><br>
 576 <font face="Fixedsys">
 577 1 AND 1 = 1<br>
 578 1 AND 0 = 0<br>
 579 0 AND 1 = 0<br>
 580 0 AND 0 = 0<br>
 581 </font>
 582 <br><br>Example:<pre><font face="Fixedsys">MOV AL, 'a'        ; AL = 01100001b
 583 AND AL, 11011111b  ; AL = 01000001b  ('A')
 584 RET</font></pre>
 585
 586 <font face="Fixedsys">
 587 <table noshade="" border="1">
 588 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> </tr>
 589 <tr> <td>0</td> <td>r</td> <td>r</td> <td>0</td> <td>r</td> </tr>
 590 </tbody></table>
 591 </font>
 592
 593 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
 594
 595
 596                         <a name="CALL">&nbsp;</a>
 597 </td>
 598 </tr>
 599
 600
 601
 602
 603 <tr>
 604 <td>
 605 <font face="Fixedsys">
 606 CALL
 607 </font>
 608 </td>
 609 <td>
 610 <font face="Fixedsys">
 611         <nobr>
 612         procedure name<br>
 613         label<br>
 614         4-byte address<br>
 615         </nobr>
 616 </font>
 617 </td>
 618 <td>
 619
 620 Transfers control to procedure, return address is (IP) is pushed to
 621 stack. <i>4-byte address</i> may be entered in this form:
 622 <font face="Fixedsys">1234h:5678h</font>, first value is a segment second
 623 value is an offset (this is a far call, so CS is also pushed to stack).<br>
 624 <br><br>Example:<pre><font face="Fixedsys">
 625 ORG 100h  ; directive to make simple .com file.
 626
 627 CALL p1
 628
 629 ADD AX, 1
 630
 631 RET         ; return to OS.
 632
 633 p1 PROC     ; procedure declaration.
 634     MOV AX, 1234h
 635     RET     ; return to caller.
 636 p1 ENDP</font></pre>
 637
 638 <font face="Fixedsys">
 639 <table noshade="" border="1">
 640 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
 641 <tr> <td colspan="6">unchanged</td> </tr>
 642 </tbody></table>
 643 </font>
 644
 645 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
 646
 647
 648                         <a name="CBW">&nbsp;</a>
 649 </td>
 650 </tr>
 651
 652
 653
 654
 655 <tr>
 656 <td>
 657 <font face="Fixedsys">
 658 CBW
 659 </font>
 660 </td>
 661 <td>No operands</td>
 662 <td>
 663
 664 Convert byte into word. <br><br>Algorithm:
 665 <br><br>
 666 <font face="Fixedsys">
 667 if high bit of AL = 1 then:
 668 <ul>
 669 <li>AH = 255 (0FFh)</li>
 670 </ul>
 671 <br>
 672 else
 673 <ul>
 674 <li>AH = 0</li>
 675 </ul>
 676 </font>
 677 <br>Example:<pre><font face="Fixedsys">MOV AX, 0   ; AH = 0, AL = 0
 678 MOV AL, -5  ; AX = 000FBh (251)
 679 CBW         ; AX = 0FFFBh (-5)
 680 RET</font></pre>
 681
 682 <font face="Fixedsys">
 683 <table noshade="" border="1">
 684 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
 685 <tr> <td colspan="6">unchanged</td> </tr>
 686 </tbody></table>
 687 </font>
 688
 689 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
 690
 691
 692                         <a name="CLC">&nbsp;</a>
 693 </td>
 694 </tr>
 695
 696
 697
 698
 699 <tr>
 700 <td>
 701 <font face="Fixedsys">
 702 CLC
 703 </font>
 704 </td>
 705 <td>No operands</td>
 706 <td>
 707
 708 Clear Carry flag. <br><br>Algorithm:
 709 <br><br>
 710 <font face="Fixedsys">
 711 CF = 0
 712 </font>
 713
 714 <br><br>
 715
 716 <font face="Fixedsys">
 717 <table noshade="" border="1">
 718 <tbody><tr> <td>C</td> </tr>
 719 <tr> <td>0</td> </tr>
 720 </tbody></table>
 721 </font>
 722
 723 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
 724
 725
 726                         <a name="CLD">&nbsp;</a>
 727 </td>
 728 </tr>
 729
 730
 731
 732
 733 <tr>
 734 <td>
 735 <font face="Fixedsys">
 736 CLD
 737 </font>
 738 </td>
 739 <td>No operands</td>
 740 <td>
 741
 742 Clear Direction flag. SI and DI will be incremented by chain
 743 instructions: CMPSB, CMPSW, LODSB, LODSW, MOVSB, MOVSW, STOSB, STOSW. <br><br>Algorithm:
 744 <br><br>
 745 <font face="Fixedsys">
 746 DF = 0
 747 </font>
 748
 749 <br><br>
 750
 751 <font face="Fixedsys">
 752 <table noshade="" border="1">
 753 <tbody><tr> <td>D</td> </tr>
 754 <tr> <td>0</td> </tr>
 755 </tbody></table>
 756 </font>
 757
 758 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
 759
 760
 761                         <a name="CLI">&nbsp;</a>
 762 </td>
 763 </tr>
 764
 765
 766
 767
 768 <tr>
 769 <td>
 770 <font face="Fixedsys">
 771 CLI
 772 </font>
 773 </td>
 774 <td>No operands</td>
 775 <td>
 776
 777 Clear Interrupt enable flag. This disables hardware interrupts. <br><br>Algorithm:
 778 <br><br>
 779 <font face="Fixedsys">
 780 IF = 0
 781 </font>
 782
 783 <br><br>
 784
 785 <font face="Fixedsys">
 786 <table noshade="" border="1">
 787 <tbody><tr> <td>I</td> </tr>
 788 <tr> <td>0</td> </tr>
 789 </tbody></table>
 790 </font>
 791
 792 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
 793
 794
 795                         <a name="CMC">&nbsp;</a>
 796 </td>
 797 </tr>
 798
 799
 800
 801
 802 <tr>
 803 <td>
 804 <font face="Fixedsys">
 805 CMC
 806 </font>
 807 </td>
 808 <td>No operands</td>
 809 <td>
 810
 811 Complement Carry flag. Inverts value of CF. <br><br>Algorithm:
 812 <br><br>
 813 <font face="Fixedsys">
 814 if CF = 1 then CF = 0<br>
 815 if CF = 0 then CF = 1<br>
 816 </font>
 817
 818 <br><br>
 819
 820 <font face="Fixedsys">
 821 <table noshade="" border="1">
 822 <tbody><tr> <td>C</td> </tr>
 823 <tr> <td>r</td> </tr>
 824 </tbody></table>
 825 </font>
 826
 827 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
 828
 829
 830                         <a name="CMP">&nbsp;</a>
 831 </td>
 832 </tr>
 833
 834
 835
 836
 837 <tr>
 838 <td>
 839 <font face="Fixedsys">
 840 CMP
 841 </font>
 842 </td>
 843 <td>
 844 <font face="Fixedsys">
 845         <nobr>
 846         REG, memory<br>
 847         memory, REG<br>
 848         REG, REG<br>
 849         memory, immediate<br>
 850         REG, immediate
 851         </nobr>
 852 </font>
 853 </td>
 854 <td>
 855
 856 Compare.
 857 <br><br>Algorithm:<br><br>
 858 <font face="Fixedsys">
 859 operand1 - operand2
 860 <br><br>
 861 result is not stored anywhere, flags are set (OF, SF, ZF, AF, PF, CF) according
 862 to result.
 863 </font>
 864 <br><br>Example:<pre><font face="Fixedsys">MOV AL, 5
 865 MOV BL, 5
 866 CMP AL, BL  ; AL = 5, ZF = 1 (so equal!)
 867 RET</font></pre>
 868
 869 <font face="Fixedsys">
 870 <table noshade="" border="1">
 871 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
 872 <tr> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> </tr>
 873 </tbody></table>
 874 </font>
 875
 876 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
 877
 878
 879                         <a name="CMPSB">&nbsp;</a>
 880 </td>
 881 </tr>
 882
 883
 884
 885
 886 <tr>
 887 <td>
 888 <font face="Fixedsys">
 889 CMPSB
 890 </font>
 891 </td>
 892 <td>No operands</td>
 893 <td>
 894
 895 Compare bytes: <nobr>ES:[DI] from DS:[SI].</nobr> <br><br>Algorithm:
 896 <br><br>
 897 <font face="Fixedsys">
 898 </font><ul>
 899 <font face="Fixedsys"><li>DS:[SI] - ES:[DI]<br></li>
 900 <li>set flags according to result:<br> OF, SF, ZF, AF, PF, CF<br></li>
 901 <li>if DF = 0 then
 902         <ul>
 903         <li>SI = SI + 1</li>
 904         <li>DI = DI + 1</li>
 905         </ul>
 906         else
 907         <ul>
 908         <li>SI = SI - 1</li>
 909         <li>DI = DI - 1</li>
 910         </ul>
 911 </li>
 912 </font></ul>
 913 <font face="Fixedsys"></font>
 914 Example:<br>
 915 see <b><a href="http://www.emu8086.com/dr/asm2html/assembler_source_code/cmpsb.asm.html" target="_blank">cmpsb.asm</a></b> in c:\emu8086\examples\.
 916
 917 <br><br>
 918
 919 <font face="Fixedsys">
 920 <table noshade="" border="1">
 921 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
 922 <tr> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> </tr>
 923 </tbody></table>
 924 </font>
 925
 926 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
 927
 928
 929                         <a name="CMPSW">&nbsp;</a>
 930 </td>
 931 </tr>
 932
 933
 934
 935
 936 <tr>
 937 <td>
 938 <font face="Fixedsys">
 939 CMPSW
 940 </font>
 941 </td>
 942 <td>No operands</td>
 943 <td>
 944
 945 Compare words: <nobr>ES:[DI] from DS:[SI].</nobr> <br><br>Algorithm:
 946 <br><br>
 947 <font face="Fixedsys">
 948 <ul>
 949 <li>DS:[SI] - ES:[DI]<br></li>
 950 <li>set flags according to result:<br> OF, SF, ZF, AF, PF, CF<br></li>
 951 <li>if DF = 0 then
 952         <ul>
 953         <li>SI = SI + 2</li>
 954         <li>DI = DI + 2</li>
 955         </ul>
 956         else
 957         <ul>
 958         <li>SI = SI - 2</li>
 959         <li>DI = DI - 2</li>
 960         </ul>
 961 </li>
 962 </ul>
 963 </font>
 964 Example:<br>
 965 see <b><a href="http://www.emu8086.com/dr/asm2html/assembler_source_code/cmpsw.asm.html" target="_blank">cmpsw.asm</a></b> in c:\emu8086\examples\.
 966
 967 <br><br>
 968
 969 <font face="Fixedsys">
 970 <table noshade="" border="1">
 971 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
 972 <tr> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> </tr>
 973 </tbody></table>
 974 </font>
 975
 976 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
 977
 978
 979                         <a name="CWD">&nbsp;</a>
 980 </td>
 981 </tr>
 982
 983
 984
 985
 986 <tr>
 987 <td>
 988 <font face="Fixedsys">
 989 CWD
 990 </font>
 991 </td>
 992 <td>No operands</td>
 993 <td>
 994
 995 Convert Word to Double word. <br><br>Algorithm:
 996 <br><br>
 997 <font face="Fixedsys">
 998 if high bit of AX = 1 then:
 999 <ul>
1000 <li>DX = 65535 (0FFFFh)</li>
1001 </ul>
1002 <br>
1003 else
1004 <ul>
1005 <li>DX = 0</li>
1006 </ul>
1007 </font>
1008 <br>Example:<pre><font face="Fixedsys">MOV DX, 0   ; DX = 0
1009 MOV AX, 0   ; AX = 0
1010 MOV AX, -5  ; DX AX = 00000h:0FFFBh
1011 CWD         ; DX AX = 0FFFFh:0FFFBh
1012 RET</font></pre>
1013
1014 <font face="Fixedsys">
1015 <table noshade="" border="1">
1016 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
1017 <tr> <td colspan="6">unchanged</td> </tr>
1018 </tbody></table>
1019 </font>
1020
1021 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1022
1023
1024                         <a name="DAA">&nbsp;</a>
1025 </td>
1026 </tr>
1027
1028
1029
1030
1031 <tr>
1032 <td>
1033 <font face="Fixedsys">
1034 DAA
1035 </font>
1036 </td>
1037 <td>No operands</td>
1038 <td>
1039
1040 Decimal adjust After Addition.<br>
1041 Corrects the result of addition of two packed BCD values. <br><br>Algorithm:
1042 <br><br>
1043 <font face="Fixedsys">
1044 if low nibble of AL &gt; 9 or AF = 1 then:<br>
1045 </font><ul>
1046 <font face="Fixedsys"><li>AL = AL + 6</li>
1047 <li>AF = 1</li>
1048 </font></ul>
1049 <font face="Fixedsys">if AL &gt; 9Fh or CF = 1 then:
1050 </font><ul>
1051 <font face="Fixedsys"><li>AL = AL + 60h</li>
1052 <li>CF = 1</li>
1053 </font></ul>
1054 <font face="Fixedsys"></font>
1055 <br>Example:<pre><font face="Fixedsys">MOV AL, 0Fh  ; AL = 0Fh (15)
1056 DAA          ; AL = 15h
1057 RET</font></pre>
1058
1059 <font face="Fixedsys">
1060 <table noshade="" border="1">
1061 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
1062 <tr> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> </tr>
1063 </tbody></table>
1064 </font>
1065
1066 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1067
1068
1069                         <a name="DAS">&nbsp;</a>
1070 </td>
1071 </tr>
1072
1073
1074
1075
1076 <tr>
1077 <td>
1078 <font face="Fixedsys">
1079 DAS
1080 </font>
1081 </td>
1082 <td>No operands</td>
1083 <td>
1084
1085 Decimal adjust After Subtraction.<br>
1086 Corrects the result of subtraction of two packed BCD values. <br><br>Algorithm:
1087 <br><br>
1088 <font face="Fixedsys">
1089 if low nibble of AL &gt; 9 or AF = 1 then:<br>
1090 <ul>
1091 <li>AL = AL - 6</li>
1092 <li>AF = 1</li>
1093 </ul>
1094 if AL &gt; 9Fh or CF = 1 then:
1095 <ul>
1096 <li>AL = AL - 60h</li>
1097 <li>CF = 1</li>
1098 </ul>
1099 </font>
1100 <br>Example:<pre><font face="Fixedsys">MOV AL, 0FFh  ; AL = 0FFh (-1)
1101 DAS           ; AL = 99h, CF = 1
1102 RET</font></pre>
1103
1104 <font face="Fixedsys">
1105 <table noshade="" border="1">
1106 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
1107 <tr> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> </tr>
1108 </tbody></table>
1109 </font>
1110
1111 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1112
1113
1114                         <a name="DEC">&nbsp;</a>
1115 </td>
1116 </tr>
1117
1118
1119
1120
1121 <tr>
1122 <td>
1123 <font face="Fixedsys">
1124 DEC
1125 </font>
1126 </td>
1127 <td>
1128 <font face="Fixedsys">
1129         <nobr>
1130         REG<br>
1131         memory<br>
1132         </nobr>
1133 </font>
1134 </td>
1135 <td>
1136
1137 Decrement.
1138 <br><br>Algorithm:<br><br>
1139 <font face="Fixedsys">
1140 operand = operand - 1
1141 <br><br>
1142 </font>
1143 <br>Example:<pre><font face="Fixedsys">MOV AL, 255  ; AL = 0FFh (255 or -1)
1144 DEC AL       ; AL = 0FEh (254 or -2)
1145 RET</font></pre>
1146
1147 <font face="Fixedsys">
1148 <table noshade="" border="1">
1149 <tbody><tr> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
1150 <tr> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> </tr>
1151 </tbody></table>
1152 CF - unchanged!
1153 </font>
1154
1155 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1156
1157
1158                         <a name="DIV">&nbsp;</a>
1159 </td>
1160 </tr>
1161
1162
1163
1164
1165 <tr>
1166 <td>
1167 <font face="Fixedsys">
1168 DIV
1169 </font>
1170 </td>
1171 <td>
1172 <font face="Fixedsys">
1173         <nobr>
1174         REG<br>
1175         memory<br>
1176         </nobr>
1177 </font>
1178 </td>
1179 <td>
1180
1181 Unsigned divide.
1182 <br><br>Algorithm:<br><br>
1183  <blockquote>
1184          when operand is a <b>byte</b>:<br>
1185          <font face="Fixedsys">AL = AX / operand<br>
1186          AH = remainder (modulus)
1187          </font>
1188  </blockquote>
1189
1190  <blockquote>
1191         when operand is a <b>word</b>:<br>
1192         <font face="Fixedsys">AX = (DX AX) / operand<br>
1193         DX = remainder (modulus)
1194         </font>
1195  </blockquote>
1196  Example:<pre><font face="Fixedsys">MOV AX, 203   ; AX = 00CBh
1197 MOV BL, 4
1198 DIV BL        ; AL = 50 (32h), AH = 3
1199 RET</font></pre>
1200
1201 <font face="Fixedsys">
1202 <table noshade="" border="1">
1203 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
1204 <tr> <td>?</td> <td>?</td> <td>?</td> <td>?</td> <td>?</td> <td>?</td> </tr>
1205 </tbody></table>
1206 </font>
1207
1208 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1209
1210
1211                         <a name="HLT">&nbsp;</a>
1212 </td>
1213 </tr>
1214
1215
1216
1217
1218
1219
1220 <tr>
1221 <td>
1222 <font face="Fixedsys">
1223 HLT
1224 </font>
1225 </td>
1226 <td>No operands</td>
1227 <td>
1228
1229 Halt the System.<br><br>
1230
1231  Example:<pre><font face="Fixedsys">MOV AX, 5
1232 HLT</font></pre>
1233
1234 <font face="Fixedsys">
1235 <table noshade="" border="1">
1236 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
1237 <tr> <td colspan="6">unchanged</td> </tr>
1238 </tbody></table>
1239 </font>
1240
1241 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1242
1243
1244                         <a name="IDIV">&nbsp;</a>
1245 </td>
1246 </tr>
1247
1248
1249
1250
1251
1252 <tr>
1253 <td>
1254 <font face="Fixedsys">
1255 IDIV
1256 </font>
1257 </td>
1258 <td>
1259 <font face="Fixedsys">
1260         <nobr>
1261         REG<br>
1262         memory<br>
1263         </nobr>
1264 </font>
1265 </td>
1266 <td>
1267
1268 Signed divide.
1269 <br><br>Algorithm:<br><br>
1270  <blockquote>
1271          when operand is a <b>byte</b>:<br>
1272          <font face="Fixedsys">AL = AX / operand<br>
1273          AH = remainder (modulus)
1274          </font>
1275  </blockquote>
1276
1277  <blockquote>
1278         when operand is a <b>word</b>:<br>
1279         <font face="Fixedsys">AX = (DX AX) / operand<br>
1280         DX = remainder (modulus)
1281         </font>
1282  </blockquote>
1283  Example:<pre><font face="Fixedsys">MOV AX, -203 ; AX = 0FF35h
1284 MOV BL, 4
1285 IDIV BL      ; AL = -50 (0CEh), AH = -3 (0FDh)
1286 RET</font></pre>
1287
1288 <font face="Fixedsys">
1289 <table noshade="" border="1">
1290 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
1291 <tr> <td>?</td> <td>?</td> <td>?</td> <td>?</td> <td>?</td> <td>?</td> </tr>
1292 </tbody></table>
1293 </font>
1294
1295 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1296
1297
1298                         <a name="IMUL">&nbsp;</a>
1299 </td>
1300 </tr>
1301
1302
1303
1304
1305 <tr>
1306 <td>
1307 <font face="Fixedsys">
1308 IMUL
1309 </font>
1310 </td>
1311 <td>
1312 <font face="Fixedsys">
1313         <nobr>
1314         REG<br>
1315         memory<br>
1316         </nobr>
1317 </font>
1318 </td>
1319 <td>
1320
1321 Signed multiply.
1322 <br><br>Algorithm:<br><br>
1323  <blockquote>
1324          when operand is a <b>byte</b>:<br>
1325          <font face="Fixedsys">AX = AL * operand</font>.
1326  </blockquote>
1327
1328  <blockquote>
1329         when operand is a <b>word</b>:<br>
1330         <font face="Fixedsys">(DX AX) = AX * operand</font>.
1331  </blockquote>
1332   Example:<pre><font face="Fixedsys">MOV AL, -2
1333 MOV BL, -4
1334 IMUL BL      ; AX = 8
1335 RET</font></pre>
1336
1337 <font face="Fixedsys">
1338 <table noshade="" border="1">
1339 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
1340 <tr> <td>r</td> <td>?</td> <td>?</td> <td>r</td> <td>?</td> <td>?</td> </tr>
1341 </tbody></table>
1342 CF=OF=0 when result fits into operand of IMUL.
1343 </font>
1344
1345 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1346
1347
1348                         <a name="IN">&nbsp;</a>
1349 </td>
1350 </tr>
1351
1352
1353 <tr>
1354 <td>
1355 <font face="Fixedsys">
1356 IN
1357 </font>
1358 </td>
1359 <td>
1360 <font face="Fixedsys">
1361         <nobr>
1362         AL, im.byte<br>
1363         AL, DX<br>
1364         AX, im.byte<br>
1365         AX, DX
1366         </nobr>
1367 </font>
1368 </td>
1369 <td>
1370
1371 Input from port into <b>AL</b> or <b>AX</b>.<br>
1372 Second operand is a port number. If required to access
1373 port number over 255 - <b>DX</b> register should be used.
1374 <br>Example:<pre><font face="Fixedsys">IN AX, 4  ; get status of traffic lights.
1375 IN AL, 7  ; get status of stepper-motor.
1376 </font></pre>
1377
1378 <font face="Fixedsys">
1379 <table noshade="" border="1">
1380 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
1381 <tr> <td colspan="6">unchanged</td> </tr>
1382 </tbody></table>
1383 </font>
1384
1385 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1386
1387
1388                         <a name="INC">&nbsp;</a>
1389 </td>
1390 </tr>
1391
1392
1393 <tr>
1394 <td>
1395 <font face="Fixedsys">
1396 INC
1397 </font>
1398 </td>
1399 <td>
1400 <font face="Fixedsys">
1401         <nobr>
1402         REG<br>
1403         memory<br>
1404         </nobr>
1405 </font>
1406 </td>
1407 <td>
1408
1409 Increment.
1410 <br><br>Algorithm:<br><br>
1411 <font face="Fixedsys">
1412 operand = operand + 1
1413 <br>
1414 </font>
1415 <br>Example:<pre><font face="Fixedsys">MOV AL, 4
1416 INC AL       ; AL = 5
1417 RET</font></pre>
1418
1419 <font face="Fixedsys">
1420 <table noshade="" border="1">
1421 <tbody><tr> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
1422 <tr> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> </tr>
1423 </tbody></table>
1424 CF - unchanged!
1425 </font>
1426
1427 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1428
1429
1430                         <a name="INT">&nbsp;</a>
1431 </td>
1432 </tr>
1433
1434
1435
1436
1437 <tr>
1438 <td>
1439 <font face="Fixedsys">
1440 INT
1441 </font>
1442 </td>
1443 <td>
1444 <font face="Fixedsys">
1445         <nobr>immediate byte</nobr>
1446 </font>
1447 </td>
1448 <td>
1449
1450 Interrupt numbered by immediate byte (0..255).
1451 <br><br>Algorithm:<br><br>
1452 <font face="Fixedsys">
1453 <ul>
1454         Push to stack:
1455         <ul>
1456         <li>flags register</li>
1457         <li>CS</li>
1458         <li>IP</li>
1459         </ul>
1460
1461         <li>IF = 0</li>
1462
1463         <li>Transfer control to interrupt procedure</li>
1464 </ul>
1465 </font>
1466 <br>Example:<pre><font face="Fixedsys">MOV AH, 0Eh  ; teletype.
1467 MOV AL, 'A'
1468 INT 10h      ; BIOS interrupt.
1469 RET</font></pre>
1470
1471 <font face="Fixedsys">
1472 <table noshade="" border="1">
1473 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> <td>I</td> </tr>
1474 <tr> <td colspan="6">unchanged</td> <td>0</td></tr>
1475 </tbody></table>
1476 </font>
1477
1478 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1479
1480
1481                         <a name="INTO">&nbsp;</a>
1482 </td>
1483 </tr>
1484
1485
1486
1487 <tr>
1488 <td>
1489 <font face="Fixedsys">
1490 INTO
1491 </font>
1492 </td>
1493 <td>No operands</td>
1494 <td>
1495
1496 Interrupt 4 if Overflow flag is 1.
1497 <br><br>Algorithm:<br><br>
1498 <font face="Fixedsys">
1499 if OF = 1 then INT 4
1500 <br>
1501 </font>
1502 <br>Example:<pre><font face="Fixedsys">; -5 - 127 = -132 (not in -128..127)
1503 ; the result of SUB is wrong (124),
1504 ; so OF = 1 is set:
1505 MOV AL, -5
1506 SUB AL, 127   ; AL = 7Ch (124)
1507 INTO          ; process error.
1508 RET</font></pre>
1509
1510 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1511
1512
1513                         <a name="IRET">&nbsp;</a>
1514 </td>
1515 </tr>
1516
1517
1518
1519
1520 <tr>
1521 <td>
1522 <font face="Fixedsys">
1523 IRET
1524 </font>
1525 </td>
1526 <td>No operands</td>
1527 <td>
1528
1529 Interrupt Return.
1530 <br><br>Algorithm:<br><br>
1531 <font face="Fixedsys">
1532 <ul>
1533         Pop from stack:
1534         <ul>
1535         <li>IP</li>
1536         <li>CS</li>
1537         <li>flags register</li>
1538         </ul>
1539 </ul>
1540 </font>
1541
1542 <font face="Fixedsys">
1543 <table noshade="" border="1">
1544 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
1545 <tr> <td colspan="6"><center>popped</center></td> </tr>
1546 </tbody></table>
1547 </font>
1548
1549 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1550
1551
1552                         <a name="JA">&nbsp;</a>
1553 </td>
1554 </tr>
1555
1556
1557
1558
1559 <tr>
1560 <td>
1561 <font face="Fixedsys">
1562 JA
1563 </font>
1564 </td>
1565 <td>
1566 <font face="Fixedsys">
1567         <nobr>label</nobr>
1568 </font>
1569 </td>
1570 <td>
1571
1572 Short Jump if first operand is Above second operand (as set by CMP instruction).
1573 Unsigned.
1574 <br><br>Algorithm:<br><br>
1575 <font face="Fixedsys">
1576 <ul>
1577         if (CF = 0) and (ZF = 0) then jump
1578 </ul>
1579 </font>
1580 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
1581
1582    ORG 100h
1583    MOV AL, 250
1584    CMP AL, 5
1585    JA label1
1586    PRINT 'AL is not above 5'
1587    JMP exit
1588 label1:
1589    PRINT 'AL is above 5'
1590 exit:
1591    RET</font></pre>
1592
1593 <font face="Fixedsys">
1594 <table noshade="" border="1">
1595 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
1596 <tr> <td colspan="6">unchanged</td> </tr>
1597 </tbody></table>
1598 </font>
1599
1600 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1601
1602
1603                         <a name="JAE">&nbsp;</a>
1604 </td>
1605 </tr>
1606
1607
1608
1609
1610 <tr>
1611 <td>
1612 <font face="Fixedsys">
1613 JAE
1614 </font>
1615 </td>
1616 <td>
1617 <font face="Fixedsys">
1618         <nobr>label</nobr>
1619 </font>
1620 </td>
1621 <td>
1622
1623 Short Jump if first operand is Above or Equal to second operand (as set by CMP instruction).
1624 Unsigned.
1625 <br><br>Algorithm:<br><br>
1626 <font face="Fixedsys">
1627 <ul>
1628         if CF = 0 then jump
1629 </ul>
1630 </font>
1631 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
1632
1633    ORG 100h
1634    MOV AL, 5
1635    CMP AL, 5
1636    JAE label1
1637    PRINT 'AL is not above or equal to 5'
1638    JMP exit
1639 label1:
1640    PRINT 'AL is above or equal to 5'
1641 exit:
1642    RET</font></pre>
1643
1644 <font face="Fixedsys">
1645 <table noshade="" border="1">
1646 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
1647 <tr> <td colspan="6">unchanged</td> </tr>
1648 </tbody></table>
1649 </font>
1650
1651 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1652
1653
1654                         <a name="JB">&nbsp;</a>
1655 </td>
1656 </tr>
1657
1658
1659
1660
1661 <tr>
1662 <td>
1663 <font face="Fixedsys">
1664 JB
1665 </font>
1666 </td>
1667 <td>
1668 <font face="Fixedsys">
1669         <nobr>label</nobr>
1670 </font>
1671 </td>
1672 <td>
1673
1674 Short Jump if first operand is Below second operand (as set by CMP instruction).
1675 Unsigned.
1676 <br><br>Algorithm:<br><br>
1677 <font face="Fixedsys">
1678 <ul>
1679         if CF = 1 then jump
1680 </ul>
1681 </font>
1682 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
1683
1684    ORG 100h
1685    MOV AL, 1
1686    CMP AL, 5
1687    JB  label1
1688    PRINT 'AL is not below 5'
1689    JMP exit
1690 label1:
1691    PRINT 'AL is below 5'
1692 exit:
1693    RET</font></pre>
1694
1695 <font face="Fixedsys">
1696 <table noshade="" border="1">
1697 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
1698 <tr> <td colspan="6">unchanged</td> </tr>
1699 </tbody></table>
1700 </font>
1701
1702 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1703
1704
1705                         <a name="JBE">&nbsp;</a>
1706 </td>
1707 </tr>
1708
1709
1710
1711
1712 <tr>
1713 <td>
1714 <font face="Fixedsys">
1715 JBE
1716 </font>
1717 </td>
1718 <td>
1719 <font face="Fixedsys">
1720         <nobr>label</nobr>
1721 </font>
1722 </td>
1723 <td>
1724
1725 Short Jump if first operand is Below or Equal to second operand (as set by CMP instruction).
1726 Unsigned.
1727 <br><br>Algorithm:<br><br>
1728 <font face="Fixedsys">
1729 <ul>
1730         if CF = 1 or ZF = 1 then jump
1731 </ul>
1732 </font>
1733 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
1734
1735    ORG 100h
1736    MOV AL, 5
1737    CMP AL, 5
1738    JBE  label1
1739    PRINT 'AL is not below or equal to 5'
1740    JMP exit
1741 label1:
1742    PRINT 'AL is below or equal to 5'
1743 exit:
1744    RET</font></pre>
1745
1746 <font face="Fixedsys">
1747 <table noshade="" border="1">
1748 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
1749 <tr> <td colspan="6">unchanged</td> </tr>
1750 </tbody></table>
1751 </font>
1752
1753 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1754
1755
1756                         <a name="JC">&nbsp;</a>
1757 </td>
1758 </tr>
1759
1760
1761
1762
1763 <tr>
1764 <td>
1765 <font face="Fixedsys">
1766 JC
1767 </font>
1768 </td>
1769 <td>
1770 <font face="Fixedsys">
1771         <nobr>label</nobr>
1772 </font>
1773 </td>
1774 <td>
1775
1776 Short Jump if Carry flag is set to 1.
1777 <br><br>Algorithm:<br><br>
1778 <font face="Fixedsys">
1779 </font><ul>
1780 <font face="Fixedsys">  if CF = 1 then jump
1781 </font></ul>
1782 <font face="Fixedsys"></font>
1783 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
1784
1785    ORG 100h
1786    MOV AL, 255
1787    ADD AL, 1
1788    JC  label1
1789    PRINT 'no carry.'
1790    JMP exit
1791 label1:
1792    PRINT 'has carry.'
1793 exit:
1794    RET</font></pre>
1795
1796 <font face="Fixedsys">
1797 <table noshade="" border="1">
1798 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
1799 <tr> <td colspan="6">unchanged</td> </tr>
1800 </tbody></table>
1801 </font>
1802
1803 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1804
1805
1806                         <a name="JCXZ">&nbsp;</a>
1807 </td>
1808 </tr>
1809
1810
1811
1812
1813 <tr>
1814 <td>
1815 <font face="Fixedsys">
1816 JCXZ
1817 </font>
1818 </td>
1819 <td>
1820 <font face="Fixedsys">
1821         <nobr>label</nobr>
1822 </font>
1823 </td>
1824 <td>
1825
1826 Short Jump if CX register is 0.
1827 <br><br>Algorithm:<br><br>
1828 <font face="Fixedsys">
1829 <ul>
1830         if CX = 0 then jump
1831 </ul>
1832 </font>
1833 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
1834
1835    ORG 100h
1836    MOV CX, 0
1837    JCXZ label1
1838    PRINT 'CX is not zero.'
1839    JMP exit
1840 label1:
1841    PRINT 'CX is zero.'
1842 exit:
1843    RET</font></pre>
1844
1845 <font face="Fixedsys">
1846 <table noshade="" border="1">
1847 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
1848 <tr> <td colspan="6">unchanged</td> </tr>
1849 </tbody></table>
1850 </font>
1851
1852 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1853
1854
1855                         <a name="JE">&nbsp;</a>
1856 </td>
1857 </tr>
1858
1859
1860
1861
1862 <tr>
1863 <td>
1864 <font face="Fixedsys">
1865 JE
1866 </font>
1867 </td>
1868 <td>
1869 <font face="Fixedsys">
1870         <nobr>label</nobr>
1871 </font>
1872 </td>
1873 <td>
1874
1875 Short Jump if first operand is Equal to second operand (as set by CMP instruction).
1876 Signed/Unsigned.
1877 <br><br>Algorithm:<br><br>
1878 <font face="Fixedsys">
1879 <ul>
1880         if ZF = 1 then jump
1881 </ul>
1882 </font>
1883 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
1884
1885    ORG 100h
1886    MOV AL, 5
1887    CMP AL, 5
1888    JE  label1
1889    PRINT 'AL is not equal to 5.'
1890    JMP exit
1891 label1:
1892    PRINT 'AL is equal to 5.'
1893 exit:
1894    RET</font></pre>
1895
1896 <font face="Fixedsys">
1897 <table noshade="" border="1">
1898 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
1899 <tr> <td colspan="6">unchanged</td> </tr>
1900 </tbody></table>
1901 </font>
1902
1903 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1904
1905
1906                         <a name="JG">&nbsp;</a>
1907 </td>
1908 </tr>
1909
1910
1911
1912
1913 <tr>
1914 <td>
1915 <font face="Fixedsys">
1916 JG
1917 </font>
1918 </td>
1919 <td>
1920 <font face="Fixedsys">
1921         <nobr>label</nobr>
1922 </font>
1923 </td>
1924 <td>
1925
1926 Short Jump if first operand is Greater then second operand (as set by CMP instruction).
1927 Signed.
1928 <br><br>Algorithm:<br><br>
1929 <font face="Fixedsys">
1930 <ul>
1931         if (ZF = 0) and (SF = OF) then jump
1932 </ul>
1933 </font>
1934 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
1935
1936    ORG 100h
1937    MOV AL, 5
1938    CMP AL, -5
1939    JG  label1
1940    PRINT 'AL is not greater -5.'
1941    JMP exit
1942 label1:
1943    PRINT 'AL is greater -5.'
1944 exit:
1945    RET</font></pre>
1946
1947 <font face="Fixedsys">
1948 <table noshade="" border="1">
1949 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
1950 <tr> <td colspan="6">unchanged</td> </tr>
1951 </tbody></table>
1952 </font>
1953
1954 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
1955
1956
1957                         <a name="JGE">&nbsp;</a>
1958 </td>
1959 </tr>
1960
1961
1962
1963
1964 <tr>
1965 <td>
1966 <font face="Fixedsys">
1967 JGE
1968 </font>
1969 </td>
1970 <td>
1971 <font face="Fixedsys">
1972         <nobr>label</nobr>
1973 </font>
1974 </td>
1975 <td>
1976
1977 Short Jump if first operand is Greater or Equal to second operand (as set by CMP instruction).
1978 Signed.
1979 <br><br>Algorithm:<br><br>
1980 <font face="Fixedsys">
1981 <ul>
1982         if SF = OF then jump
1983 </ul>
1984 </font>
1985 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
1986
1987    ORG 100h
1988    MOV AL, 2
1989    CMP AL, -5
1990    JGE  label1
1991    PRINT 'AL &lt; -5'
1992    JMP exit
1993 label1:
1994    PRINT 'AL &gt;= -5'
1995 exit:
1996    RET</font></pre>
1997
1998 <font face="Fixedsys">
1999 <table noshade="" border="1">
2000 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2001 <tr> <td colspan="6">unchanged</td> </tr>
2002 </tbody></table>
2003 </font>
2004
2005 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2006
2007
2008                         <a name="JL">&nbsp;</a>
2009 </td>
2010 </tr>
2011
2012
2013
2014
2015 <tr>
2016 <td>
2017 <font face="Fixedsys">
2018 JL
2019 </font>
2020 </td>
2021 <td>
2022 <font face="Fixedsys">
2023         <nobr>label</nobr>
2024 </font>
2025 </td>
2026 <td>
2027
2028 Short Jump if first operand is Less then second operand (as set by CMP instruction).
2029 Signed.
2030 <br><br>Algorithm:<br><br>
2031 <font face="Fixedsys">
2032 <ul>
2033         if SF &lt;&gt; OF then jump
2034 </ul>
2035 </font>
2036 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
2037
2038    ORG 100h
2039    MOV AL, -2
2040    CMP AL, 5
2041    JL  label1
2042    PRINT 'AL &gt;= 5.'
2043    JMP exit
2044 label1:
2045    PRINT 'AL &lt; 5.'
2046 exit:
2047    RET</font></pre>
2048
2049 <font face="Fixedsys">
2050 <table noshade="" border="1">
2051 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2052 <tr> <td colspan="6">unchanged</td> </tr>
2053 </tbody></table>
2054 </font>
2055
2056 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2057
2058
2059                         <a name="JLE">&nbsp;</a>
2060 </td>
2061 </tr>
2062
2063
2064
2065
2066 <tr>
2067 <td>
2068 <font face="Fixedsys">
2069 JLE
2070 </font>
2071 </td>
2072 <td>
2073 <font face="Fixedsys">
2074         <nobr>label</nobr>
2075 </font>
2076 </td>
2077 <td>
2078
2079 Short Jump if first operand is Less or Equal to second operand (as set by CMP instruction).
2080 Signed.
2081 <br><br>Algorithm:<br><br>
2082 <font face="Fixedsys">
2083 <ul>
2084         if SF &lt;&gt; OF or ZF = 1 then jump
2085 </ul>
2086 </font>
2087 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
2088
2089    ORG 100h
2090    MOV AL, -2
2091    CMP AL, 5
2092    JLE label1
2093    PRINT 'AL &gt; 5.'
2094    JMP exit
2095 label1:
2096    PRINT 'AL &lt;= 5.'
2097 exit:
2098    RET</font></pre>
2099
2100 <font face="Fixedsys">
2101 <table noshade="" border="1">
2102 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2103 <tr> <td colspan="6">unchanged</td> </tr>
2104 </tbody></table>
2105 </font>
2106
2107 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2108
2109
2110                         <a name="JMP">&nbsp;</a>
2111 </td>
2112 </tr>
2113
2114
2115
2116
2117 <tr>
2118 <td>
2119 <font face="Fixedsys">
2120 JMP
2121 </font>
2122 </td>
2123 <td>
2124 <font face="Fixedsys">
2125         <nobr>
2126         label<br>
2127         4-byte address<br>
2128         </nobr>
2129 </font>
2130 </td>
2131 <td>
2132
2133 Unconditional Jump.
2134 Transfers control to another part of the program.
2135 <i>4-byte address</i> may be entered in this form:
2136 <font face="Fixedsys">1234h:5678h</font>, first value is a segment second
2137 value is an offset.<br>
2138
2139 <br><br>Algorithm:<br><br>
2140 <font face="Fixedsys">
2141 <ul>
2142         always jump
2143 </ul>
2144 </font>
2145 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
2146
2147    ORG 100h
2148    MOV AL, 5
2149    JMP label1    ; jump over 2 lines!
2150    PRINT 'Not Jumped!'
2151    MOV AL, 0
2152 label1:
2153    PRINT 'Got Here!'
2154    RET</font></pre>
2155
2156 <font face="Fixedsys">
2157 <table noshade="" border="1">
2158 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2159 <tr> <td colspan="6">unchanged</td> </tr>
2160 </tbody></table>
2161 </font>
2162
2163 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2164
2165
2166                         <a name="JNA">&nbsp;</a>
2167 </td>
2168 </tr>
2169
2170
2171
2172
2173 <tr>
2174 <td>
2175 <font face="Fixedsys">
2176 JNA
2177 </font>
2178 </td>
2179 <td>
2180 <font face="Fixedsys">
2181         <nobr>label</nobr>
2182 </font>
2183 </td>
2184 <td>
2185
2186 Short Jump if first operand is Not Above second operand (as set by CMP instruction).
2187 Unsigned.
2188 <br><br>Algorithm:<br><br>
2189 <font face="Fixedsys">
2190 <ul>
2191         if CF = 1 or ZF = 1 then jump
2192 </ul>
2193 </font>
2194 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
2195
2196    ORG 100h
2197    MOV AL, 2
2198    CMP AL, 5
2199    JNA label1
2200    PRINT 'AL is above 5.'
2201    JMP exit
2202 label1:
2203    PRINT 'AL is not above 5.'
2204 exit:
2205    RET</font></pre>
2206
2207 <font face="Fixedsys">
2208 <table noshade="" border="1">
2209 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2210 <tr> <td colspan="6">unchanged</td> </tr>
2211 </tbody></table>
2212 </font>
2213
2214 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2215
2216
2217                         <a name="JNAE">&nbsp;</a>
2218 </td>
2219 </tr>
2220
2221
2222
2223
2224 <tr>
2225 <td>
2226 <font face="Fixedsys">
2227 JNAE
2228 </font>
2229 </td>
2230 <td>
2231 <font face="Fixedsys">
2232         <nobr>label</nobr>
2233 </font>
2234 </td>
2235 <td>
2236
2237 Short Jump if first operand is Not Above and Not Equal to second operand (as set by CMP instruction).
2238 Unsigned.
2239 <br><br>Algorithm:<br><br>
2240 <font face="Fixedsys">
2241 <ul>
2242         if CF = 1 then jump
2243 </ul>
2244 </font>
2245 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
2246
2247    ORG 100h
2248    MOV AL, 2
2249    CMP AL, 5
2250    JNAE label1
2251    PRINT 'AL &gt;= 5.'
2252    JMP exit
2253 label1:
2254    PRINT 'AL &lt; 5.'
2255 exit:
2256    RET</font></pre>
2257
2258 <font face="Fixedsys">
2259 <table noshade="" border="1">
2260 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2261 <tr> <td colspan="6">unchanged</td> </tr>
2262 </tbody></table>
2263 </font>
2264
2265 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2266
2267
2268                         <a name="JNB">&nbsp;</a>
2269 </td>
2270 </tr>
2271
2272
2273
2274
2275 <tr>
2276 <td>
2277 <font face="Fixedsys">
2278 JNB
2279 </font>
2280 </td>
2281 <td>
2282 <font face="Fixedsys">
2283         <nobr>label</nobr>
2284 </font>
2285 </td>
2286 <td>
2287
2288 Short Jump if first operand is Not Below second operand (as set by CMP instruction).
2289 Unsigned.
2290 <br><br>Algorithm:<br><br>
2291 <font face="Fixedsys">
2292 <ul>
2293         if CF = 0 then jump
2294 </ul>
2295 </font>
2296 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
2297
2298    ORG 100h
2299    MOV AL, 7
2300    CMP AL, 5
2301    JNB label1
2302    PRINT 'AL &lt; 5.'
2303    JMP exit
2304 label1:
2305    PRINT 'AL &gt;= 5.'
2306 exit:
2307    RET</font></pre>
2308
2309 <font face="Fixedsys">
2310 <table noshade="" border="1">
2311 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2312 <tr> <td colspan="6">unchanged</td> </tr>
2313 </tbody></table>
2314 </font>
2315
2316 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2317
2318
2319                         <a name="JNBE">&nbsp;</a>
2320 </td>
2321 </tr>
2322
2323
2324
2325
2326 <tr>
2327 <td>
2328 <font face="Fixedsys">
2329 JNBE
2330 </font>
2331 </td>
2332 <td>
2333 <font face="Fixedsys">
2334         <nobr>label</nobr>
2335 </font>
2336 </td>
2337 <td>
2338
2339 Short Jump if first operand is Not Below and Not Equal to second operand (as set by CMP instruction).
2340 Unsigned.
2341 <br><br>Algorithm:<br><br>
2342 <font face="Fixedsys">
2343 <ul>
2344         if (CF = 0) and (ZF = 0) then jump
2345 </ul>
2346 </font>
2347 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
2348
2349    ORG 100h
2350    MOV AL, 7
2351    CMP AL, 5
2352    JNBE label1
2353    PRINT 'AL &lt;= 5.'
2354    JMP exit
2355 label1:
2356    PRINT 'AL &gt; 5.'
2357 exit:
2358    RET</font></pre>
2359
2360 <font face="Fixedsys">
2361 <table noshade="" border="1">
2362 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2363 <tr> <td colspan="6">unchanged</td> </tr>
2364 </tbody></table>
2365 </font>
2366
2367 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2368
2369
2370                         <a name="JNC">&nbsp;</a>
2371 </td>
2372 </tr>
2373
2374
2375
2376
2377 <tr>
2378 <td>
2379 <font face="Fixedsys">
2380 JNC
2381 </font>
2382 </td>
2383 <td>
2384 <font face="Fixedsys">
2385         <nobr>label</nobr>
2386 </font>
2387 </td>
2388 <td>
2389
2390 Short Jump if Carry flag is set to 0.
2391 <br><br>Algorithm:<br><br>
2392 <font face="Fixedsys">
2393 <ul>
2394         if CF = 0 then jump
2395 </ul>
2396 </font>
2397 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
2398
2399    ORG 100h
2400    MOV AL, 2
2401    ADD AL, 3
2402    JNC  label1
2403    PRINT 'has carry.'
2404    JMP exit
2405 label1:
2406    PRINT 'no carry.'
2407 exit:
2408    RET</font></pre>
2409
2410 <font face="Fixedsys">
2411 <table noshade="" border="1">
2412 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2413 <tr> <td colspan="6">unchanged</td> </tr>
2414 </tbody></table>
2415 </font>
2416
2417 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2418
2419
2420                         <a name="JNE">&nbsp;</a>
2421 </td>
2422 </tr>
2423
2424
2425
2426
2427 <tr>
2428 <td>
2429 <font face="Fixedsys">
2430 JNE
2431 </font>
2432 </td>
2433 <td>
2434 <font face="Fixedsys">
2435         <nobr>label</nobr>
2436 </font>
2437 </td>
2438 <td>
2439
2440 Short Jump if first operand is Not Equal to second operand (as set by CMP instruction).
2441 Signed/Unsigned.
2442 <br><br>Algorithm:<br><br>
2443 <font face="Fixedsys">
2444 <ul>
2445         if ZF = 0 then jump
2446 </ul>
2447 </font>
2448 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
2449
2450    ORG 100h
2451    MOV AL, 2
2452    CMP AL, 3
2453    JNE  label1
2454    PRINT 'AL = 3.'
2455    JMP exit
2456 label1:
2457    PRINT 'Al &lt;&gt; 3.'
2458 exit:
2459    RET</font></pre>
2460
2461 <font face="Fixedsys">
2462 <table noshade="" border="1">
2463 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2464 <tr> <td colspan="6">unchanged</td> </tr>
2465 </tbody></table>
2466 </font>
2467
2468 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2469
2470
2471                         <a name="JNG">&nbsp;</a>
2472 </td>
2473 </tr>
2474
2475
2476
2477
2478 <tr>
2479 <td>
2480 <font face="Fixedsys">
2481 JNG
2482 </font>
2483 </td>
2484 <td>
2485 <font face="Fixedsys">
2486         <nobr>label</nobr>
2487 </font>
2488 </td>
2489 <td>
2490
2491 Short Jump if first operand is Not Greater then second operand (as set by CMP instruction).
2492 Signed.
2493 <br><br>Algorithm:<br><br>
2494 <font face="Fixedsys">
2495 <ul>
2496         if (ZF = 1) and (SF &lt;&gt; OF) then jump
2497 </ul>
2498 </font>
2499 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
2500
2501    ORG 100h
2502    MOV AL, 2
2503    CMP AL, 3
2504    JNG  label1
2505    PRINT 'AL &gt; 3.'
2506    JMP exit
2507 label1:
2508    PRINT 'Al &lt;= 3.'
2509 exit:
2510    RET</font></pre>
2511
2512 <font face="Fixedsys">
2513 <table noshade="" border="1">
2514 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2515 <tr> <td colspan="6">unchanged</td> </tr>
2516 </tbody></table>
2517 </font>
2518
2519 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2520
2521
2522                         <a name="JNGE">&nbsp;</a>
2523 </td>
2524 </tr>
2525
2526
2527
2528
2529 <tr>
2530 <td>
2531 <font face="Fixedsys">
2532 JNGE
2533 </font>
2534 </td>
2535 <td>
2536 <font face="Fixedsys">
2537         <nobr>label</nobr>
2538 </font>
2539 </td>
2540 <td>
2541
2542 Short Jump if first operand is Not Greater and Not Equal to second operand (as set by CMP instruction).
2543 Signed.
2544 <br><br>Algorithm:<br><br>
2545 <font face="Fixedsys">
2546 <ul>
2547         if SF &lt;&gt; OF then jump
2548 </ul>
2549 </font>
2550 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
2551
2552    ORG 100h
2553    MOV AL, 2
2554    CMP AL, 3
2555    JNGE  label1
2556    PRINT 'AL &gt;= 3.'
2557    JMP exit
2558 label1:
2559    PRINT 'Al &lt; 3.'
2560 exit:
2561    RET</font></pre>
2562
2563 <font face="Fixedsys">
2564 <table noshade="" border="1">
2565 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2566 <tr> <td colspan="6">unchanged</td> </tr>
2567 </tbody></table>
2568 </font>
2569
2570 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2571
2572
2573                         <a name="JNL">&nbsp;</a>
2574 </td>
2575 </tr>
2576
2577
2578
2579
2580 <tr>
2581 <td>
2582 <font face="Fixedsys">
2583 JNL
2584 </font>
2585 </td>
2586 <td>
2587 <font face="Fixedsys">
2588         <nobr>label</nobr>
2589 </font>
2590 </td>
2591 <td>
2592
2593 Short Jump if first operand is Not Less then second operand (as set by CMP instruction).
2594 Signed.
2595 <br><br>Algorithm:<br><br>
2596 <font face="Fixedsys">
2597 <ul>
2598         if SF = OF then jump
2599 </ul>
2600 </font>
2601 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
2602
2603    ORG 100h
2604    MOV AL, 2
2605    CMP AL, -3
2606    JNL label1
2607    PRINT 'AL &lt; -3.'
2608    JMP exit
2609 label1:
2610    PRINT 'Al &gt;= -3.'
2611 exit:
2612    RET</font></pre>
2613
2614 <font face="Fixedsys">
2615 <table noshade="" border="1">
2616 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2617 <tr> <td colspan="6">unchanged</td> </tr>
2618 </tbody></table>
2619 </font>
2620
2621 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2622
2623
2624                         <a name="JNLE">&nbsp;</a>
2625 </td>
2626 </tr>
2627
2628
2629
2630
2631 <tr>
2632 <td>
2633 <font face="Fixedsys">
2634 JNLE
2635 </font>
2636 </td>
2637 <td>
2638 <font face="Fixedsys">
2639         <nobr>label</nobr>
2640 </font>
2641 </td>
2642 <td>
2643
2644 Short Jump if first operand is Not Less and Not Equal to second operand (as set by CMP instruction).
2645 Signed.
2646 <br><br>Algorithm:<br><br>
2647 <font face="Fixedsys">
2648 <ul>
2649         if (SF = OF) and (ZF = 0) then jump
2650 </ul>
2651 </font>
2652 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
2653
2654    ORG 100h
2655    MOV AL, 2
2656    CMP AL, -3
2657    JNLE label1
2658    PRINT 'AL &lt;= -3.'
2659    JMP exit
2660 label1:
2661    PRINT 'Al &gt; -3.'
2662 exit:
2663    RET</font></pre>
2664
2665 <font face="Fixedsys">
2666 <table noshade="" border="1">
2667 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2668 <tr> <td colspan="6">unchanged</td> </tr>
2669 </tbody></table>
2670 </font>
2671
2672 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2673
2674
2675                         <a name="JNO">&nbsp;</a>
2676 </td>
2677 </tr>
2678
2679
2680
2681
2682 <tr>
2683 <td>
2684 <font face="Fixedsys">
2685 JNO
2686 </font>
2687 </td>
2688 <td>
2689 <font face="Fixedsys">
2690         <nobr>label</nobr>
2691 </font>
2692 </td>
2693 <td>
2694
2695 Short Jump if Not Overflow.
2696 <br><br>Algorithm:<br><br>
2697 <font face="Fixedsys">
2698 <ul>
2699         if OF = 0 then jump
2700 </ul>
2701 </font>
2702 Example:<pre><font face="Fixedsys">; -5 - 2 = -7 (inside -128..127)
2703 ; the result of SUB is correct,
2704 ; so OF = 0:
2705
2706 include 'emu8086.inc'
2707
2708 ORG 100h
2709   MOV AL, -5
2710   SUB AL, 2   ; AL = 0F9h (-7)
2711 JNO  label1
2712   PRINT 'overflow!'
2713 JMP exit
2714 label1:
2715   PRINT 'no overflow.'
2716 exit:
2717   RET</font></pre>
2718
2719 <font face="Fixedsys">
2720 <table noshade="" border="1">
2721 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2722 <tr> <td colspan="6">unchanged</td> </tr>
2723 </tbody></table>
2724 </font>
2725
2726 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2727
2728
2729                         <a name="JNP">&nbsp;</a>
2730 </td>
2731 </tr>
2732
2733
2734
2735
2736 <tr>
2737 <td>
2738 <font face="Fixedsys">
2739 JNP
2740 </font>
2741 </td>
2742 <td>
2743 <font face="Fixedsys">
2744         <nobr>label</nobr>
2745 </font>
2746 </td>
2747 <td>
2748
2749 Short Jump if No Parity (odd). Only 8 low bits of result are checked.
2750 Set by CMP, SUB, ADD, TEST, AND, OR, XOR instructions.
2751 <br><br>Algorithm:<br><br>
2752 <font face="Fixedsys">
2753 <ul>
2754         if PF = 0 then jump
2755 </ul>
2756 </font>
2757 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
2758
2759    ORG 100h
2760    MOV AL, 00000111b   ; AL = 7
2761    OR  AL, 0           ; just set flags.
2762    JNP label1
2763    PRINT 'parity even.'
2764    JMP exit
2765 label1:
2766    PRINT 'parity odd.'
2767 exit:
2768    RET</font></pre>
2769
2770 <font face="Fixedsys">
2771 <table noshade="" border="1">
2772 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2773 <tr> <td colspan="6">unchanged</td> </tr>
2774 </tbody></table>
2775 </font>
2776
2777 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2778
2779
2780                         <a name="JNS">&nbsp;</a>
2781 </td>
2782 </tr>
2783
2784
2785
2786
2787 <tr>
2788 <td>
2789 <font face="Fixedsys">
2790 JNS
2791 </font>
2792 </td>
2793 <td>
2794 <font face="Fixedsys">
2795         <nobr>label</nobr>
2796 </font>
2797 </td>
2798 <td>
2799
2800 Short Jump if Not Signed (if positive).
2801 Set by CMP, SUB, ADD, TEST, AND, OR, XOR instructions.
2802 <br><br>Algorithm:<br><br>
2803 <font face="Fixedsys">
2804 <ul>
2805         if SF = 0 then jump
2806 </ul>
2807 </font>
2808 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
2809
2810    ORG 100h
2811    MOV AL, 00000111b   ; AL = 7
2812    OR  AL, 0           ; just set flags.
2813    JNS label1
2814    PRINT 'signed.'
2815    JMP exit
2816 label1:
2817    PRINT 'not signed.'
2818 exit:
2819    RET</font></pre>
2820
2821 <font face="Fixedsys">
2822 <table noshade="" border="1">
2823 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2824 <tr> <td colspan="6">unchanged</td> </tr>
2825 </tbody></table>
2826 </font>
2827
2828 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2829
2830
2831                         <a name="JNZ">&nbsp;</a>
2832 </td>
2833 </tr>
2834
2835
2836
2837
2838 <tr>
2839 <td>
2840 <font face="Fixedsys">
2841 JNZ
2842 </font>
2843 </td>
2844 <td>
2845 <font face="Fixedsys">
2846         <nobr>label</nobr>
2847 </font>
2848 </td>
2849 <td>
2850
2851 Short Jump if Not Zero (not equal).
2852 Set by CMP, SUB, ADD, TEST, AND, OR, XOR instructions.
2853 <br><br>Algorithm:<br><br>
2854 <font face="Fixedsys">
2855 <ul>
2856         if ZF = 0 then jump
2857 </ul>
2858 </font>
2859 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
2860
2861    ORG 100h
2862    MOV AL, 00000111b   ; AL = 7
2863    OR  AL, 0           ; just set flags.
2864    JNZ label1
2865    PRINT 'zero.'
2866    JMP exit
2867 label1:
2868    PRINT 'not zero.'
2869 exit:
2870    RET</font></pre>
2871
2872 <font face="Fixedsys">
2873 <table noshade="" border="1">
2874 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2875 <tr> <td colspan="6">unchanged</td> </tr>
2876 </tbody></table>
2877 </font>
2878
2879 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2880
2881
2882                         <a name="JO">&nbsp;</a>
2883 </td>
2884 </tr>
2885
2886
2887
2888
2889 <tr>
2890 <td>
2891 <font face="Fixedsys">
2892 JO
2893 </font>
2894 </td>
2895 <td>
2896 <font face="Fixedsys">
2897         <nobr>label</nobr>
2898 </font>
2899 </td>
2900 <td>
2901
2902 Short Jump if Overflow.
2903 <br><br>Algorithm:<br><br>
2904 <font face="Fixedsys">
2905 <ul>
2906         if OF = 1 then jump
2907 </ul>
2908 </font>
2909 Example:<pre><font face="Fixedsys">; -5 - 127 = -132 (not in -128..127)
2910 ; the result of SUB is wrong (124),
2911 ; so OF = 1 is set:
2912
2913 include 'emu8086.inc'
2914
2915 org 100h
2916   MOV AL, -5
2917   SUB AL, 127   ; AL = 7Ch (124)
2918 JO  label1
2919   PRINT 'no overflow.'
2920 JMP exit
2921 label1:
2922   PRINT 'overflow!'
2923 exit:
2924   RET</font></pre>
2925
2926 <font face="Fixedsys">
2927 <table noshade="" border="1">
2928 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2929 <tr> <td colspan="6">unchanged</td> </tr>
2930 </tbody></table>
2931 </font>
2932
2933 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2934
2935
2936                         <a name="JP">&nbsp;</a>
2937 </td>
2938 </tr>
2939
2940
2941
2942
2943 <tr>
2944 <td>
2945 <font face="Fixedsys">
2946 JP
2947 </font>
2948 </td>
2949 <td>
2950 <font face="Fixedsys">
2951         <nobr>label</nobr>
2952 </font>
2953 </td>
2954 <td>
2955
2956 Short Jump if Parity (even). Only 8 low bits of result are checked.
2957 Set by CMP, SUB, ADD, TEST, AND, OR, XOR instructions.
2958 <br><br>Algorithm:<br><br>
2959 <font face="Fixedsys">
2960 <ul>
2961         if PF = 1 then jump
2962 </ul>
2963 </font>
2964 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
2965
2966    ORG 100h
2967    MOV AL, 00000101b   ; AL = 5
2968    OR  AL, 0           ; just set flags.
2969    JP label1
2970    PRINT 'parity odd.'
2971    JMP exit
2972 label1:
2973    PRINT 'parity even.'
2974 exit:
2975    RET</font></pre>
2976
2977 <font face="Fixedsys">
2978 <table noshade="" border="1">
2979 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
2980 <tr> <td colspan="6">unchanged</td> </tr>
2981 </tbody></table>
2982 </font>
2983
2984 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
2985
2986
2987                         <a name="JPE">&nbsp;</a>
2988 </td>
2989 </tr>
2990
2991
2992
2993
2994 <tr>
2995 <td>
2996 <font face="Fixedsys">
2997 JPE
2998 </font>
2999 </td>
3000 <td>
3001 <font face="Fixedsys">
3002         <nobr>label</nobr>
3003 </font>
3004 </td>
3005 <td>
3006
3007 Short Jump if Parity Even. Only 8 low bits of result are checked.
3008 Set by CMP, SUB, ADD, TEST, AND, OR, XOR instructions.
3009 <br><br>Algorithm:<br><br>
3010 <font face="Fixedsys">
3011 <ul>
3012         if PF = 1 then jump
3013 </ul>
3014 </font>
3015 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
3016
3017    ORG 100h
3018    MOV AL, 00000101b   ; AL = 5
3019    OR  AL, 0           ; just set flags.
3020    JPE label1
3021    PRINT 'parity odd.'
3022    JMP exit
3023 label1:
3024    PRINT 'parity even.'
3025 exit:
3026    RET</font></pre>
3027
3028 <font face="Fixedsys">
3029 <table noshade="" border="1">
3030 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
3031 <tr> <td colspan="6">unchanged</td> </tr>
3032 </tbody></table>
3033 </font>
3034
3035 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
3036
3037
3038                         <a name="JPO">&nbsp;</a>
3039 </td>
3040 </tr>
3041
3042
3043
3044
3045 <tr>
3046 <td>
3047 <font face="Fixedsys">
3048 JPO
3049 </font>
3050 </td>
3051 <td>
3052 <font face="Fixedsys">
3053         <nobr>label</nobr>
3054 </font>
3055 </td>
3056 <td>
3057
3058 Short Jump if Parity Odd. Only 8 low bits of result are checked.
3059 Set by CMP, SUB, ADD, TEST, AND, OR, XOR instructions.
3060 <br><br>Algorithm:<br><br>
3061 <font face="Fixedsys">
3062 <ul>
3063         if PF = 0 then jump
3064 </ul>
3065 </font>
3066 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
3067
3068    ORG 100h
3069    MOV AL, 00000111b   ; AL = 7
3070    OR  AL, 0           ; just set flags.
3071    JPO label1
3072    PRINT 'parity even.'
3073    JMP exit
3074 label1:
3075    PRINT 'parity odd.'
3076 exit:
3077    RET</font></pre>
3078
3079 <font face="Fixedsys">
3080 <table noshade="" border="1">
3081 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
3082 <tr> <td colspan="6">unchanged</td> </tr>
3083 </tbody></table>
3084 </font>
3085
3086 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
3087
3088
3089                         <a name="JS">&nbsp;</a>
3090 </td>
3091 </tr>
3092
3093
3094
3095
3096 <tr>
3097 <td>
3098 <font face="Fixedsys">
3099 JS
3100 </font>
3101 </td>
3102 <td>
3103 <font face="Fixedsys">
3104         <nobr>label</nobr>
3105 </font>
3106 </td>
3107 <td>
3108
3109 Short Jump if Signed (if negative).
3110 Set by CMP, SUB, ADD, TEST, AND, OR, XOR instructions.
3111 <br><br>Algorithm:<br><br>
3112 <font face="Fixedsys">
3113 <ul>
3114         if SF = 1 then jump
3115 </ul>
3116 </font>
3117 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
3118
3119    ORG 100h
3120    MOV AL, 10000000b   ; AL = -128
3121    OR  AL, 0           ; just set flags.
3122    JS label1
3123    PRINT 'not signed.'
3124    JMP exit
3125 label1:
3126    PRINT 'signed.'
3127 exit:
3128    RET</font></pre>
3129
3130 <font face="Fixedsys">
3131 <table noshade="" border="1">
3132 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
3133 <tr> <td colspan="6">unchanged</td> </tr>
3134 </tbody></table>
3135 </font>
3136
3137 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
3138
3139
3140                         <a name="JZ">&nbsp;</a>
3141 </td>
3142 </tr>
3143
3144
3145
3146
3147 <tr>
3148 <td>
3149 <font face="Fixedsys">
3150 JZ
3151 </font>
3152 </td>
3153 <td>
3154 <font face="Fixedsys">
3155         <nobr>label</nobr>
3156 </font>
3157 </td>
3158 <td>
3159
3160 Short Jump if Zero (equal).
3161 Set by CMP, SUB, ADD, TEST, AND, OR, XOR instructions.
3162 <br><br>Algorithm:<br><br>
3163 <font face="Fixedsys">
3164 <ul>
3165         if ZF = 1 then jump
3166 </ul>
3167 </font>
3168 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
3169
3170    ORG 100h
3171    MOV AL, 5
3172    CMP AL, 5
3173    JZ  label1
3174    PRINT 'AL is not equal to 5.'
3175    JMP exit
3176 label1:
3177    PRINT 'AL is equal to 5.'
3178 exit:
3179    RET</font></pre>
3180
3181 <font face="Fixedsys">
3182 <table noshade="" border="1">
3183 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
3184 <tr> <td colspan="6">unchanged</td> </tr>
3185 </tbody></table>
3186 </font>
3187
3188 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
3189
3190
3191                         <a name="LAHF">&nbsp;</a>
3192 </td>
3193 </tr>
3194
3195
3196
3197
3198 <tr>
3199 <td>
3200 <font face="Fixedsys">
3201 LAHF
3202 </font>
3203 </td>
3204 <td>No operands</td>
3205 <td>
3206
3207 Load AH from 8 low bits of Flags register.
3208 <br><br>Algorithm:<br><br>
3209 <font face="Fixedsys">
3210 </font><ul>
3211 <font face="Fixedsys">  AH = flags register<br>
3212 </font></ul>
3213 <pre><font face="Fixedsys"><font face="Fixedsys">
3214 AH bit:   7    6   5    4   3    2   1    0
3215         [SF] [ZF] [0] [AF] [0] [PF] [1] [CF]</font>
3216 </font></pre>
3217 <font face="Fixedsys">bits 1, 3, 5 are reserved.
3218 </font>
3219
3220 <br><br>
3221
3222 <font face="Fixedsys">
3223 <table noshade="" border="1">
3224 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
3225 <tr> <td colspan="6">unchanged</td> </tr>
3226 </tbody></table>
3227 </font>
3228
3229 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
3230
3231
3232                         <a name="LDS">&nbsp;</a>
3233 </td>
3234 </tr>
3235
3236
3237
3238
3239 <tr>
3240 <td>
3241 <font face="Fixedsys">
3242 LDS
3243 </font>
3244 </td>
3245 <td>
3246 <font face="Fixedsys">
3247         <nobr>
3248         REG, memory
3249         </nobr>
3250 </font>
3251 </td>
3252 <td>
3253
3254 Load memory double word into word register and DS.
3255 <br><br>Algorithm:<br><br>
3256 <font face="Fixedsys">
3257 <ul>
3258     <li>REG = first word</li>
3259         <li>DS = second word</li>
3260 </ul>
3261 </font>
3262 <br>
3263 Example:
3264 <pre><font face="Fixedsys">
3265
3266 ORG 100h
3267
3268 LDS AX, m
3269
3270 RET
3271
3272 m  DW  1234h
3273    DW  5678h
3274
3275 END
3276 </font>
3277 </pre>
3278 AX is set to 1234h, DS is set to 5678h.
3279 <br><br>
3280
3281 <font face="Fixedsys">
3282 <table noshade="" border="1">
3283 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
3284 <tr> <td colspan="6">unchanged</td> </tr>
3285 </tbody></table>
3286 </font>
3287
3288 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
3289
3290
3291                         <a name="LEA">&nbsp;</a>
3292 </td>
3293 </tr>
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309 <tr>
3310 <td>
3311 <font face="Fixedsys">
3312 LEA
3313 </font>
3314 </td>
3315 <td>
3316 <font face="Fixedsys">
3317         <nobr>
3318         REG, memory
3319         </nobr>
3320 </font>
3321 </td>
3322 <td>
3323
3324 Load Effective Address.
3325 <br><br>Algorithm:<br><br>
3326 <font face="Fixedsys">
3327 <ul>
3328     <li>REG = address of memory (offset)</li>
3329 </ul>
3330 </font>
3331 <br>
3332 Example:
3333 <!-- START AUTOMATIC ASM TO HTML EXPORT -->
3334 <pre><font size="3" face="Terminal">
3335 <font color="#0000ff">MOV</font> <font color="#c80000">BX</font>, 35h
3336 <font color="#0000ff">MOV</font> <font color="#c80000">DI</font>, 12h
3337 <font color="#0000ff">LEA</font> <font color="#c80000">SI</font>, <font color="#0064c8">[</font><font color="#c80000">BX</font><font color="#0064c8">+</font><font color="#c80000">DI</font><font color="#0064c8">]</font>    <font color="#008000">; SI = 35h + 12h = 47h </font>
3338 </font></pre>
3339 <!-- emu8086 version 4.00-Beta-19    -->
3340 <!-- STOP AUTOMATIC ASM TO HTML EXPORT -->
3341
3342 Note: The integrated 8086 assembler automatically replaces <b>LEA</b> with a
3343 more efficient <b>MOV</b> where possible.
3344 For example:
3345 <!-- START AUTOMATIC ASM TO HTML EXPORT -->
3346 <pre><font size="3" face="Terminal">
3347 <font color="#000064">org</font> 100h
3348 <font color="#0000ff">LEA</font> <font color="#c80000">AX</font>, m       <font color="#008000">; AX = offset of m </font>
3349 <font color="#0000ff">RET</font>
3350 m  <font color="#000064">dw</font>  1234h
3351 <font color="#000064">END</font>
3352 </font></pre>
3353 <!-- emu8086 version 4.00-Beta-19    -->
3354 <!-- STOP AUTOMATIC ASM TO HTML EXPORT -->
3355 <br><br>
3356
3357 <font face="Fixedsys">
3358 <table noshade="" border="1">
3359 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
3360 <tr> <td colspan="6">unchanged</td> </tr>
3361 </tbody></table>
3362 </font>
3363
3364 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
3365
3366
3367                         <a name="LES">&nbsp;</a>
3368 </td>
3369 </tr>
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388 <tr>
3389 <td>
3390 <font face="Fixedsys">
3391 LES
3392 </font>
3393 </td>
3394 <td>
3395 <font face="Fixedsys">
3396         <nobr>
3397         REG, memory
3398         </nobr>
3399 </font>
3400 </td>
3401 <td>
3402
3403 Load memory double word into word register and ES.
3404 <br><br>Algorithm:<br><br>
3405 <font face="Fixedsys">
3406 <ul>
3407     <li>REG = first word</li>
3408         <li>ES = second word</li>
3409 </ul>
3410 </font>
3411 <br>
3412 Example:
3413 <pre><font face="Fixedsys">
3414
3415 ORG 100h
3416
3417 LES AX, m
3418
3419 RET
3420
3421 m  DW  1234h
3422    DW  5678h
3423
3424 END
3425 </font>
3426 </pre>
3427 AX is set to 1234h, ES is set to 5678h.
3428
3429 <br><br>
3430
3431 <font face="Fixedsys">
3432 <table noshade="" border="1">
3433 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
3434 <tr> <td colspan="6">unchanged</td> </tr>
3435 </tbody></table>
3436 </font>
3437
3438 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
3439
3440
3441
3442                         <a name="LODSB">&nbsp;</a>
3443 </td>
3444 </tr>
3445
3446
3447
3448
3449 <tr>
3450 <td>
3451 <font face="Fixedsys">
3452 LODSB
3453 </font>
3454 </td>
3455 <td>No operands</td>
3456 <td>
3457
3458 Load byte at DS:[SI] into AL. Update SI.<br><br>Algorithm:
3459 <br><br>
3460 <font face="Fixedsys">
3461 <ul>
3462 <li>AL = DS:[SI]<br></li>
3463 <li>if DF = 0 then
3464         <ul>
3465         <li>SI = SI + 1</li>
3466         </ul>
3467         else
3468         <ul>
3469         <li>SI = SI - 1</li>
3470         </ul>
3471 </li>
3472 </ul>
3473 </font>
3474 Example:
3475 <pre><font face="Fixedsys">
3476 ORG 100h
3477
3478 LEA SI, a1
3479 MOV CX, 5
3480 MOV AH, 0Eh
3481
3482 m: LODSB
3483 INT 10h
3484 LOOP m
3485
3486 RET
3487
3488 a1 DB 'H', 'e', 'l', 'l', 'o'</font></pre>
3489
3490 <font face="Fixedsys">
3491 <table noshade="" border="1">
3492 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
3493 <tr> <td colspan="6">unchanged</td> </tr>
3494 </tbody></table>
3495 </font>
3496
3497 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
3498
3499
3500                         <a name="LODSW">&nbsp;</a>
3501 </td>
3502 </tr>
3503
3504
3505
3506
3507 <tr>
3508 <td>
3509 <font face="Fixedsys">
3510 LODSW
3511 </font>
3512 </td>
3513 <td>No operands</td>
3514 <td>
3515
3516 Load word at DS:[SI] into AX. Update SI.<br><br>Algorithm:
3517 <br><br>
3518 <font face="Fixedsys">
3519 <ul>
3520 <li>AX = DS:[SI]<br></li>
3521 <li>if DF = 0 then
3522         <ul>
3523         <li>SI = SI + 2</li>
3524         </ul>
3525         else
3526         <ul>
3527         <li>SI = SI - 2</li>
3528         </ul>
3529 </li>
3530 </ul>
3531 </font>
3532 Example:
3533 <pre><font face="Fixedsys">
3534 ORG 100h
3535
3536 LEA SI, a1
3537 MOV CX, 5
3538
3539 REP LODSW   ; finally there will be 555h in AX.
3540
3541 RET
3542
3543 a1 dw 111h, 222h, 333h, 444h, 555h</font></pre>
3544
3545 <font face="Fixedsys">
3546 <table noshade="" border="1">
3547 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
3548 <tr> <td colspan="6">unchanged</td> </tr>
3549 </tbody></table>
3550 </font>
3551
3552 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
3553
3554
3555                         <a name="LOOP">&nbsp;</a>
3556 </td>
3557 </tr>
3558
3559
3560
3561
3562 <tr>
3563 <td>
3564 <font face="Fixedsys">
3565 LOOP
3566 </font>
3567 </td>
3568 <td>
3569 <font face="Fixedsys">
3570         <nobr>label</nobr>
3571 </font>
3572 </td>
3573 <td>
3574
3575 Decrease CX, jump to label if CX not zero. <br><br>Algorithm:
3576 <br><br>
3577 <font face="Fixedsys">
3578 <ul>
3579 <li>CX = CX - 1<br></li>
3580 <li>if CX &lt;&gt; 0 then
3581         <ul>
3582         <li>jump</li>
3583         </ul>
3584         else
3585         <ul>
3586         <li>no jump, continue</li>
3587         </ul>
3588 </li>
3589 </ul>
3590 </font>
3591 Example:<pre><font face="Fixedsys">   include 'emu8086.inc'
3592
3593    ORG 100h
3594    MOV CX, 5
3595 label1:
3596    PRINTN 'loop!'
3597    LOOP label1
3598    RET</font></pre>
3599
3600    <font face="Fixedsys">
3601    <table noshade="" border="1">
3602    <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
3603    <tr> <td colspan="6">unchanged</td> </tr>
3604    </tbody></table>
3605    </font>
3606
3607 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
3608
3609
3610                         <a name="LOOPE">&nbsp;</a>
3611 </td>
3612 </tr>
3613
3614
3615
3616
3617 <tr>
3618 <td>
3619 <font face="Fixedsys">
3620 LOOPE
3621 </font>
3622 </td>
3623 <td>
3624 <font face="Fixedsys">
3625         <nobr>label</nobr>
3626 </font>
3627 </td>
3628 <td>
3629
3630 Decrease CX, jump to label if CX not zero and Equal (ZF = 1). <br><br>Algorithm:
3631 <br><br>
3632 <font face="Fixedsys">
3633 <ul>
3634 <li>CX = CX - 1<br></li>
3635 <li>if (CX &lt;&gt; 0) and (ZF = 1) then
3636         <ul>
3637         <li>jump</li>
3638         </ul>
3639         else
3640         <ul>
3641         <li>no jump, continue</li>
3642         </ul>
3643 </li>
3644 </ul>
3645 </font>
3646 Example:<pre><font face="Fixedsys">; Loop until result fits into AL alone,
3647 ; or 5 times. The result will be over 255
3648 ; on third loop (100+100+100),
3649 ; so loop will exit.
3650
3651    include 'emu8086.inc'
3652
3653    ORG 100h
3654    MOV AX, 0
3655    MOV CX, 5
3656 label1:
3657    PUTC '*'
3658    ADD AX, 100
3659    CMP AH, 0
3660    LOOPE label1
3661    RET</font></pre>
3662
3663 <font face="Fixedsys">
3664 <table noshade="" border="1">
3665 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
3666 <tr> <td colspan="6">unchanged</td> </tr>
3667 </tbody></table>
3668 </font>
3669
3670 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
3671
3672
3673                         <a name="LOOPNE">&nbsp;</a>
3674 </td>
3675 </tr>
3676
3677
3678
3679
3680 <tr>
3681 <td>
3682 <font face="Fixedsys">
3683 LOOPNE
3684 </font>
3685 </td>
3686 <td>
3687 <font face="Fixedsys">
3688         <nobr>label</nobr>
3689 </font>
3690 </td>
3691 <td>
3692
3693 Decrease CX, jump to label if CX not zero and Not Equal (ZF = 0). <br><br>Algorithm:
3694 <br><br>
3695 <font face="Fixedsys">
3696 <ul>
3697 <li>CX = CX - 1<br></li>
3698 <li>if (CX &lt;&gt; 0) and (ZF = 0) then
3699         <ul>
3700         <li>jump</li>
3701         </ul>
3702         else
3703         <ul>
3704         <li>no jump, continue</li>
3705         </ul>
3706 </li>
3707 </ul>
3708 </font>
3709 Example:<pre><font face="Fixedsys">; Loop until '7' is found,
3710 ; or 5 times.
3711
3712    include 'emu8086.inc'
3713
3714    ORG 100h
3715    MOV SI, 0
3716    MOV CX, 5
3717 label1:
3718    PUTC '*'
3719    MOV AL, v1[SI]
3720    INC SI         ; next byte (SI=SI+1).
3721    CMP AL, 7
3722    LOOPNE label1
3723    RET
3724    v1 db 9, 8, 7, 6, 5</font></pre>
3725
3726 <font face="Fixedsys">
3727 <table noshade="" border="1">
3728 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
3729 <tr> <td colspan="6">unchanged</td> </tr>
3730 </tbody></table>
3731 </font>
3732
3733 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
3734
3735
3736                         <a name="LOOPNZ">&nbsp;</a>
3737 </td>
3738 </tr>
3739
3740
3741
3742
3743 <tr>
3744 <td>
3745 <font face="Fixedsys">
3746 LOOPNZ
3747 </font>
3748 </td>
3749 <td>
3750 <font face="Fixedsys">
3751         <nobr>label</nobr>
3752 </font>
3753 </td>
3754 <td>
3755
3756 Decrease CX, jump to label if CX not zero and ZF = 0. <br><br>Algorithm:
3757 <br><br>
3758 <font face="Fixedsys">
3759 <ul>
3760 <li>CX = CX - 1<br></li>
3761 <li>if (CX &lt;&gt; 0) and (ZF = 0) then
3762         <ul>
3763         <li>jump</li>
3764         </ul>
3765         else
3766         <ul>
3767         <li>no jump, continue</li>
3768         </ul>
3769 </li>
3770 </ul>
3771 </font>
3772 Example:<pre><font face="Fixedsys">; Loop until '7' is found,
3773 ; or 5 times.
3774
3775    include 'emu8086.inc'
3776
3777    ORG 100h
3778    MOV SI, 0
3779    MOV CX, 5
3780 label1:
3781    PUTC '*'
3782    MOV AL, v1[SI]
3783    INC SI         ; next byte (SI=SI+1).
3784    CMP AL, 7
3785    LOOPNZ label1
3786    RET
3787    v1 db 9, 8, 7, 6, 5</font></pre>
3788
3789 <font face="Fixedsys">
3790 <table noshade="" border="1">
3791 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
3792 <tr> <td colspan="6">unchanged</td> </tr>
3793 </tbody></table>
3794 </font>
3795
3796 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
3797
3798
3799                         <a name="LOOPZ">&nbsp;</a>
3800 </td>
3801 </tr>
3802
3803
3804
3805
3806 <tr>
3807 <td>
3808 <font face="Fixedsys">
3809 LOOPZ
3810 </font>
3811 </td>
3812 <td>
3813 <font face="Fixedsys">
3814         <nobr>label</nobr>
3815 </font>
3816
3817 </td>
3818 <td>
3819
3820 Decrease CX, jump to label if CX not zero and ZF = 1. <br><br>Algorithm:
3821 <br><br>
3822 <font face="Fixedsys">
3823 <ul>
3824 <li>CX = CX - 1<br></li>
3825 <li>if (CX &lt;&gt; 0) and (ZF = 1) then
3826         <ul>
3827         <li>jump</li>
3828         </ul>
3829         else
3830         <ul>
3831         <li>no jump, continue</li>
3832         </ul>
3833 </li>
3834 </ul>
3835 </font>
3836 Example:<pre><font face="Fixedsys">; Loop until result fits into AL alone,
3837 ; or 5 times. The result will be over 255
3838 ; on third loop (100+100+100),
3839 ; so loop will exit.
3840
3841    include 'emu8086.inc'
3842
3843    ORG 100h
3844    MOV AX, 0
3845    MOV CX, 5
3846 label1:
3847    PUTC '*'
3848    ADD AX, 100
3849    CMP AH, 0
3850    LOOPZ label1
3851    RET</font></pre>
3852
3853 <font face="Fixedsys">
3854 <table noshade="" border="1">
3855 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
3856 <tr> <td colspan="6">unchanged</td> </tr>
3857 </tbody></table>
3858 </font>
3859
3860 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
3861
3862
3863                         <a name="MOV">&nbsp;</a>
3864 </td>
3865 </tr>
3866
3867
3868
3869
3870 <tr>
3871 <td>
3872 <font face="Fixedsys">
3873 MOV
3874 </font>
3875 </td>
3876 <td>
3877 <font face="Fixedsys">
3878         <nobr>
3879         REG, memory<br>
3880         memory, REG<br>
3881         REG, REG<br>
3882         memory, immediate<br>
3883         REG, immediate<br><br>
3884
3885         SREG, memory<br>
3886         memory, SREG<br>
3887         REG, SREG<br>
3888         SREG, REG
3889         </nobr>
3890 </font>
3891 </td>
3892 <td>
3893
3894 Copy operand2 to operand1.<br><br>
3895 The MOV instruction <u>cannot</u>:
3896 <ul>
3897 <li>set the value of the CS and IP registers.</li>
3898 <li>copy value of one segment register to another segment register (should copy to general register first).</li>
3899 <li>copy immediate value to segment register (should copy to general register first).</li>
3900 </ul>
3901 <br>Algorithm:<br><br>
3902 <font face="Fixedsys">
3903 <blockquote>
3904 operand1 = operand2
3905 </blockquote>
3906 </font>
3907 Example:<pre><font face="Fixedsys">
3908 ORG 100h
3909 MOV AX, 0B800h    ; set AX = B800h (VGA memory).
3910 MOV DS, AX        ; copy value of AX to DS.
3911 MOV CL, 'A'       ; CL = 41h (ASCII code).
3912 MOV CH, 01011111b ; CL = color attribute.
3913 MOV BX, 15Eh      ; BX = position on screen.
3914 MOV [BX], CX      ; w.[0B800h:015Eh] = CX.
3915 RET               ; returns to operating system.
3916 </font></pre>
3917
3918 <font face="Fixedsys">
3919 <table noshade="" border="1">
3920 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
3921 <tr> <td colspan="6">unchanged</td> </tr>
3922 </tbody></table>
3923 </font>
3924
3925 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
3926
3927
3928                         <a name="MOVSB">&nbsp;</a>
3929 </td>
3930 </tr>
3931
3932
3933
3934
3935 <tr>
3936 <td>
3937 <font face="Fixedsys">
3938 MOVSB
3939 </font>
3940 </td>
3941 <td>No operands</td>
3942 <td>
3943
3944 Copy byte at DS:[SI] to ES:[DI].
3945 Update SI and DI.<br><br>Algorithm:
3946 <br><br>
3947 <font face="Fixedsys">
3948 <ul>
3949 <li>ES:[DI] = DS:[SI]<br></li>
3950 <li>if DF = 0 then
3951         <ul>
3952         <li>SI = SI + 1</li>
3953         <li>DI = DI + 1</li>
3954         </ul>
3955         else
3956         <ul>
3957         <li>SI = SI - 1</li>
3958         <li>DI = DI - 1</li>
3959         </ul>
3960 </li>
3961 </ul>
3962 </font>
3963 Example:<pre><font face="Fixedsys">
3964 ORG 100h
3965
3966 CLD
3967 LEA SI, a1
3968 LEA DI, a2
3969 MOV CX, 5
3970 REP MOVSB
3971
3972 RET
3973
3974 a1 DB 1,2,3,4,5
3975 a2 DB 5 DUP(0)</font></pre>
3976
3977 <font face="Fixedsys">
3978 <table noshade="" border="1">
3979 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
3980 <tr> <td colspan="6">unchanged</td> </tr>
3981 </tbody></table>
3982 </font>
3983
3984 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
3985
3986
3987                         <a name="MOVSW">&nbsp;</a>
3988 </td>
3989 </tr>
3990
3991
3992
3993
3994 <tr>
3995 <td>
3996 <font face="Fixedsys">
3997 MOVSW
3998 </font>
3999 </td>
4000 <td>No operands</td>
4001 <td>
4002
4003 Copy <b>word</b> at DS:[SI] to ES:[DI].
4004 Update SI and DI.<br><br>Algorithm:
4005 <br><br>
4006 <font face="Fixedsys">
4007 <ul>
4008 <li>ES:[DI] = DS:[SI]<br></li>
4009 <li>if DF = 0 then
4010         <ul>
4011         <li>SI = SI + 2</li>
4012         <li>DI = DI + 2</li>
4013         </ul>
4014         else
4015         <ul>
4016         <li>SI = SI - 2</li>
4017         <li>DI = DI - 2</li>
4018         </ul>
4019 </li>
4020 </ul>
4021 </font>
4022 Example:<pre><font face="Fixedsys">
4023 ORG 100h
4024
4025 CLD
4026 LEA SI, a1
4027 LEA DI, a2
4028 MOV CX, 5
4029 REP MOVSW
4030
4031 RET
4032
4033 a1 DW 1,2,3,4,5
4034 a2 DW 5 DUP(0)</font></pre>
4035
4036 <font face="Fixedsys">
4037 <table noshade="" border="1">
4038 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
4039 <tr> <td colspan="6">unchanged</td> </tr>
4040 </tbody></table>
4041 </font>
4042
4043 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4044
4045
4046                         <a name="MUL">&nbsp;</a>
4047 </td>
4048 </tr>
4049
4050
4051
4052
4053 <tr>
4054 <td>
4055 <font face="Fixedsys">
4056 MUL
4057 </font>
4058 </td>
4059 <td>
4060 <font face="Fixedsys">
4061         <nobr>
4062         REG<br>
4063         memory<br>
4064         </nobr>
4065 </font>
4066 </td>
4067 <td>
4068
4069 Unsigned multiply.
4070 <br><br>Algorithm:<br><br>
4071  <blockquote>
4072          when operand is a <b>byte</b>:<br>
4073          <font face="Fixedsys">AX = AL * operand</font>.
4074  </blockquote>
4075
4076  <blockquote>
4077         when operand is a <b>word</b>:<br>
4078         <font face="Fixedsys">(DX AX) = AX * operand</font>.
4079  </blockquote>
4080    Example:<pre><font face="Fixedsys">MOV AL, 200   ; AL = 0C8h
4081 MOV BL, 4
4082 MUL BL        ; AX = 0320h (800)
4083 RET</font></pre>
4084
4085 <font face="Fixedsys">
4086 <table noshade="" border="1">
4087 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
4088 <tr> <td>r</td> <td>?</td> <td>?</td> <td>r</td> <td>?</td> <td>?</td> </tr>
4089 </tbody></table>
4090 CF=OF=0 when high section of the result is zero.
4091 </font>
4092
4093 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4094
4095
4096                         <a name="NEG">&nbsp;</a>
4097 </td>
4098 </tr>
4099
4100
4101
4102
4103 <tr>
4104 <td>
4105 <font face="Fixedsys">
4106 NEG
4107 </font>
4108 </td>
4109 <td>
4110 <font face="Fixedsys">
4111         <nobr>
4112         REG<br>
4113         memory<br>
4114         </nobr>
4115 </font>
4116 </td>
4117 <td>
4118
4119 Negate. Makes operand negative (two's complement).
4120 <br><br>Algorithm:<br><br>
4121  <font face="Fixedsys">
4122  <ul>
4123  <li>Invert all bits of the operand</li>
4124  <li>Add 1 to inverted operand</li>
4125  </ul>
4126  </font>
4127     Example:<pre><font face="Fixedsys">MOV AL, 5   ; AL = 05h
4128 NEG AL      ; AL = 0FBh (-5)
4129 NEG AL      ; AL = 05h (5)
4130 RET</font></pre>
4131
4132 <font face="Fixedsys">
4133 <table noshade="" border="1">
4134 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
4135 <tr> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> </tr>
4136 </tbody></table>
4137 </font>
4138
4139 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4140
4141
4142                         <a name="NOP">&nbsp;</a>
4143 </td>
4144 </tr>
4145
4146
4147
4148
4149 <tr>
4150 <td>
4151 <font face="Fixedsys">
4152 NOP
4153 </font>
4154 </td>
4155 <td>No operands</td>
4156 <td>
4157
4158 No Operation.<br><br>Algorithm:
4159 <br><br>
4160 <font face="Fixedsys">
4161 </font><ul>
4162 <font face="Fixedsys"><li>Do nothing<br></li>
4163 </font></ul>
4164 <font face="Fixedsys"></font>
4165     Example:<pre><font face="Fixedsys">; do nothing, 3 times:
4166 NOP
4167 NOP
4168 NOP
4169 RET</font></pre>
4170
4171 <font face="Fixedsys">
4172 <table noshade="" border="1">
4173 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
4174 <tr> <td colspan="6">unchanged</td> </tr>
4175 </tbody></table>
4176 </font>
4177
4178 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4179
4180
4181                         <a name="NOT">&nbsp;</a>
4182 </td>
4183 </tr>
4184
4185
4186
4187
4188 <tr>
4189 <td>
4190 <font face="Fixedsys">
4191 NOT
4192 </font>
4193 </td>
4194 <td>
4195 <font face="Fixedsys">
4196         <nobr>
4197         REG<br>
4198         memory<br>
4199         </nobr>
4200 </font>
4201 </td>
4202 <td>
4203
4204 Invert each bit of the operand.<br><br>Algorithm:
4205 <br><br>
4206 <font face="Fixedsys">
4207 <ul>
4208 <li>if bit is 1 turn it to 0.<br></li>
4209 <li>if bit is 0 turn it to 1.<br></li>
4210 </ul>
4211 </font>
4212     Example:<pre><font face="Fixedsys">MOV AL, 00011011b
4213 NOT AL   ; AL = 11100100b
4214 RET</font></pre>
4215
4216 <font face="Fixedsys">
4217 <table noshade="" border="1">
4218 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
4219 <tr> <td colspan="6">unchanged</td> </tr>
4220 </tbody></table>
4221 </font>
4222
4223 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4224
4225
4226                         <a name="OR">&nbsp;</a>
4227 </td>
4228 </tr>
4229
4230
4231
4232 <tr>
4233 <td>
4234 <font face="Fixedsys">
4235 OR
4236 </font>
4237 </td>
4238 <td>
4239 <font face="Fixedsys">
4240         <nobr>
4241         REG, memory<br>
4242         memory, REG<br>
4243         REG, REG<br>
4244         memory, immediate<br>
4245         REG, immediate
4246         </nobr>
4247 </font>
4248 </td>
4249 <td>
4250
4251 Logical OR between all bits of two operands.
4252 Result is stored in first operand.<br><br>
4253 These rules apply:<br><br>
4254 <font face="Fixedsys">
4255 1 OR 1 = 1<br>
4256 1 OR 0 = 1<br>
4257 0 OR 1 = 1<br>
4258 0 OR 0 = 0<br>
4259 </font>
4260 <br><br>Example:<pre><font face="Fixedsys">MOV AL, 'A'       ; AL = 01000001b
4261 OR AL, 00100000b  ; AL = 01100001b  ('a')
4262 RET</font></pre>
4263
4264 <font face="Fixedsys">
4265 <table noshade="" border="1">
4266 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
4267 <tr> <td>0</td> <td>r</td> <td>r</td> <td>0</td> <td>r</td> <td>?</td> </tr>
4268 </tbody></table>
4269 </font>
4270
4271 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4272
4273
4274                         <a name="OUT">&nbsp;</a>
4275 </td>
4276 </tr>
4277
4278 <tr>
4279 <td>
4280 <font face="Fixedsys">
4281 OUT
4282 </font>
4283 </td>
4284 <td>
4285 <font face="Fixedsys">
4286         <nobr>
4287         im.byte, AL<br>
4288         im.byte, AX<br>
4289         DX, AL<br>
4290         DX, AX
4291         </nobr>
4292 </font>
4293 </td>
4294 <td>
4295
4296 Output from <b>AL</b> or <b>AX</b> to port.<br>
4297 First operand is a port number. If required to access
4298 port number over 255 - <b>DX</b> register should be used.
4299
4300 <br><br>Example:<pre><font face="Fixedsys">MOV AX, 0FFFh ; Turn on all
4301 OUT 4, AX     ; traffic lights.
4302
4303 MOV AL, 100b  ; Turn on the third
4304 OUT 7, AL     ; magnet of the stepper-motor.</font></pre>
4305
4306 <font face="Fixedsys">
4307 <table noshade="" border="1">
4308 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
4309 <tr> <td colspan="6">unchanged</td> </tr>
4310 </tbody></table>
4311 </font>
4312
4313 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4314
4315
4316                         <a name="POP">&nbsp;</a>
4317 </td>
4318 </tr>
4319
4320
4321 <tr>
4322 <td>
4323 <font face="Fixedsys">
4324 POP
4325 </font>
4326 </td>
4327 <td>
4328 <font face="Fixedsys">
4329         <nobr>
4330         REG<br>
4331         SREG<br>
4332         memory
4333         </nobr>
4334 </font>
4335 </td>
4336 <td>
4337
4338 Get 16 bit value from the stack.
4339 <br><br>Algorithm:<br><br>
4340  <font face="Fixedsys">
4341  <ul>
4342  <li>operand = SS:[SP] (top of the stack)</li>
4343  <li>SP = SP + 2</li>
4344  </ul>
4345  </font>
4346  <br>Example:<pre><font face="Fixedsys">MOV AX, 1234h
4347 PUSH AX
4348 POP  DX     ; DX = 1234h
4349 RET</font></pre>
4350
4351 <font face="Fixedsys">
4352 <table noshade="" border="1">
4353 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
4354 <tr> <td colspan="6">unchanged</td> </tr>
4355 </tbody></table>
4356 </font>
4357
4358 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4359
4360
4361                         <a name="POPA">&nbsp;</a>
4362 </td>
4363 </tr>
4364
4365
4366
4367
4368 <tr>
4369 <td>
4370 <font face="Fixedsys">
4371 POPA
4372 </font>
4373 </td>
4374 <td>No operands</td>
4375 <td>
4376
4377 Pop all general purpose registers DI, SI, BP, SP, BX, DX, CX, AX from the stack.<br>
4378 SP value is ignored, it is Popped but not set to SP register).<br><br>
4379 Note: this instruction works only on <b>80186</b> CPU and later!
4380 <br><br>Algorithm:<br><br>
4381  <font face="Fixedsys">
4382  <ul>
4383  <li>POP DI</li>
4384  <li>POP SI</li>
4385  <li>POP BP</li>
4386  <li>POP xx (SP value ignored)</li>
4387  <li>POP BX</li>
4388  <li>POP DX</li>
4389  <li>POP CX</li>
4390  <li>POP AX</li>
4391  </ul>
4392  </font>
4393
4394  <font face="Fixedsys">
4395  <table noshade="" border="1">
4396  <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
4397  <tr> <td colspan="6">unchanged</td> </tr>
4398  </tbody></table>
4399  </font>
4400
4401 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4402
4403
4404                         <a name="POPF">&nbsp;</a>
4405 </td>
4406 </tr>
4407
4408
4409
4410
4411 <tr>
4412 <td>
4413 <font face="Fixedsys">
4414 POPF
4415 </font>
4416 </td>
4417 <td>No operands</td>
4418 <td>
4419
4420 Get flags register from the stack.
4421 <br><br>Algorithm:<br><br>
4422  <font face="Fixedsys">
4423  <ul>
4424  <li>flags = SS:[SP] (top of the stack)</li>
4425  <li>SP = SP + 2</li>
4426  </ul>
4427  </font>
4428
4429  <font face="Fixedsys">
4430  <table noshade="" border="1">
4431  <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
4432  <tr> <td colspan="6"><center>popped</center></td> </tr>
4433  </tbody></table>
4434  </font>
4435
4436 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4437
4438
4439                         <a name="PUSH">&nbsp;</a>
4440 </td>
4441 </tr>
4442
4443
4444
4445
4446 <tr>
4447 <td>
4448 <font face="Fixedsys">
4449 PUSH
4450 </font>
4451 </td>
4452 <td>
4453 <font face="Fixedsys">
4454         <nobr>
4455         REG<br>
4456         SREG<br>
4457         memory<br>
4458         immediate
4459         </nobr>
4460 </font>
4461 </td>
4462 <td>
4463
4464 Store 16 bit value in the stack.<br><br>
4465
4466 Note: <b>PUSH immediate</b> works only on 80186 CPU and later!
4467 <br><br>Algorithm:<br><br>
4468  <font face="Fixedsys">
4469  <ul>
4470  <li>SP = SP - 2</li>
4471  <li>SS:[SP] (top of the stack) = operand</li>
4472  </ul>
4473  </font>
4474 <br>Example:<pre><font face="Fixedsys">MOV AX, 1234h
4475 PUSH AX
4476 POP  DX     ; DX = 1234h
4477 RET</font></pre>
4478
4479 <font face="Fixedsys">
4480 <table noshade="" border="1">
4481 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
4482 <tr> <td colspan="6">unchanged</td> </tr>
4483 </tbody></table>
4484 </font>
4485
4486 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4487
4488
4489                         <a name="PUSHA">&nbsp;</a>
4490 </td>
4491 </tr>
4492
4493
4494
4495
4496 <tr>
4497 <td>
4498 <font face="Fixedsys">
4499 PUSHA
4500 </font>
4501 </td>
4502 <td>No operands</td>
4503 <td>
4504
4505 Push all general purpose registers AX, CX, DX, BX, SP, BP, SI, DI in the stack.<br>
4506 Original value of SP register (before PUSHA) is used.<br><br>
4507 Note: this instruction works only on <b>80186</b> CPU and later!
4508 <br><br>Algorithm:<br><br>
4509  <font face="Fixedsys">
4510  <ul>
4511         <li>PUSH AX</li>
4512         <li>PUSH CX</li>
4513         <li>PUSH DX</li>
4514         <li>PUSH BX</li>
4515         <li>PUSH SP</li>
4516         <li>PUSH BP</li>
4517         <li>PUSH SI</li>
4518         <li>PUSH DI</li>
4519  </ul>
4520  </font>
4521
4522  <font face="Fixedsys">
4523  <table noshade="" border="1">
4524  <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
4525  <tr> <td colspan="6">unchanged</td> </tr>
4526  </tbody></table>
4527  </font>
4528
4529 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4530
4531
4532                         <a name="PUSHF">&nbsp;</a>
4533 </td>
4534 </tr>
4535
4536
4537
4538
4539 <tr>
4540 <td>
4541 <font face="Fixedsys">
4542 PUSHF
4543 </font>
4544 </td>
4545 <td>No operands</td>
4546 <td>
4547
4548 Store flags register in the stack.
4549 <br><br>Algorithm:<br><br>
4550  <font face="Fixedsys">
4551  </font><ul>
4552 <font face="Fixedsys"> <li>SP = SP - 2</li>
4553  <li>SS:[SP] (top of the stack) = flags</li>
4554  </font></ul>
4555 <font face="Fixedsys"> </font>
4556
4557  <font face="Fixedsys">
4558  <table noshade="" border="1">
4559  <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
4560  <tr> <td colspan="6">unchanged</td> </tr>
4561  </tbody></table>
4562  </font>
4563
4564 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4565
4566
4567                         <a name="RCL">&nbsp;</a>
4568 </td>
4569 </tr>
4570
4571
4572
4573
4574 <tr>
4575 <td>
4576 <font face="Fixedsys">
4577 RCL
4578 </font>
4579 </td>
4580 <td>
4581 <font face="Fixedsys">
4582         <nobr>memory, immediate</nobr><br>
4583         <nobr>REG, immediate</nobr><br><br>
4584         <nobr>memory, CL</nobr><br>
4585         <nobr>REG, CL</nobr>
4586 </font>
4587 </td>
4588 <td>
4589
4590 Rotate operand1 left through Carry Flag. The number of rotates is set by operand2.
4591 <br>
4592 When <b>immediate</b> is greater then 1, assembler generates several
4593 <b>RCL xx, 1</b> instructions because 8086 has machine code only for this
4594 instruction (the same principle works for all other shift/rotate instructions).
4595
4596 <br><br>Algorithm:<br><br>
4597 <font face="Fixedsys">
4598 <ul>
4599         shift all bits left, the bit that goes off is set to
4600         CF and previous value of CF is inserted to the right-most position.
4601 </ul>
4602 </font>
4603 <br>Example:<pre><font face="Fixedsys">STC               ; set carry (CF=1).
4604 MOV AL, 1Ch       ; AL = 00011100b
4605 RCL AL, 1         ; AL = 00111001b,  CF=0.
4606 RET</font></pre>
4607
4608 <font face="Fixedsys">
4609 <table noshade="" border="1">
4610 <tbody><tr> <td>C</td> <td>O</td> </tr>
4611 <tr> <td>r</td> <td>r</td> </tr>
4612 </tbody></table>
4613 OF=0 if first operand keeps original sign.
4614 </font>
4615
4616 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4617
4618
4619                         <a name="RCR">&nbsp;</a>
4620 </td>
4621 </tr>
4622
4623
4624
4625
4626 <tr>
4627 <td>
4628 <font face="Fixedsys">
4629 RCR
4630 </font>
4631 </td>
4632 <td>
4633 <font face="Fixedsys">
4634         <nobr>memory, immediate</nobr><br>
4635         <nobr>REG, immediate</nobr><br><br>
4636         <nobr>memory, CL</nobr><br>
4637         <nobr>REG, CL</nobr>
4638 </font>
4639 </td>
4640 <td>
4641
4642 Rotate operand1 right through Carry Flag. The number of rotates is set by operand2.
4643
4644 <br><br>Algorithm:<br><br>
4645 <font face="Fixedsys">
4646 <ul>
4647         shift all bits right, the bit that goes off is set to
4648         CF and previous value of CF is inserted to the left-most position.
4649 </ul>
4650 </font>
4651 <br>Example:<pre><font face="Fixedsys">STC               ; set carry (CF=1).
4652 MOV AL, 1Ch       ; AL = 00011100b
4653 RCR AL, 1         ; AL = 10001110b,  CF=0.
4654 RET</font></pre>
4655
4656 <font face="Fixedsys">
4657 <table noshade="" border="1">
4658 <tbody><tr> <td>C</td> <td>O</td> </tr>
4659 <tr> <td>r</td> <td>r</td> </tr>
4660 </tbody></table>
4661 OF=0 if first operand keeps original sign.
4662 </font>
4663
4664 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4665
4666
4667                         <a name="REP">&nbsp;</a>
4668 </td>
4669 </tr>
4670
4671
4672
4673
4674 <tr>
4675 <td>
4676 <font face="Fixedsys">
4677 REP
4678 </font>
4679 </td>
4680 <td>
4681 <font face="Fixedsys">
4682         <nobr>chain instruction</nobr><br>
4683 </font>
4684 </td>
4685 <td>
4686
4687 Repeat following MOVSB, MOVSW, LODSB, LODSW, STOSB, STOSW instructions
4688 CX times.
4689 <br><br>Algorithm:<br><br>
4690 <font face="Fixedsys">
4691 check_cx:<br><br>
4692 if CX &lt;&gt; 0 then
4693 <ul>
4694         <li>do following <u>chain instruction</u></li>
4695         <li>CX = CX - 1</li>
4696         <li>go back to check_cx</li>
4697 </ul>
4698 else
4699 <ul>
4700         <li>exit from REP cycle</li>
4701 </ul>
4702 </font>
4703
4704 <font face="Fixedsys">
4705 <table noshade="" border="1">
4706 <tbody><tr> <td>Z</td> </tr>
4707 <tr> <td>r</td>  </tr>
4708 </tbody></table>
4709 </font>
4710
4711 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4712
4713
4714                         <a name="REPE">&nbsp;</a>
4715 </td>
4716 </tr>
4717
4718
4719
4720
4721
4722 <tr>
4723 <td>
4724 <font face="Fixedsys">
4725 REPE
4726 </font>
4727 </td>
4728 <td>
4729 <font face="Fixedsys">
4730         <nobr>chain instruction</nobr><br>
4731 </font>
4732 </td>
4733 <td>
4734
4735 Repeat following CMPSB, CMPSW, SCASB, SCASW instructions
4736 while ZF = 1 (result is Equal), maximum CX times.
4737 <br><br>Algorithm:<br><br>
4738 <font face="Fixedsys">
4739 check_cx:<br><br>
4740 if CX &lt;&gt; 0 then
4741 <ul>
4742         <li>do following <u>chain instruction</u></li>
4743         <li>CX = CX - 1</li>
4744         <li>if ZF = 1 then:
4745                 <ul>
4746                 <li>go back to check_cx</li>
4747                 </ul>
4748         else
4749                 <ul>
4750                 <li>exit from REPE cycle</li>
4751                 </ul>
4752         </li>
4753 </ul>
4754 else
4755 <ul>
4756         <li>exit from REPE cycle</li>
4757 </ul>
4758 </font>
4759 Example:<br>
4760 see <b>cmpsb.asm</b> in c:\emu8086\examples\.
4761
4762 <br><br>
4763
4764 <font face="Fixedsys">
4765 <table noshade="" border="1">
4766 <tbody><tr> <td>Z</td> </tr>
4767 <tr> <td>r</td>  </tr>
4768 </tbody></table>
4769 </font>
4770
4771 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4772
4773
4774                         <a name="REPNE">&nbsp;</a>
4775 </td>
4776 </tr>
4777
4778
4779
4780
4781
4782 <tr>
4783 <td>
4784 <font face="Fixedsys">
4785 REPNE
4786 </font>
4787 </td>
4788 <td>
4789 <font face="Fixedsys">
4790         <nobr>chain instruction</nobr><br>
4791 </font>
4792 </td>
4793 <td>
4794
4795 Repeat following CMPSB, CMPSW, SCASB, SCASW instructions
4796 while ZF = 0 (result is Not Equal), maximum CX times.
4797 <br><br>Algorithm:<br><br>
4798 <font face="Fixedsys">
4799 check_cx:<br><br>
4800 if CX &lt;&gt; 0 then
4801 <ul>
4802         <li>do following <u>chain instruction</u></li>
4803         <li>CX = CX - 1</li>
4804         <li>if ZF = 0 then:
4805                 <ul>
4806                 <li>go back to check_cx</li>
4807                 </ul>
4808         else
4809                 <ul>
4810                 <li>exit from REPNE cycle</li>
4811                 </ul>
4812         </li>
4813 </ul>
4814 else
4815 <ul>
4816         <li>exit from REPNE cycle</li>
4817 </ul>
4818 </font>
4819
4820 <font face="Fixedsys">
4821 <table noshade="" border="1">
4822 <tbody><tr> <td>Z</td> </tr>
4823 <tr> <td>r</td>  </tr>
4824 </tbody></table>
4825 </font>
4826
4827 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4828
4829
4830                         <a name="REPNZ">&nbsp;</a>
4831 </td>
4832 </tr>
4833
4834
4835
4836
4837
4838 <tr>
4839 <td>
4840 <font face="Fixedsys">
4841 REPNZ
4842 </font>
4843 </td>
4844 <td>
4845 <font face="Fixedsys">
4846         <nobr>chain instruction</nobr><br>
4847 </font>
4848 </td>
4849 <td>
4850
4851 Repeat following CMPSB, CMPSW, SCASB, SCASW instructions
4852 while ZF = 0 (result is Not Zero), maximum CX times.
4853 <br><br>Algorithm:<br><br>
4854 <font face="Fixedsys">
4855 check_cx:<br><br>
4856 if CX &lt;&gt; 0 then
4857 </font><ul>
4858 <font face="Fixedsys">  <li>do following <u>chain instruction</u></li>
4859         <li>CX = CX - 1</li>
4860         <li>if ZF = 0 then:
4861                 <ul>
4862                 <li>go back to check_cx</li>
4863                 </ul>
4864         else
4865                 <ul>
4866                 <li>exit from REPNZ cycle</li>
4867                 </ul>
4868         </li>
4869 </font></ul>
4870 <font face="Fixedsys">else
4871 </font><ul>
4872 <font face="Fixedsys">  <li>exit from REPNZ cycle</li>
4873 </font></ul>
4874 <font face="Fixedsys"></font>
4875
4876 <font face="Fixedsys">
4877 <table noshade="" border="1">
4878 <tbody><tr> <td>Z</td> </tr>
4879 <tr> <td>r</td>  </tr>
4880 </tbody></table>
4881 </font>
4882
4883 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4884
4885
4886                         <a name="REPZ">&nbsp;</a>
4887 </td>
4888 </tr>
4889
4890
4891
4892
4893
4894 <tr>
4895 <td>
4896 <font face="Fixedsys">
4897 REPZ
4898 </font>
4899 </td>
4900 <td>
4901 <font face="Fixedsys">
4902         <nobr>chain instruction</nobr><br>
4903 </font>
4904 </td>
4905 <td>
4906
4907 Repeat following CMPSB, CMPSW, SCASB, SCASW instructions
4908 while ZF = 1 (result is Zero), maximum CX times.
4909 <br><br>Algorithm:<br><br>
4910 <font face="Fixedsys">
4911 check_cx:<br><br>
4912 if CX &lt;&gt; 0 then
4913 <ul>
4914         <li>do following <u>chain instruction</u></li>
4915         <li>CX = CX - 1</li>
4916         <li>if ZF = 1 then:
4917                 <ul>
4918                 <li>go back to check_cx</li>
4919                 </ul>
4920         else
4921                 <ul>
4922                 <li>exit from REPZ cycle</li>
4923                 </ul>
4924         </li>
4925 </ul>
4926 else
4927 <ul>
4928         <li>exit from REPZ cycle</li>
4929 </ul>
4930 </font>
4931
4932 <font face="Fixedsys">
4933 <table noshade="" border="1">
4934 <tbody><tr> <td>Z</td> </tr>
4935 <tr> <td>r</td>  </tr>
4936 </tbody></table>
4937 </font>
4938
4939 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4940
4941
4942                         <a name="RET">&nbsp;</a>
4943 </td>
4944 </tr>
4945
4946
4947
4948
4949 <tr>
4950 <td>
4951 <font face="Fixedsys">
4952 RET
4953 </font>
4954 </td>
4955 <td>No operands<br>
4956 or even immediate</td>
4957 <td>
4958
4959 Return from near procedure.
4960 <br><br>Algorithm:<br><br>
4961 <font face="Fixedsys">
4962 </font><ul>
4963 <font face="Fixedsys">  <li>
4964                 Pop from stack:
4965                 <ul>
4966                 <li>IP</li>
4967                 </ul>
4968         </li>
4969         <li>
4970         if <u>immediate</u> operand is present:
4971         <nobr>SP = SP + operand</nobr>
4972         </li>
4973 </font></ul>
4974 <font face="Fixedsys"></font>
4975 Example:<pre><font face="Fixedsys">
4976 ORG 100h  ; for COM file.
4977
4978 CALL p1
4979
4980 ADD AX, 1
4981
4982 RET         ; return to OS.
4983
4984 p1 PROC     ; procedure declaration.
4985     MOV AX, 1234h
4986     RET     ; return to caller.
4987 p1 ENDP</font></pre>
4988
4989 <font face="Fixedsys">
4990 <table noshade="" border="1">
4991 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
4992 <tr> <td colspan="6">unchanged</td> </tr>
4993 </tbody></table>
4994 </font>
4995
4996 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
4997
4998
4999                         <a name="RETF">&nbsp;</a>
5000 </td>
5001 </tr>
5002
5003
5004
5005
5006 <tr>
5007 <td>
5008 <font face="Fixedsys">
5009 RETF
5010 </font>
5011 </td>
5012 <td>No operands<br>
5013 or even immediate</td>
5014 <td>
5015
5016 Return from Far procedure.
5017 <br><br>Algorithm:<br><br>
5018 <font face="Fixedsys">
5019 <ul>
5020         <li>
5021                 Pop from stack:
5022                 <ul>
5023                 <li>IP</li>
5024                 <li>CS</li>
5025                 </ul>
5026         </li>
5027         <li>
5028         if <u>immediate</u> operand is present:
5029         <nobr>SP = SP + operand</nobr>
5030         </li>
5031 </ul>
5032 </font>
5033
5034 <font face="Fixedsys">
5035 <table noshade="" border="1">
5036 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
5037 <tr> <td colspan="6">unchanged</td> </tr>
5038 </tbody></table>
5039 </font>
5040
5041 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5042
5043
5044                         <a name="ROL">&nbsp;</a>
5045 </td>
5046 </tr>
5047
5048
5049
5050
5051 <tr>
5052 <td>
5053 <font face="Fixedsys">
5054 ROL
5055 </font>
5056 </td>
5057 <td>
5058 <font face="Fixedsys">
5059         <nobr>memory, immediate</nobr><br>
5060         <nobr>REG, immediate</nobr><br><br>
5061         <nobr>memory, CL</nobr><br>
5062         <nobr>REG, CL</nobr>
5063 </font>
5064 </td>
5065 <td>
5066
5067 Rotate operand1 left. The number of rotates is set by operand2.
5068
5069 <br><br>Algorithm:<br><br>
5070 <font face="Fixedsys">
5071 <ul>
5072         shift all bits left, the bit that goes off is set to
5073         CF and the same bit is inserted to the right-most position.
5074 </ul>
5075 </font>
5076 Example:<pre><font face="Fixedsys">MOV AL, 1Ch       ; AL = 00011100b
5077 ROL AL, 1         ; AL = 00111000b,  CF=0.
5078 RET</font></pre>
5079
5080 <font face="Fixedsys">
5081 <table noshade="" border="1">
5082 <tbody><tr> <td>C</td> <td>O</td> </tr>
5083 <tr> <td>r</td> <td>r</td> </tr>
5084 </tbody></table>
5085 OF=0 if first operand keeps original sign.
5086 </font>
5087
5088 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5089
5090
5091                         <a name="ROR">&nbsp;</a>
5092 </td>
5093 </tr>
5094
5095
5096
5097
5098 <tr>
5099 <td>
5100 <font face="Fixedsys">
5101 ROR
5102 </font>
5103 </td>
5104 <td>
5105 <font face="Fixedsys">
5106         <nobr>memory, immediate</nobr><br>
5107         <nobr>REG, immediate</nobr><br><br>
5108         <nobr>memory, CL</nobr><br>
5109         <nobr>REG, CL</nobr>
5110 </font>
5111 </td>
5112 <td>
5113
5114 Rotate operand1 right. The number of rotates is set by operand2.
5115
5116 <br><br>Algorithm:<br><br>
5117 <font face="Fixedsys">
5118 <ul>
5119         shift all bits right, the bit that goes off is set to
5120         CF and the same bit is inserted to the left-most position.
5121 </ul>
5122 </font>
5123 Example:<pre><font face="Fixedsys">MOV AL, 1Ch       ; AL = 00011100b
5124 ROR AL, 1         ; AL = 00001110b,  CF=0.
5125 RET</font></pre>
5126
5127 <font face="Fixedsys">
5128 <table noshade="" border="1">
5129 <tbody><tr> <td>C</td> <td>O</td> </tr>
5130 <tr> <td>r</td> <td>r</td> </tr>
5131 </tbody></table>
5132 OF=0 if first operand keeps original sign.
5133 </font>
5134
5135 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5136
5137
5138                         <a name="SAHF">&nbsp;</a>
5139 </td>
5140 </tr>
5141
5142
5143
5144
5145 <tr>
5146 <td>
5147 <font face="Fixedsys">
5148 SAHF
5149 </font>
5150 </td>
5151 <td>No operands</td>
5152 <td>
5153
5154 Store AH register into low 8 bits of Flags register.
5155 <br><br>Algorithm:<br><br>
5156 <font face="Fixedsys">
5157 <ul>
5158         flags register = AH<br>
5159 </ul>
5160 <pre><font face="Fixedsys">
5161 AH bit:   7    6   5    4   3    2   1    0
5162         [SF] [ZF] [0] [AF] [0] [PF] [1] [CF]</font>
5163 </pre>
5164 bits 1, 3, 5 are reserved.
5165 </font>
5166
5167 <br><br>
5168
5169
5170 <font face="Fixedsys">
5171 <table noshade="" border="1">
5172 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
5173 <tr> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> </tr>
5174 </tbody></table>
5175 </font>
5176
5177
5178 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5179
5180
5181                         <a name="SAL">&nbsp;</a>
5182 </td>
5183 </tr>
5184
5185
5186
5187
5188
5189 <tr>
5190 <td>
5191 <font face="Fixedsys">
5192 SAL
5193 </font>
5194 </td>
5195 <td>
5196 <font face="Fixedsys">
5197         <nobr>memory, immediate</nobr><br>
5198         <nobr>REG, immediate</nobr><br><br>
5199         <nobr>memory, CL</nobr><br>
5200         <nobr>REG, CL</nobr>
5201 </font>
5202 </td>
5203 <td>
5204
5205 Shift Arithmetic operand1 Left. The number of shifts is set by operand2.
5206
5207 <br><br>Algorithm:<br><br>
5208 <font face="Fixedsys">
5209 </font><ul>
5210 <font face="Fixedsys">  <li>Shift all bits left, the bit that goes off is set to CF.</li>
5211         <li>Zero bit is inserted to the right-most position.</li>
5212 </font></ul>
5213 <font face="Fixedsys"></font>
5214 Example:<pre><font face="Fixedsys">MOV AL, 0E0h      ; AL = 11100000b
5215 SAL AL, 1         ; AL = 11000000b,  CF=1.
5216 RET</font></pre>
5217
5218 <font face="Fixedsys">
5219 <table noshade="" border="1">
5220 <tbody><tr> <td>C</td> <td>O</td> </tr>
5221 <tr> <td>r</td> <td>r</td> </tr>
5222 </tbody></table>
5223 OF=0 if first operand keeps original sign.
5224 </font>
5225
5226 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5227
5228
5229                         <a name="SAR">&nbsp;</a>
5230 </td>
5231 </tr>
5232
5233
5234
5235
5236
5237 <tr>
5238 <td>
5239 <font face="Fixedsys">
5240 SAR
5241 </font>
5242 </td>
5243 <td>
5244 <font face="Fixedsys">
5245         <nobr>memory, immediate</nobr><br>
5246         <nobr>REG, immediate</nobr><br><br>
5247         <nobr>memory, CL</nobr><br>
5248         <nobr>REG, CL</nobr>
5249 </font>
5250 </td>
5251 <td>
5252
5253 Shift Arithmetic operand1 Right. The number of shifts is set by operand2.
5254
5255 <br><br>Algorithm:<br><br>
5256 <font face="Fixedsys">
5257 <ul>
5258         <li>Shift all bits right, the bit that goes off is set to CF.</li>
5259         <li>The sign bit that is inserted to the left-most position has
5260             the same value as before shift.</li>
5261 </ul>
5262 </font>
5263 Example:<pre><font face="Fixedsys">MOV AL, 0E0h      ; AL = 11100000b
5264 SAR AL, 1         ; AL = 11110000b,  CF=0.
5265
5266 MOV BL, 4Ch       ; BL = 01001100b
5267 SAR BL, 1         ; BL = 00100110b,  CF=0.
5268
5269 RET</font></pre>
5270
5271 <font face="Fixedsys">
5272 <table noshade="" border="1">
5273 <tbody><tr> <td>C</td> <td>O</td> </tr>
5274 <tr> <td>r</td> <td>r</td> </tr>
5275 </tbody></table>
5276 OF=0 if first operand keeps original sign.
5277 </font>
5278
5279 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5280
5281
5282                         <a name="SBB">&nbsp;</a>
5283 </td>
5284 </tr>
5285
5286
5287
5288
5289 <tr>
5290 <td>
5291 <font face="Fixedsys">
5292 SBB
5293 </font>
5294 </td>
5295 <td>
5296 <font face="Fixedsys">
5297         <nobr>
5298         REG, memory<br>
5299         memory, REG<br>
5300         REG, REG<br>
5301         memory, immediate<br>
5302         REG, immediate
5303         </nobr>
5304 </font>
5305 </td>
5306 <td>
5307
5308 Subtract with Borrow.
5309 <br><br>Algorithm:<br><br>
5310 <font face="Fixedsys">
5311 operand1 = operand1 - operand2 - CF
5312 </font>
5313 <br><br>
5314 Example:<pre><font face="Fixedsys">STC
5315 MOV AL, 5
5316 SBB AL, 3    ; AL = 5 - 3 - 1 = 1
5317
5318 RET</font></pre>
5319
5320 <font face="Fixedsys">
5321 <table noshade="" border="1">
5322 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
5323 <tr> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> </tr>
5324 </tbody></table>
5325 </font>
5326
5327 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5328
5329
5330                         <a name="SCASB">&nbsp;</a>
5331 </td>
5332 </tr>
5333
5334
5335
5336
5337
5338 <tr>
5339 <td>
5340 <font face="Fixedsys">
5341 SCASB
5342 </font>
5343 </td>
5344 <td>No operands</td>
5345 <td>
5346
5347 Compare bytes: <nobr>AL from ES:[DI].</nobr> <br><br>Algorithm:
5348 <br><br>
5349 <font face="Fixedsys">
5350 </font><ul>
5351 <font face="Fixedsys"><li>ES:[DI] - AL<br></li>
5352 <li>set flags according to result:<br> OF, SF, ZF, AF, PF, CF<br></li>
5353 <li>if DF = 0 then
5354         <ul>
5355         <li>DI = DI + 1</li>
5356         </ul>
5357         else
5358         <ul>
5359         <li>DI = DI - 1</li>
5360         </ul>
5361 </li>
5362 </font></ul>
5363 <font face="Fixedsys"></font>
5364
5365 <font face="Fixedsys">
5366 <table noshade="" border="1">
5367 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
5368 <tr> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> </tr>
5369 </tbody></table>
5370 </font>
5371
5372 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5373
5374
5375                         <a name="SCASW">&nbsp;</a>
5376 </td>
5377 </tr>
5378
5379
5380
5381
5382 <tr>
5383 <td>
5384 <font face="Fixedsys">
5385 SCASW
5386 </font>
5387 </td>
5388 <td>No operands</td>
5389 <td>
5390
5391 Compare words: <nobr>AX from ES:[DI].</nobr> <br><br>Algorithm:
5392 <br><br>
5393 <font face="Fixedsys">
5394 <ul>
5395 <li>ES:[DI] - AX<br></li>
5396 <li>set flags according to result:<br> OF, SF, ZF, AF, PF, CF<br></li>
5397 <li>if DF = 0 then
5398         <ul>
5399         <li>DI = DI + 2</li>
5400         </ul>
5401         else
5402         <ul>
5403         <li>DI = DI - 2</li>
5404         </ul>
5405 </li>
5406 </ul>
5407 </font>
5408
5409 <font face="Fixedsys">
5410 <table noshade="" border="1">
5411 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
5412 <tr> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> </tr>
5413 </tbody></table>
5414 </font>
5415
5416 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5417
5418
5419                         <a name="SHL">&nbsp;</a>
5420 </td>
5421 </tr>
5422
5423
5424
5425
5426
5427 <tr>
5428 <td>
5429 <font face="Fixedsys">
5430 SHL
5431 </font>
5432 </td>
5433 <td>
5434 <font face="Fixedsys">
5435         <nobr>memory, immediate</nobr><br>
5436         <nobr>REG, immediate</nobr><br><br>
5437         <nobr>memory, CL</nobr><br>
5438         <nobr>REG, CL</nobr>
5439 </font>
5440 </td>
5441 <td>
5442
5443 Shift operand1 Left. The number of shifts is set by operand2.
5444
5445 <br><br>Algorithm:<br><br>
5446 <font face="Fixedsys">
5447 <ul>
5448         <li>Shift all bits left, the bit that goes off is set to CF.</li>
5449         <li>Zero bit is inserted to the right-most position.</li>
5450 </ul>
5451 </font>
5452 Example:<pre><font face="Fixedsys">MOV AL, 11100000b
5453 SHL AL, 1         ; AL = 11000000b,  CF=1.
5454
5455 RET</font></pre>
5456
5457 <font face="Fixedsys">
5458 <table noshade="" border="1">
5459 <tbody><tr> <td>C</td> <td>O</td> </tr>
5460 <tr> <td>r</td> <td>r</td> </tr>
5461 </tbody></table>
5462 OF=0 if first operand keeps original sign.
5463 </font>
5464
5465 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5466
5467
5468                         <a name="SHR">&nbsp;</a>
5469 </td>
5470 </tr>
5471
5472
5473
5474
5475
5476 <tr>
5477 <td>
5478 <font face="Fixedsys">
5479 SHR
5480 </font>
5481 </td>
5482 <td>
5483 <font face="Fixedsys">
5484         <nobr>memory, immediate</nobr><br>
5485         <nobr>REG, immediate</nobr><br><br>
5486         <nobr>memory, CL</nobr><br>
5487         <nobr>REG, CL</nobr>
5488 </font>
5489 </td>
5490 <td>
5491
5492 Shift operand1 Right. The number of shifts is set by operand2.
5493
5494 <br><br>Algorithm:<br><br>
5495 <font face="Fixedsys">
5496 <ul>
5497         <li>Shift all bits right, the bit that goes off is set to CF.</li>
5498         <li>Zero bit is inserted to the left-most position.</li>
5499 </ul>
5500 </font>
5501 Example:<pre><font face="Fixedsys">MOV AL, 00000111b
5502 SHR AL, 1         ; AL = 00000011b,  CF=1.
5503
5504 RET</font></pre>
5505
5506 <font face="Fixedsys">
5507 <table noshade="" border="1">
5508 <tbody><tr> <td>C</td> <td>O</td> </tr>
5509 <tr> <td>r</td> <td>r</td> </tr>
5510 </tbody></table>
5511 OF=0 if first operand keeps original sign.
5512 </font>
5513
5514 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5515
5516
5517                         <a name="STC">&nbsp;</a>
5518 </td>
5519 </tr>
5520
5521
5522
5523
5524 <tr>
5525 <td>
5526 <font face="Fixedsys">
5527 STC
5528 </font>
5529 </td>
5530 <td>No operands</td>
5531 <td>
5532
5533 Set Carry flag. <br><br>Algorithm:
5534 <br><br>
5535 <font face="Fixedsys">
5536 CF = 1
5537 </font>
5538
5539 <br><br>
5540
5541 <font face="Fixedsys">
5542 <table noshade="" border="1">
5543 <tbody><tr> <td>C</td> </tr>
5544 <tr> <td>1</td> </tr>
5545 </tbody></table>
5546 </font>
5547
5548 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5549
5550
5551                         <a name="STD">&nbsp;</a>
5552 </td>
5553 </tr>
5554
5555
5556
5557
5558 <tr>
5559 <td>
5560 <font face="Fixedsys">
5561 STD
5562 </font>
5563 </td>
5564 <td>No operands</td>
5565 <td>
5566
5567 Set Direction flag. SI and DI will be decremented by chain
5568 instructions: CMPSB, CMPSW, LODSB, LODSW, MOVSB, MOVSW, STOSB, STOSW. <br><br>Algorithm:
5569 <br><br>
5570 <font face="Fixedsys">
5571 DF = 1
5572 </font>
5573 <br><br>
5574
5575 <font face="Fixedsys">
5576 <table noshade="" border="1">
5577 <tbody><tr> <td>D</td> </tr>
5578 <tr> <td>1</td> </tr>
5579 </tbody></table>
5580 </font>
5581
5582 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5583
5584
5585                         <a name="STI">&nbsp;</a>
5586 </td>
5587 </tr>
5588
5589
5590
5591
5592
5593
5594 <tr>
5595 <td>
5596 <font face="Fixedsys">
5597 STI
5598 </font>
5599 </td>
5600 <td>No operands</td>
5601 <td>
5602
5603 Set Interrupt enable flag. This enables hardware interrupts. <br><br>Algorithm:
5604 <br><br>
5605 <font face="Fixedsys">
5606 IF = 1
5607 </font>
5608 <br><br>
5609
5610 <font face="Fixedsys">
5611 <table noshade="" border="1">
5612 <tbody><tr> <td>I</td> </tr>
5613 <tr> <td>1</td> </tr>
5614 </tbody></table>
5615 </font>
5616
5617 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5618
5619
5620                         <a name="STOSB">&nbsp;</a>
5621 </td>
5622 </tr>
5623
5624
5625
5626
5627 <tr>
5628 <td>
5629 <font face="Fixedsys">
5630 STOSB
5631 </font>
5632 </td>
5633 <td>No operands</td>
5634 <td>
5635
5636 Store byte in AL into ES:[DI]. Update DI.<br><br>Algorithm:
5637 <br><br>
5638 <font face="Fixedsys">
5639 <ul>
5640 <li>ES:[DI] = AL<br></li>
5641 <li>if DF = 0 then
5642         <ul>
5643         <li>DI = DI + 1</li>
5644         </ul>
5645         else
5646         <ul>
5647         <li>DI = DI - 1</li>
5648         </ul>
5649 </li>
5650 </ul>
5651 </font>
5652 Example:
5653 <pre><font face="Fixedsys">
5654 ORG 100h
5655
5656 LEA DI, a1
5657 MOV AL, 12h
5658 MOV CX, 5
5659
5660 REP STOSB
5661
5662 RET
5663
5664 a1 DB 5 dup(0)</font></pre>
5665
5666 <font face="Fixedsys">
5667 <table noshade="" border="1">
5668 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
5669 <tr> <td colspan="6">unchanged</td> </tr>
5670 </tbody></table>
5671 </font>
5672
5673 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5674
5675
5676                         <a name="STOSW">&nbsp;</a>
5677 </td>
5678 </tr>
5679
5680
5681
5682
5683
5684 <tr>
5685 <td>
5686 <font face="Fixedsys">
5687 STOSW
5688 </font>
5689 </td>
5690 <td>No operands</td>
5691 <td>
5692
5693 Store word in AX into ES:[DI]. Update DI.<br><br>Algorithm:
5694 <br><br>
5695 <font face="Fixedsys">
5696 <ul>
5697 <li>ES:[DI] = AX<br></li>
5698 <li>if DF = 0 then
5699         <ul>
5700         <li>DI = DI + 2</li>
5701         </ul>
5702         else
5703         <ul>
5704         <li>DI = DI - 2</li>
5705         </ul>
5706 </li>
5707 </ul>
5708 </font>
5709 Example:
5710 <pre><font face="Fixedsys">
5711 ORG 100h
5712
5713 LEA DI, a1
5714 MOV AX, 1234h
5715 MOV CX, 5
5716
5717 REP STOSW
5718
5719 RET
5720
5721 a1 DW 5 dup(0)</font></pre>
5722
5723 <font face="Fixedsys">
5724 <table noshade="" border="1">
5725 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
5726 <tr> <td colspan="6">unchanged</td> </tr>
5727 </tbody></table>
5728 </font>
5729
5730 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5731
5732
5733                         <a name="SUB">&nbsp;</a>
5734 </td>
5735 </tr>
5736
5737
5738
5739
5740
5741
5742 <tr>
5743 <td>
5744 <font face="Fixedsys">
5745 SUB
5746 </font>
5747 </td>
5748 <td>
5749 <font face="Fixedsys">
5750         <nobr>
5751         REG, memory<br>
5752         memory, REG<br>
5753         REG, REG<br>
5754         memory, immediate<br>
5755         REG, immediate
5756         </nobr>
5757 </font>
5758 </td>
5759 <td>
5760
5761 Subtract.
5762 <br><br>Algorithm:<br><br>
5763 <font face="Fixedsys">
5764 operand1 = operand1 - operand2
5765 </font>
5766 <br><br>
5767 Example:<pre><font face="Fixedsys">MOV AL, 5
5768 SUB AL, 1         ; AL = 4
5769
5770 RET</font></pre>
5771
5772 <font face="Fixedsys">
5773 <table noshade="" border="1">
5774 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
5775 <tr> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> <td>r</td> </tr>
5776 </tbody></table>
5777 </font>
5778
5779 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5780
5781
5782                         <a name="TEST">&nbsp;</a>
5783 </td>
5784 </tr>
5785
5786
5787
5788
5789
5790
5791 <tr>
5792 <td>
5793 <font face="Fixedsys">
5794 TEST
5795 </font>
5796 </td>
5797 <td>
5798 <font face="Fixedsys">
5799         <nobr>
5800         REG, memory<br>
5801         memory, REG<br>
5802         REG, REG<br>
5803         memory, immediate<br>
5804         REG, immediate
5805         </nobr>
5806 </font>
5807 </td>
5808 <td>
5809
5810 Logical AND between all bits of two operands for flags only.
5811 These flags are effected: <b>ZF, SF, PF.</b>
5812 Result is not stored anywhere.<br><br>
5813 These rules apply:<br><br>
5814 <font face="Fixedsys">
5815 1 AND 1 = 1<br>
5816 1 AND 0 = 0<br>
5817 0 AND 1 = 0<br>
5818 0 AND 0 = 0<br>
5819 </font>
5820 <br><br>
5821 Example:<pre><font face="Fixedsys">MOV AL, 00000101b
5822 TEST AL, 1         ; ZF = 0.
5823 TEST AL, 10b       ; ZF = 1.
5824 RET</font></pre>
5825
5826 <font face="Fixedsys">
5827 <table noshade="" border="1">
5828 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> </tr>
5829 <tr> <td>0</td> <td>r</td> <td>r</td> <td>0</td> <td>r</td> </tr>
5830 </tbody></table>
5831 </font>
5832
5833 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5834
5835
5836                         <a name="XCHG">&nbsp;</a>
5837 </td>
5838 </tr>
5839
5840
5841
5842
5843
5844
5845 <tr>
5846 <td>
5847 <font face="Fixedsys">
5848 XCHG
5849 </font>
5850 </td>
5851 <td>
5852 <font face="Fixedsys">
5853         <nobr>
5854         REG, memory<br>
5855         memory, REG<br>
5856         REG, REG
5857         </nobr>
5858 </font>
5859 </td>
5860 <td>
5861
5862 Exchange values of two operands.
5863 <br><br>Algorithm:<br><br>
5864 <font face="Fixedsys">
5865 operand1 &lt; - &gt; operand2
5866 </font>
5867 <br><br>
5868 Example:<pre><font face="Fixedsys">MOV AL, 5
5869 MOV AH, 2
5870 XCHG AL, AH   ; AL = 2, AH = 5
5871 XCHG AL, AH   ; AL = 5, AH = 2
5872 RET</font></pre>
5873
5874 <font face="Fixedsys">
5875 <table noshade="" border="1">
5876 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
5877 <tr> <td colspan="6">unchanged</td> </tr>
5878 </tbody></table>
5879 </font>
5880
5881 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5882
5883
5884                         <a name="XLATB">&nbsp;</a>
5885 </td>
5886 </tr>
5887
5888
5889
5890
5891
5892
5893 <tr>
5894 <td>
5895 <font face="Fixedsys">
5896 XLATB
5897 </font>
5898 </td>
5899 <td>No operands</td>
5900 <td>
5901
5902 Translate byte from table.<br>
5903 Copy value of memory byte at <nobr>DS:[BX + unsigned AL]</nobr> to
5904 AL register.
5905 <br><br>Algorithm:<br><br>
5906 <font face="Fixedsys">
5907 AL = DS:[BX + unsigned AL]
5908 </font>
5909 <br><br>
5910 Example:<pre><font face="Fixedsys">
5911 ORG 100h
5912 LEA BX, dat
5913 MOV AL, 2
5914 XLATB     ; AL = 33h
5915
5916 RET
5917
5918 dat DB 11h, 22h, 33h, 44h, 55h</font></pre>
5919
5920 <font face="Fixedsys">
5921 <table noshade="" border="1">
5922 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
5923 <tr> <td colspan="6">unchanged</td> </tr>
5924 </tbody></table>
5925 </font>
5926
5927 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5928
5929
5930                         <a name="XOR">&nbsp;</a>
5931 </td>
5932 </tr>
5933
5934
5935
5936
5937
5938
5939
5940 <tr>
5941 <td>
5942 <font face="Fixedsys">
5943 XOR
5944 </font>
5945 </td>
5946 <td>
5947 <font face="Fixedsys">
5948         <nobr>
5949         REG, memory<br>
5950         memory, REG<br>
5951         REG, REG<br>
5952         memory, immediate<br>
5953         REG, immediate
5954         </nobr>
5955 </font>
5956 </td>
5957 <td>
5958
5959 Logical XOR (Exclusive OR) between all bits of two operands.
5960 Result is stored in first operand.<br><br>
5961 These rules apply:<br><br>
5962 <font face="Fixedsys">
5963 1 XOR 1 = 0<br>
5964 1 XOR 0 = 1<br>
5965 0 XOR 1 = 1<br>
5966 0 XOR 0 = 0<br>
5967 </font>
5968 <br><br>
5969 Example:<pre><font face="Fixedsys">MOV AL, 00000111b
5970 XOR AL, 00000010b    ; AL = 00000101b
5971 RET</font></pre>
5972
5973
5974 <font face="Fixedsys">
5975 <table noshade="" border="1">
5976 <tbody><tr> <td>C</td> <td>Z</td> <td>S</td> <td>O</td> <td>P</td> <td>A</td> </tr>
5977 <tr> <td>0</td> <td>r</td> <td>r</td> <td>0</td> <td>r</td> <td>?</td> </tr>
5978 </tbody></table>
5979 </font>
5980
5981
5982 <a href="#top1"><img src="8086_instruction_set_files/back_to_top.gif" alt="Back to Top" align="right" border="0" width="41" height="36"></a>
5983
5984
5985 </td>
5986 </tr>
5987
5988
5989
5990
5991
5992 </tbody></table>
5993
5994 <br><br>
5995
5996 </font><hr>
5997
5998 <font size="3" face="Verdana"><br><br><br>
5999 </font><center>
6000 <font size="3" face="Verdana"><font size="2">
6001 copyright © <font size="1">2005</font> <a href="http://www.emu8086.com/">emu8086.com</a><br>
6002 all rights reserved.<br>
6003
6004 </font>
6005 </font></center>
6006
6007 <font size="3" face="Verdana"></font>
6008
6009
6010 <br>
6011
6012 <iframe src="8086_instruction_set_files/z_bot_menu.html" marginwidth="0" marginheight="0" align="middle" scrolling="auto" width="100%" frameborder="0" height="100"></iframe><br>
6013
6014 </body></html>