src/libs/x86emu/debug.c

   1 /****************************************************************************
   2 *
   3 *                                               Realmode X86 Emulator Library
   4 *
   5 *               Copyright (C) 1996-1999 SciTech Software, Inc.
   6 *                                    Copyright (C) David Mosberger-Tang
   7 *                                          Copyright (C) 1999 Egbert Eich
   8 *
   9 *  ========================================================================
  10 *
  11 *  Permission to use, copy, modify, distribute, and sell this software and
  12 *  its documentation for any purpose is hereby granted without fee,
  13 *  provided that the above copyright notice appear in all copies and that
  14 *  both that copyright notice and this permission notice appear in
  15 *  supporting documentation, and that the name of the authors not be used
  16 *  in advertising or publicity pertaining to distribution of the software
  17 *  without specific, written prior permission.  The authors makes no
  18 *  representations about the suitability of this software for any purpose.
  19 *  It is provided "as is" without express or implied warranty.
  20 *
  21 *  THE AUTHORS DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
  22 *  INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
  23 *  EVENT SHALL THE AUTHORS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
  24 *  CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
  25 *  USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
  26 *  OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  27 *  PERFORMANCE OF THIS SOFTWARE.
  28 *
  29 *  ========================================================================
  30 *
  31 * Language:             ANSI C
  32 * Environment:  Any
  33 * Developer:    Kendall Bennett
  34 *
  35 * Description:  This file contains the code to handle debugging of the
  36 *                               emulator.
  37 *
  38 ****************************************************************************/
  39
  40 #include "x86emu/x86emui.h"
  41 #include <stdio.h>
  42 #include <string.h>
  43 #ifndef NO_SYS_HEADERS
  44 #include <stdarg.h>
  45 #include <stdlib.h>
  46 #endif
  47
  48 /*----------------------------- Implementation ----------------------------*/
  49
  50 #ifdef DEBUG
  51
  52 static void print_encoded_bytes(u16 s, u16 o);
  53 static void print_decoded_instruction(void);
  54 static int parse_line(char *s, int *ps, int *n);
  55
  56 /* should look something like debug's output. */
  57 void
  58 X86EMU_trace_regs(void)
  59 {
  60     if (DEBUG_TRACE()) {
  61         x86emu_dump_regs();
  62     }
  63     if (DEBUG_DECODE() && !DEBUG_DECODE_NOPRINT()) {
  64         printk("%04x:%04x ", M.x86.saved_cs, M.x86.saved_ip);
  65         print_encoded_bytes(M.x86.saved_cs, M.x86.saved_ip);
  66         print_decoded_instruction();
  67     }
  68 }
  69
  70 void
  71 X86EMU_trace_xregs(void)
  72 {
  73     if (DEBUG_TRACE()) {
  74         x86emu_dump_xregs();
  75     }
  76 }
  77
  78 void
  79 x86emu_just_disassemble(void)
  80 {
  81     /*
  82      * This routine called if the flag DEBUG_DISASSEMBLE is set kind
  83      * of a hack!
  84      */
  85     printk("%04x:%04x ", M.x86.saved_cs, M.x86.saved_ip);
  86     print_encoded_bytes(M.x86.saved_cs, M.x86.saved_ip);
  87     print_decoded_instruction();
  88 }
  89
  90 static void
  91 disassemble_forward(u16 seg, u16 off, int n)
  92 {
  93     X86EMU_sysEnv tregs;
  94     int i;
  95     u8 op1;
  96
  97     /*
  98      * hack, hack, hack.  What we do is use the exact machinery set up
  99      * for execution, except that now there is an additional state
 100      * flag associated with the "execution", and we are using a copy
 101      * of the register struct.  All the major opcodes, once fully
 102      * decoded, have the following two steps: TRACE_REGS(r,m);
 103      * SINGLE_STEP(r,m); which disappear if DEBUG is not defined to
 104      * the preprocessor.  The TRACE_REGS macro expands to:
 105      *
 106      * if (debug&DEBUG_DISASSEMBLE)
 107      *     {just_disassemble(); goto EndOfInstruction;}
 108      *     if (debug&DEBUG_TRACE) trace_regs(r,m);
 109      *
 110      * ......  and at the last line of the routine.
 111      *
 112      * EndOfInstruction: end_instr();
 113      *
 114      * Up to the point where TRACE_REG is expanded, NO modifications
 115      * are done to any register EXCEPT the IP register, for fetch and
 116      * decoding purposes.
 117      *
 118      * This was done for an entirely different reason, but makes a
 119      * nice way to get the system to help debug codes.
 120      */
 121     tregs = M;
 122     tregs.x86.R_IP = off;
 123     tregs.x86.R_CS = seg;
 124
 125     /* reset the decoding buffers */
 126     tregs.x86.enc_str_pos = 0;
 127     tregs.x86.enc_pos = 0;
 128
 129     /* turn on the "disassemble only, no execute" flag */
 130     tregs.x86.debug |= DEBUG_DISASSEMBLE_F;
 131
 132     /* DUMP NEXT n instructions to screen in straight_line fashion */
 133     /*
 134      * This looks like the regular instruction fetch stream, except
 135      * that when this occurs, each fetched opcode, upon seeing the
 136      * DEBUG_DISASSEMBLE flag set, exits immediately after decoding
 137      * the instruction.  XXX --- CHECK THAT MEM IS NOT AFFECTED!!!
 138      * Note the use of a copy of the register structure...
 139      */
 140     for (i = 0; i < n; i++) {
 141         op1 = (*sys_rdb) (((u32) M.x86.R_CS << 4) + (M.x86.R_IP++));
 142         (x86emu_optab[op1]) (op1);
 143     }
 144     /* end major hack mode. */
 145 }
 146
 147 void
 148 x86emu_check_ip_access(void)
 149 {
 150     /* NULL as of now */
 151 }
 152
 153 void
 154 x86emu_check_sp_access(void)
 155 {
 156 }
 157
 158 void
 159 x86emu_check_mem_access(u32 dummy)
 160 {
 161     /*  check bounds, etc */
 162 }
 163
 164 void
 165 x86emu_check_data_access(uint dummy1, uint dummy2)
 166 {
 167     /*  check bounds, etc */
 168 }
 169
 170 void
 171 x86emu_inc_decoded_inst_len(int x)
 172 {
 173     M.x86.enc_pos += x;
 174 }
 175
 176 void
 177 x86emu_decode_printf(const char *x)
 178 {
 179     sprintf(M.x86.decoded_buf + M.x86.enc_str_pos, "%s", x);
 180     M.x86.enc_str_pos += strlen(x);
 181 }
 182
 183 void
 184 x86emu_decode_printf2(const char *x, int y)
 185 {
 186     char temp[100];
 187
 188     snprintf(temp, sizeof(temp), x, y);
 189     sprintf(M.x86.decoded_buf + M.x86.enc_str_pos, "%s", temp);
 190     M.x86.enc_str_pos += strlen(temp);
 191 }
 192
 193 void
 194 x86emu_end_instr(void)
 195 {
 196     M.x86.enc_str_pos = 0;
 197     M.x86.enc_pos = 0;
 198 }
 199
 200 static void
 201 print_encoded_bytes(u16 s, u16 o)
 202 {
 203     int i;
 204     char buf1[64];
 205
 206     for (i = 0; i < M.x86.enc_pos; i++) {
 207         sprintf(buf1 + 2 * i, "%02x", fetch_data_byte_abs(s, o + i));
 208     }
 209     printk("%-20s", buf1);
 210 }
 211
 212 static void
 213 print_decoded_instruction(void)
 214 {
 215     printk("%s", M.x86.decoded_buf);
 216 }
 217
 218 void
 219 x86emu_print_int_vect(u16 iv)
 220 {
 221     u16 seg, off;
 222
 223     if (iv > 256)
 224         return;
 225     seg = fetch_data_word_abs(0, iv * 4);
 226     off = fetch_data_word_abs(0, iv * 4 + 2);
 227     printk("%04x:%04x ", seg, off);
 228 }
 229
 230 void
 231 X86EMU_dump_memory(u16 seg, u16 off, u32 amt)
 232 {
 233     u32 start = off & 0xfffffff0;
 234     u32 end = (off + 16) & 0xfffffff0;
 235     u32 i;
 236     u32 current;
 237
 238     current = start;
 239     while (end <= off + amt) {
 240         printk("%04x:%04x ", seg, start);
 241         for (i = start; i < off; i++)
 242             printk("   ");
 243         for (; i < end; i++)
 244             printk("%02x ", fetch_data_byte_abs(seg, i));
 245         printk("\n");
 246         start = end;
 247         end = start + 16;
 248     }
 249 }
 250
 251 void
 252 x86emu_single_step(void)
 253 {
 254         return;
 255     char s[1024];
 256     int ps[10];
 257     int ntok;
 258     int cmd;
 259     int done;
 260     int segment;
 261     int offset;
 262     static int breakpoint;
 263     static int noDecode = 1;
 264
 265     //char *p;
 266
 267     if (DEBUG_BREAK()) {
 268         if (M.x86.saved_ip != breakpoint) {
 269             return;
 270         }
 271         else {
 272             M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
 273             M.x86.debug |= DEBUG_TRACE_F;
 274             M.x86.debug &= ~DEBUG_BREAK_F;
 275             print_decoded_instruction();
 276             X86EMU_trace_regs();
 277         }
 278     }
 279     done = 0;
 280     offset = M.x86.saved_ip;
 281     while (!done) {
 282         printk("-");
 283         //p = fgets(s, 1023, stdin);
 284         cmd = parse_line(s, ps, &ntok);
 285         switch (cmd) {
 286         case 'u':
 287             disassemble_forward(M.x86.saved_cs, (u16) offset, 10);
 288             break;
 289         case 'd':
 290             if (ntok == 2) {
 291                 segment = M.x86.saved_cs;
 292                 offset = ps[1];
 293                 X86EMU_dump_memory(segment, (u16) offset, 16);
 294                 offset += 16;
 295             }
 296             else if (ntok == 3) {
 297                 segment = ps[1];
 298                 offset = ps[2];
 299                 X86EMU_dump_memory(segment, (u16) offset, 16);
 300                 offset += 16;
 301             }
 302             else {
 303                 segment = M.x86.saved_cs;
 304                 X86EMU_dump_memory(segment, (u16) offset, 16);
 305                 offset += 16;
 306             }
 307             break;
 308         case 'c':
 309             M.x86.debug ^= DEBUG_TRACECALL_F;
 310             break;
 311         case 's':
 312             M.x86.debug ^= DEBUG_SVC_F | DEBUG_SYS_F | DEBUG_SYSINT_F;
 313             break;
 314         case 'r':
 315             X86EMU_trace_regs();
 316             break;
 317         case 'x':
 318             X86EMU_trace_xregs();
 319             break;
 320         case 'g':
 321             if (ntok == 2) {
 322                 breakpoint = ps[1];
 323                 if (noDecode) {
 324                     M.x86.debug |= DEBUG_DECODE_NOPRINT_F;
 325                 }
 326                 else {
 327                     M.x86.debug &= ~DEBUG_DECODE_NOPRINT_F;
 328                 }
 329                 M.x86.debug &= ~DEBUG_TRACE_F;
 330                 M.x86.debug |= DEBUG_BREAK_F;
 331                 done = 1;
 332             }
 333             break;
 334         case 'q':
 335             M.x86.debug |= DEBUG_EXIT;
 336             return;
 337         case 'P':
 338             noDecode = (noDecode) ? 0 : 1;
 339             printk("Toggled decoding to %s\n", (noDecode) ? "FALSE" : "TRUE");
 340             break;
 341         case 't':
 342         case 0:
 343             done = 1;
 344             break;
 345         }
 346     }
 347 }
 348
 349 int
 350 X86EMU_trace_on(void)
 351 {
 352     return M.x86.debug |= DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F;
 353 }
 354
 355 int
 356 X86EMU_trace_off(void)
 357 {
 358     return M.x86.debug &= ~(DEBUG_STEP_F | DEBUG_DECODE_F | DEBUG_TRACE_F);
 359 }
 360
 361 static int
 362 parse_line(char *s, int *ps, int *n)
 363 {
 364     int cmd;
 365
 366     *n = 0;
 367     while (*s == ' ' || *s == '\t')
 368         s++;
 369     ps[*n] = *s;
 370     switch (*s) {
 371     case '\n':
 372         *n += 1;
 373         return 0;
 374     default:
 375         cmd = *s;
 376         *n += 1;
 377     }
 378
 379     while (1) {
 380         while (*s != ' ' && *s != '\t' && *s != '\n')
 381             s++;
 382
 383         if (*s == '\n')
 384             return cmd;
 385
 386         while (*s == ' ' || *s == '\t')
 387             s++;
 388
 389         //sscanf(s, "%x", &ps[*n]);
 390         *n += 1;
 391     }
 392 }
 393
 394 #endif                          /* DEBUG */
 395
 396 void
 397 x86emu_dump_regs(void)
 398 {
 399     printk("\tAX=%04x  ", M.x86.R_AX);
 400     printk("BX=%04x  ", M.x86.R_BX);
 401     printk("CX=%04x  ", M.x86.R_CX);
 402     printk("DX=%04x  ", M.x86.R_DX);
 403     printk("SP=%04x  ", M.x86.R_SP);
 404     printk("BP=%04x  ", M.x86.R_BP);
 405     printk("SI=%04x  ", M.x86.R_SI);
 406     printk("DI=%04x\n", M.x86.R_DI);
 407     printk("\tDS=%04x  ", M.x86.R_DS);
 408     printk("ES=%04x  ", M.x86.R_ES);
 409     printk("SS=%04x  ", M.x86.R_SS);
 410     printk("CS=%04x  ", M.x86.R_CS);
 411     printk("IP=%04x   ", M.x86.R_IP);
 412     if (ACCESS_FLAG(F_OF))
 413         printk("OV ");          /* CHECKED... */
 414     else
 415         printk("NV ");
 416     if (ACCESS_FLAG(F_DF))
 417         printk("DN ");
 418     else
 419         printk("UP ");
 420     if (ACCESS_FLAG(F_IF))
 421         printk("EI ");
 422     else
 423         printk("DI ");
 424     if (ACCESS_FLAG(F_SF))
 425         printk("NG ");
 426     else
 427         printk("PL ");
 428     if (ACCESS_FLAG(F_ZF))
 429         printk("ZR ");
 430     else
 431         printk("NZ ");
 432     if (ACCESS_FLAG(F_AF))
 433         printk("AC ");
 434     else
 435         printk("NA ");
 436     if (ACCESS_FLAG(F_PF))
 437         printk("PE ");
 438     else
 439         printk("PO ");
 440     if (ACCESS_FLAG(F_CF))
 441         printk("CY ");
 442     else
 443         printk("NC ");
 444     printk("\n");
 445 }
 446
 447 void
 448 x86emu_dump_xregs(void)
 449 {
 450     printk("\tEAX=%08x  ", M.x86.R_EAX);
 451     printk("EBX=%08x  ", M.x86.R_EBX);
 452     printk("ECX=%08x  ", M.x86.R_ECX);
 453     printk("EDX=%08x  \n", M.x86.R_EDX);
 454     printk("\tESP=%08x  ", M.x86.R_ESP);
 455     printk("EBP=%08x  ", M.x86.R_EBP);
 456     printk("ESI=%08x  ", M.x86.R_ESI);
 457     printk("EDI=%08x\n", M.x86.R_EDI);
 458     printk("\tDS=%04x  ", M.x86.R_DS);
 459     printk("ES=%04x  ", M.x86.R_ES);
 460     printk("SS=%04x  ", M.x86.R_SS);
 461     printk("CS=%04x  ", M.x86.R_CS);
 462     printk("EIP=%08x\n\t", M.x86.R_EIP);
 463     if (ACCESS_FLAG(F_OF))
 464         printk("OV ");          /* CHECKED... */
 465     else
 466         printk("NV ");
 467     if (ACCESS_FLAG(F_DF))
 468         printk("DN ");
 469     else
 470         printk("UP ");
 471     if (ACCESS_FLAG(F_IF))
 472         printk("EI ");
 473     else
 474         printk("DI ");
 475     if (ACCESS_FLAG(F_SF))
 476         printk("NG ");
 477     else
 478         printk("PL ");
 479     if (ACCESS_FLAG(F_ZF))
 480         printk("ZR ");
 481     else
 482         printk("NZ ");
 483     if (ACCESS_FLAG(F_AF))
 484         printk("AC ");
 485     else
 486         printk("NA ");
 487     if (ACCESS_FLAG(F_PF))
 488         printk("PE ");
 489     else
 490         printk("PO ");
 491     if (ACCESS_FLAG(F_CF))
 492         printk("CY ");
 493     else
 494         printk("NC ");
 495     printk("\n");
 496 }