sdcc/src/z80/peeph-sm83.def

   1 // peeph-sm83.def - SM83 peephole rules
   2 //
   3 //
   4 // (c) Philipp Klaus Krause (pkk@spth.de, philipp@colecovision.eu) 2006 - 2007
   5 // (c) Sebastian 'basxto' Riedel (sdcc@basxto.de) 2020 - 2022
   6 //
   7 // This program is free software; you can redistribute it and/or modify it
   8 // under the terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 2, or (at your option) any
  10 // later version.
  11 //
  12 // This program is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16 //
  17 // You should have received a copy of the GNU General Public License
  18 // along with this program; if not, write to the Free Software
  19 // Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  20
  21 replace{
  22         ld      hl, #%1
  23         ld      a, (hl)
  24 } by {
  25         ; sm83 peephole 0 used ldh instead of ld a, (hl).
  26         ldh     a, (#%1)
  27 } if operandsLiteral(%1), immdInRange(0xff00 0xffff '|' %1 0 %2), notUsed('hl')
  28
  29 replace{
  30         ld      a, (#%1)
  31 } by {
  32         ; sm83 peephole 0b used ldh instead of ld.
  33         ldh     a, (#%1)
  34 } if operandsLiteral(%1), immdInRange(0xff00 0xffff '|' %1 0 %2)
  35
  36 replace{
  37         ld      hl, #%1
  38         ld      (hl), a
  39 } by {
  40         ; sm83 peephole 1 used ldh instead of ld (hl), a.
  41         ldh     (#%1), a
  42 } if operandsLiteral(%1), immdInRange(0xff00 0xffff '|' %1 0 %2), notUsed('hl')
  43
  44 replace{
  45         ld      (#%1), a
  46 } by {
  47         ; sm83 peephole 1b used ldh instead of ld.
  48         ldh     (#%1), a
  49 } if operandsLiteral(%1), immdInRange(0xff00 0xffff '|' %1 0 %2)
  50
  51 replace {
  52         ld      a, (hl)
  53         inc     hl
  54 } by {
  55         ld      a, (hl+)
  56         ; sm83 peephole 2 used ldi to increment hl after load
  57 }
  58
  59 replace {
  60         ld      %1, (hl)
  61         inc     hl
  62 } by {
  63         ld      a, (hl+)
  64         ld      %1, a
  65         ; sm83 peephole 2b used ldi to increment hl after load
  66 } if notUsed('a')
  67
  68 replace {
  69         ld      %1, (hl)
  70         dec     hl
  71 } by {
  72         ld      a, (hl-)
  73         ld      %1, a
  74         ; sm83 peephole 3 used ldd to decrement hl after load
  75 } if notUsed('a')
  76
  77 replace {
  78         ld      a, (hl)
  79         dec     hl
  80 } by {
  81         ld      a, (hl-)
  82         ; sm83 peephole 3b used ldd to decrement hl after load
  83 }
  84
  85 replace {
  86         ld      (hl), a
  87         inc     hl
  88 } by {
  89         ld      (hl+), a
  90         ; sm83 peephole 4 used ldi to increment hl after load
  91 }
  92
  93 replace {
  94         ld      (hl), %1
  95         inc     hl
  96 } by {
  97         ld      a, %1
  98         ld      (hl+), a
  99         ; sm83 peephole 4b used ldi to increment hl after load
 100 } if notUsed('a')
 101
 102 replace {
 103         ld      (hl), a
 104         dec     hl
 105 } by {
 106         ld      (hl-), a
 107         ; sm83 peephole 5 used ldd to decrement hl after load
 108 }
 109
 110 replace {
 111         ld      (hl), %1
 112         dec     hl
 113 } by {
 114         ld      a, %1
 115         ld      (hl-), a
 116         ; sm83 peephole 5b used ldd to decrement hl after load
 117 } if notUsed('a')
 118
 119 replace {
 120         ld      (hl), a
 121         inc     %2
 122         ld      a, (%2)
 123         inc     hl
 124 } by {
 125         ld      (hl+), a
 126         ; sm83 peephole 7 used ldi to increment hl
 127         inc     %2
 128         ld      a, (%2)
 129 } if notSame('hl' %2)
 130
 131 replace {
 132         ld      a, (hl)
 133         ld      (%2), a
 134         inc     %2
 135         inc     hl
 136 } by {
 137         ld      a, (hl+)
 138         ; sm83 peephole 8 used ldi to increment hl
 139         ld      (%2), a
 140         inc     %2
 141 } if notSame('hl' %2)
 142
 143 replace {
 144         dec     hl
 145         ld      a, (hl+)
 146         ld      h, (hl)
 147         ld      l, a
 148 } by {
 149         ; sm83 peephole 9 reversed loading order of hl
 150         ld      a, (hl-)
 151         ld      l, (hl)
 152         ld      h, a
 153 } if notUsed('a')
 154
 155 replace restart {
 156         ldhl    sp,#%1
 157         ld      %2, %3
 158         ldhl    sp,#%1
 159 } by {
 160         ; sm83 peephole 10a removed redundant ldhl.
 161         ldhl    sp,#%1
 162         ld      %2, %3
 163 } if notSame('(hl+)' %2 %3),  notSame('(hl+)' %2 %3)
 164
 165 // 10b and c are for pushing stack addresses
 166 replace restart {
 167         ldhl    sp,     #%1
 168         ld      %3, %4
 169         ld      %5, %6
 170         ldhl    sp,     #%2
 171 } by {
 172         ldhl    sp,     #1
 173         ld      %3, %4
 174         ld      %5, %6
 175         ; sm83 peephole 10b turned ldhl into dec hl
 176         dec     hl
 177 } if operandsLiteral(%1 %2), notSame('l' %3 %5), notSame('l' %3 %5), immdInRange(0x01 0x01 '-' %1 %2 %3), operandsNotRelated('hl' %3 %4 %5 %6)
 178
 179 replace restart {
 180         ldhl    sp,     #%1
 181         ld      %3, %4
 182         ld      %5, %6
 183         ldhl    sp,     #%2
 184 } by {
 185         ldhl    sp,     #1
 186         ld      %3, %4
 187         ld      %5, %6
 188         ; sm83 peephole 10c turned ldhl into inc hl
 189         inc     hl
 190 } if operandsLiteral(%1 %2), notSame('l' %3 %5), notSame('l' %3 %5), immdInRange(0x01 0x01 '-' %2 %1 %3), operandsNotRelated('hl' %3 %4 %5 %6)
 191
 192 replace restart {
 193         ldhl    sp,#%1
 194         dec     hl
 195 } by {
 196         ; sm83 peephole 10d combined ld and dec.
 197         ldhl    sp,#%2
 198 } if immdInRange(-128 127 '-' %1 1 %2)
 199
 200 replace restart {
 201         ldhl    sp,#%1
 202         inc     hl
 203 } by {
 204         ; sm83 peephole 10e combined ld and inc.
 205         ldhl    sp,#%2
 206 } if immdInRange(-128 127 '+' %1 1 %2)
 207
 208 replace restart {
 209         and     a, #%1
 210         swap a
 211         and     a, #%2
 212 } by {
 213         ; sm83 peephole 11 combined redundant ANDs #%2 and swapped #%1.
 214         swap a
 215         and     a, #%7
 216 } if operandsLiteral(%1 %2), immdInRange(0x00 0xff '/' %1 0x10 %3), immdInRange(0x00 0xfff '*' %1 0x10 %4), immdInRange(0x00 0xff '&' %4 0xF0 %5), immdInRange(0x00 0xff '|' %3 %5 %6), immdInRange(0x00 0xff '&' %2 %6 %x7)
 217
 218 replace restart {
 219         ldh a, (%1)
 220         inc a
 221         ldh (%1), a
 222 } by {
 223         ; sm83 peephole 12 turned ldh into inc (hl).
 224         ld hl, #((%1) | 0xFF00)
 225         inc (hl)
 226 } if notSame(%1 'c'), notUsed('a' 'hl')
 227
 228 replace restart {
 229         ldh a, (%1)
 230         dec a
 231         ldh (%1), a
 232 } by {
 233         ; sm83 peephole 13 turned ldh into dec (hl).
 234         ld hl, #((%1) | 0xFF00)
 235         dec (hl)
 236 } if notSame(%1 'c'), notUsed('a' 'hl')
 237
 238 replace restart {
 239         ldh a, (%1)
 240         srl a
 241         ldh (%1), a
 242 } by {
 243         ; sm83 peephole 14 turned ldh into srl (hl).
 244         ld hl, #((%1) | 0xFF00)
 245         srl (hl)
 246 } if notSame(%1 'c'), notUsed('a' 'hl')
 247
 248 replace restart {
 249         rra
 250         rla
 251 } by {
 252         ; sm83 peephole 16 removed redundant rra/rla
 253 } if notUsed('cf' 'hf' 'nf' 'zf')
 254
 255 replace {
 256         xor     a, a
 257         push    af
 258         inc     sp
 259         xor     a, a
 260         push    af
 261         inc     sp
 262 } by {
 263         ; sm83 peephole 17a pushed double `xor a` fast
 264         xor     a, a
 265         rrca
 266         push    af
 267         xor     a, a
 268 }
 269
 270 //TODO: fails for unknown reasons
 271 //replace {
 272 //      ld      %1, #%2
 273 //      push    %1
 274 //} by {
 275 //      ; sm83 peephole 17b pushed #%2 faster
 276 //      xor     a, a
 277 //      rra
 278 //      push    af
 279 //} if operandsLiteral(%2), immdInRange(0 0 '+' %2 0 %3), notUsed(%1 'af')
 280
 281 replace {
 282         ld      %1, #%2
 283         push    %1
 284 } by {
 285         ; sm83 peephole 18a pushed #%2 faster
 286         sub     a, a
 287         push    af
 288 } if operandsLiteral(%2), immdInRange(0x00C0 0x00C0 '+' %2 0 %x3), notUsed(%1 'af')
 289
 290
 291 // Those rules save 1 byte and 4 cycles each
 292 replace {
 293         ld      %1, #%2
 294         push    %1
 295 } by {
 296         ; sm83 peephole 18b pushed #%2 faster
 297         xor     a, a
 298         push    af
 299 } if operandsLiteral(%2), immdInRange(0x0080 0x0080 '+' %2 0 %x3), notUsed(%1 'af')
 300
 301 replace {
 302         ld      %1, #%2
 303         push    %1
 304 } by {
 305         ; sm83 peephole 18c pushed #%2 faster
 306         xor     a, a
 307         scf
 308         push    af
 309 } if operandsLiteral(%2), immdInRange(0x0090 0x0090 '+' %2 0 %x3), notUsed(%1 'af')
 310
 311 replace {
 312         ld      %1, #%2
 313         push    %1
 314 } by {
 315         ; sm83 peephole 18d pushed #%2 faster
 316         xor     a, a
 317         and     a
 318         push    af
 319 } if operandsLiteral(%2), immdInRange(0x00A0 0x00A0 '+' %2 0 %x3), notUsed(%1 'af')
 320
 321 replace {
 322         ld      %1, #%2
 323         push    %1
 324 } by {
 325         ; sm83 peephole 18e pushed #%2 faster
 326         xor     a, a
 327         scf
 328         push    af
 329 } if operandsLiteral(%2), immdInRange(0x00D0 0x00D0 '+' %2 0 %x3), notUsed(%1 'af')
 330
 331 replace {
 332         ld      %1, #%2
 333         push    %1
 334 } by {
 335         ; sm83 peephole 18f pushed #%2 faster
 336         xor     a, a
 337         inc     a
 338         push    af
 339 } if operandsLiteral(%2), immdInRange(0x0100 0x0100 '+' %2 0 %x3), notUsed(%1 'af')
 340
 341 replace {
 342         ld      %1, #%2
 343         push    %1
 344 } by {
 345         ; sm83 peephole 18g pushed #%2 faster
 346         scf
 347         sbc     a, a
 348         push    af
 349 } if operandsLiteral(%2), immdInRange(0xFF30 0xFF30 '+' %2 0 %x3), notUsed(%1 'af')
 350
 351 replace {
 352         ld      %1, #%2
 353         push    %1
 354 } by {
 355         ; sm83 peephole 18h pushed #%2 faster
 356         xor     a, a
 357         dec     a
 358         push    af
 359 } if operandsLiteral(%2), immdInRange(0xFF60 0xFF60 '+' %2 0 %x3), notUsed(%1 'af')
 360
 361 replace {
 362         push    af
 363         inc     sp
 364         ld      a, #%2
 365         push    af
 366         inc     sp
 367 } by {
 368         ; sm83 peephole 19 pushed #%2 via flags
 369         cp      a
 370         push    af
 371 } if operandsLiteral(%2), immdInRange(0xC0 0xC0 '+' %2 0 %x3), notUsed('f')
 372
 373 replace restart {
 374         inc     hl
 375         ld      a, (hl-)
 376         or      a, (hl)
 377 } by {
 378         ld      a, (hl+)
 379         or      a, (hl)
 380         ; sm83 peephole 20 reversed ld and or.
 381 } if notUsed('hl')
 382
 383 replace restart {
 384 %1:
 385         ld      a, (hl+)
 386         ld      %3, a
 387         ld      a, (%6)
 388         inc     %6
 389         sub     a, %3
 390         ld      %4, a
 391         jp      NZ, %2
 392         or      a,%3
 393         jp      NZ, %1
 394 %2:
 395 } by {
 396 %1:
 397         ld      a, (hl+)
 398         ld      %3, a
 399         ld      a, (%6)
 400         inc     %6
 401         sub     a, %3
 402         jp      NZ, %2
 403         cp      a,%3
 404         jp      NZ, %1
 405 %2:
 406         ; sm83 peephole 21 sped up loop body.
 407         ld      %4, a
 408 } if canSplitReg(%6 %9 %10), operandsNotRelated(%3 %6 'hl'), operandsNotRelated(%3 %6 'hl'), notSame(%3 %4), labelRefCount(%2 1)
 409
 410 replace restart {
 411         ld      (hl+), a
 412         ld      (hl), %1
 413         ld      a, (hl-)
 414         or      a, (hl)
 415 } by {
 416         ld      (hl+), a
 417         ld      (hl), %1
 418         ; sm83 peephole 22 remove unnecessary load back
 419         or      a, %1
 420         dec     hl
 421 }
 422
 423 replace {
 424         pop     %1
 425         push    %1
 426 } by {
 427         ; peephole sp1 removed not needed push
 428         pop     %1
 429 } if notUsed('sp')
 430
 431 replace {
 432         pop     %1
 433         pop     %2
 434         push    %2
 435         push    %1
 436 } by {
 437         ; peephole sp2 removed not needed push
 438         pop     %1
 439         pop     %2
 440 } if notUsed('sp'), notSame(%1 %2)
 441
 442 replace {
 443         add     sp, %1
 444 } by {
 445         ; peephole sp3 removed not needed add sp
 446 } if notUsed('sp')
 447
 448 replace {
 449         pop     %1
 450 } by {
 451         ; peephole sp6 removed not needed pop
 452 } if notUsed(%1), notUsed('sp')
 453
 454 // for 2B it wouldn't be worth it
 455 replace {
 456         inc     sp
 457         inc     sp
 458         inc     sp
 459 } by {
 460         ; peephole sp7 increased SP by addition
 461         add     sp, #3
 462 } if notUsed('f')
 463
 464 replace restart {
 465         add     sp, #%1
 466         inc     sp
 467 } by {
 468         ; peephole sp8a increased SP by addition
 469         add     sp, #%2
 470 } if immdInRange(-128 127 '+' %1 1 %2), notUsed('hf' 'cf')
 471
 472 replace restart {
 473         inc     sp
 474         add     sp, #%1
 475 } by {
 476         ; peephole sp8b increased SP by addition
 477         add     sp, #%2
 478 } if immdInRange(-128 127 '+' %1 1 %2)
 479
 480 replace restart {
 481         add     sp, #%1
 482         add     sp, #%2
 483 } by {
 484         ; peephole sp9 combined SP additions
 485         add     sp, #%3
 486 } if immdInRange(-128 127 '+' %1 %2 %3), notUsed('hf' 'cf')
 487
 488 // only handle stack adjustment after calls to not
 489 // disturb detection of uninitialized reads in emulators
 490 replace {
 491         call    %2
 492         add     sp, #%1
 493 } by {
 494         call    %2
 495         ; peephole sp10a increased SP by %1 through pop
 496         pop     %3
 497 } if immdInRange(2 2 '+' %1 0 %2), unusedReg(%3 'bc' 'de' 'hl'), notUsed('f')
 498
 499 // unusedReg does not support 'af'
 500 replace {
 501         call    %2
 502         add     sp, #%1
 503 } by {
 504         call    %2
 505         ; peephole sp10b increased SP by %1 through pop
 506         pop     af
 507 } if immdInRange(2 2 '+' %1 0 %2), notUsed('af')
 508
 509 // if f was used
 510 replace {
 511         call    %2
 512         inc     sp
 513         inc     sp
 514 } by {
 515         call    %2
 516         ; peephole sp10c increased SP by 2 through pop
 517         pop     %3
 518 } if unusedReg(%3 'bc' 'de' 'hl')