insns.pl

   1 #!/usr/bin/perl
   2 #
   3 # insns.pl   produce insnsa.c, insnsd.c, insnsi.h, insnsn.c from insns.dat
   4 #
   5 # The Netwide Assembler is copyright (C) 1996 Simon Tatham and
   6 # Julian Hall. All rights reserved. The software is
   7 # redistributable under the license given in the file "LICENSE"
   8 # distributed in the NASM archive.
   9
  10 # Opcode prefixes which need their own opcode tables
  11 # LONGER PREFIXES FIRST!
  12 @disasm_prefixes = qw(0F24 0F25 0F38 0F3A 0F7A 0FA6 0FA7 0F);
  13
  14 # This should match MAX_OPERANDS from nasm.h
  15 $MAX_OPERANDS = 5;
  16
  17 # Add VEX prefixes
  18 @vexlist = ();
  19 for ($m = 0; $m < 32; $m++) {
  20     for ($lp = 0; $lp < 8; $lp++) {
  21         push(@vexlist, sprintf("VEX%02X%01X", $m, $lp));
  22     }
  23 }
  24 @disasm_prefixes = (@vexlist, @disasm_prefixes);
  25
  26 print STDERR "Reading insns.dat...\n";
  27
  28 @args   = ();
  29 undef $output;
  30 foreach $arg ( @ARGV ) {
  31     if ( $arg =~ /^\-/ ) {
  32         if  ( $arg =~ /^\-([abdin])$/ ) {
  33             $output = $1;
  34         } else {
  35             die "$0: Unknown option: ${arg}\n";
  36         }
  37     } else {
  38         push (@args, $arg);
  39     }
  40 }
  41
  42 $fname = "insns.dat" unless $fname = $args[0];
  43 open (F, $fname) || die "unable to open $fname";
  44
  45 %dinstables = ();
  46 @bytecode_list = ();
  47
  48 $line = 0;
  49 $insns = 0;
  50 while (<F>) {
  51   $line++;
  52   chomp;
  53   next if ( /^\s*(\;.*|)$/ );   # comments or blank lines
  54
  55   unless (/^\s*(\S+)\s+(\S+)\s+(\S+|\[.*\])\s+(\S+)\s*$/) {
  56       warn "line $line does not contain four fields\n";
  57       next;
  58   }
  59   @fields = ($1, $2, $3, $4);
  60   ($formatted, $nd) = format_insn(@fields);
  61   if ($formatted) {
  62     $insns++;
  63     $aname = "aa_$fields[0]";
  64     push @$aname, $formatted;
  65   }
  66   if ( $fields[0] =~ /cc$/ ) {
  67       # Conditional instruction
  68       $k_opcodes_cc{$fields[0]}++;
  69   } else {
  70       # Unconditional instruction
  71       $k_opcodes{$fields[0]}++;
  72   }
  73   if ($formatted && !$nd) {
  74     push @big, $formatted;
  75     my @sseq = startseq($fields[2]);
  76     foreach $i (@sseq) {
  77         if (!defined($dinstables{$i})) {
  78             $dinstables{$i} = [];
  79         }
  80         push(@{$dinstables{$i}}, $#big);
  81     }
  82   }
  83 }
  84
  85 close F;
  86
  87 #
  88 # Generate the bytecode array.  At this point, @bytecode_list contains
  89 # the full set of bytecodes.
  90 #
  91
  92 # Sort by descending length
  93 @bytecode_list = sort { scalar(@$b) <=> scalar(@$a) } @bytecode_list;
  94 @bytecode_array = ();
  95 %bytecode_pos = ();
  96 $bytecode_next = 0;
  97 foreach $bl (@bytecode_list) {
  98     my $h = hexstr(@$bl);
  99     next if (defined($bytecode_pos{$h}));
 100
 101     push(@bytecode_array, $bl);
 102     while ($h ne '') {
 103         $bytecode_pos{$h} = $bytecode_next;
 104         $h = substr($h, 2);
 105         $bytecode_next++;
 106     }
 107 }
 108 undef @bytecode_list;
 109
 110 @opcodes    = sort keys(%k_opcodes);
 111 @opcodes_cc = sort keys(%k_opcodes_cc);
 112
 113 if ( !defined($output) || $output eq 'b') {
 114     print STDERR "Writing insnsb.c...\n";
 115
 116     open B, ">insnsb.c";
 117
 118     print B "/* This file auto-generated from insns.dat by insns.pl" .
 119         " - don't edit it */\n\n";
 120
 121     print B "#include \"nasm.h\"\n";
 122     print B "#include \"insns.h\"\n\n";
 123
 124     print B "const uint8_t nasm_bytecodes[$bytecode_next] = {\n";
 125
 126     $p = 0;
 127     foreach $bl (@bytecode_array) {
 128         printf B "    /* %5d */ ", $p;
 129         foreach $d (@$bl) {
 130             printf B "%#o,", $d;
 131             $p++;
 132         }
 133         printf B "\n";
 134     }
 135     print B "};\n";
 136
 137     close B;
 138 }
 139
 140 if ( !defined($output) || $output eq 'a' ) {
 141     print STDERR "Writing insnsa.c...\n";
 142
 143     open A, ">insnsa.c";
 144
 145     print A "/* This file auto-generated from insns.dat by insns.pl" .
 146         " - don't edit it */\n\n";
 147
 148     print A "#include \"nasm.h\"\n";
 149     print A "#include \"insns.h\"\n\n";
 150
 151     foreach $i (@opcodes, @opcodes_cc) {
 152         print A "static const struct itemplate instrux_${i}[] = {\n";
 153         $aname = "aa_$i";
 154         foreach $j (@$aname) {
 155             print A "    ", codesubst($j), "\n";
 156         }
 157         print A "    ITEMPLATE_END\n};\n\n";
 158     }
 159     print A "const struct itemplate * const nasm_instructions[] = {\n";
 160     foreach $i (@opcodes, @opcodes_cc) {
 161         print A "    instrux_${i},\n";
 162     }
 163     print A "};\n";
 164
 165     close A;
 166 }
 167
 168 if ( !defined($output) || $output eq 'd' ) {
 169     print STDERR "Writing insnsd.c...\n";
 170
 171     open D, ">insnsd.c";
 172
 173     print D "/* This file auto-generated from insns.dat by insns.pl" .
 174         " - don't edit it */\n\n";
 175
 176     print D "#include \"nasm.h\"\n";
 177     print D "#include \"insns.h\"\n\n";
 178
 179     print D "static const struct itemplate instrux[] = {\n";
 180     $n = 0;
 181     foreach $j (@big) {
 182         printf D "    /* %4d */ %s\n", $n++, codesubst($j);
 183     }
 184     print D "};\n";
 185
 186     foreach $h (sort(keys(%dinstables))) {
 187         next if ($h eq '');     # Skip pseudo-instructions
 188         print D "\nstatic const struct itemplate * const itable_${h}[] = {\n";
 189         foreach $j (@{$dinstables{$h}}) {
 190             print D "    instrux + $j,\n";
 191         }
 192         print D "};\n";
 193     }
 194
 195     @prefix_list = ();
 196     foreach $h (@disasm_prefixes, '') {
 197         for ($c = 0; $c < 256; $c++) {
 198             $nn = sprintf("%s%02X", $h, $c);
 199             if ($is_prefix{$nn} || defined($dinstables{$nn})) {
 200                 # At least one entry in this prefix table
 201                 push(@prefix_list, $h);
 202                 $is_prefix{$h} = 1;
 203                 last;
 204             }
 205         }
 206     }
 207
 208     foreach $h (@prefix_list) {
 209         print D "\n";
 210         print D "static " unless ($h eq '');
 211         print D "const struct disasm_index ";
 212         print D ($h eq '') ? 'itable' : "itable_$h";
 213         print D "[256] = {\n";
 214         for ($c = 0; $c < 256; $c++) {
 215             $nn = sprintf("%s%02X", $h, $c);
 216             if ($is_prefix{$nn}) {
 217                 die "$fname: ambiguous decoding of $nn\n"
 218                     if (defined($dinstables{$nn}));
 219                 printf D "    { itable_%s, -1 },\n", $nn;
 220             } elsif (defined($dinstables{$nn})) {
 221                 printf D "    { itable_%s, %u },\n",
 222                 $nn, scalar(@{$dinstables{$nn}});
 223             } else {
 224                 printf D "    { NULL, 0 },\n";
 225             }
 226         }
 227         print D "};\n";
 228     }
 229
 230     print D "\nconst struct disasm_index * const itable_VEX[32][8] = {\n   ";
 231     for ($m = 0; $m < 32; $m++) {
 232         print D " {\n";
 233         for ($lp = 0; $lp < 8; $lp++) {
 234             $vp = sprintf("VEX%02X%01X", $m, $lp);
 235             if ($is_prefix{$vp}) {
 236                 printf D "        itable_%s,\n", $vp;
 237             } else {
 238                 print  D "        NULL,\n";
 239             }
 240         }
 241         print D "    },";
 242     }
 243     print D "\n};\n";
 244
 245     close D;
 246 }
 247
 248 if ( !defined($output) || $output eq 'i' ) {
 249     print STDERR "Writing insnsi.h...\n";
 250
 251     open I, ">insnsi.h";
 252
 253     print I "/* This file is auto-generated from insns.dat by insns.pl" .
 254         " - don't edit it */\n\n";
 255     print I "/* This file in included by nasm.h */\n\n";
 256
 257     print I "/* Instruction names */\n\n";
 258     print I "#ifndef NASM_INSNSI_H\n";
 259     print I "#define NASM_INSNSI_H 1\n\n";
 260     print I "enum opcode {\n";
 261     $maxlen = 0;
 262     foreach $i (@opcodes, @opcodes_cc) {
 263         print I "\tI_${i},\n";
 264         $len = length($i);
 265         $len++ if ( $i =~ /cc$/ );      # Condition codes can be 3 characters long
 266         $maxlen = $len if ( $len > $maxlen );
 267     }
 268     print I "\tI_none = -1\n";
 269     print I "\n};\n\n";
 270     print I "#define MAX_INSLEN ", $maxlen, "\n";
 271     print I "#define FIRST_COND_OPCODE I_", $opcodes_cc[0], "\n\n";
 272     print I "#endif /* NASM_INSNSI_H */\n";
 273
 274     close I;
 275 }
 276
 277 if ( !defined($output) || $output eq 'n' ) {
 278     print STDERR "Writing insnsn.c...\n";
 279
 280     open N, ">insnsn.c";
 281
 282     print N "/* This file is auto-generated from insns.dat by insns.pl" .
 283         " - don't edit it */\n\n";
 284     print N "#include \"tables.h\"\n\n";
 285
 286     print N "const char * const nasm_insn_names[] = {";
 287     $first = 1;
 288     foreach $i (@opcodes, @opcodes_cc) {
 289         print N "," if ( !$first );
 290         $first = 0;
 291         $ilower = $i;
 292         $ilower =~ s/cc$//;     # Remove conditional cc suffix
 293         $ilower =~ tr/A-Z/a-z/; # Change to lower case (Perl 4 compatible)
 294         print N "\n\t\"${ilower}\"";
 295     }
 296     print N "\n};\n";
 297     close N;
 298 }
 299
 300 printf STDERR "Done: %d instructions\n", $insns;
 301
 302 sub format_insn(@) {
 303     my ($opcode, $operands, $codes, $flags) = @_;
 304     my $num, $nd = 0;
 305     my @bytecode;
 306
 307     return (undef, undef) if $operands eq "ignore";
 308
 309     # format the operands
 310     $operands =~ s/:/|colon,/g;
 311     $operands =~ s/mem(\d+)/mem|bits$1/g;
 312     $operands =~ s/mem/memory/g;
 313     $operands =~ s/memory_offs/mem_offs/g;
 314     $operands =~ s/imm(\d+)/imm|bits$1/g;
 315     $operands =~ s/imm/immediate/g;
 316     $operands =~ s/rm(\d+)/rm_gpr|bits$1/g;
 317     $operands =~ s/(mmx|xmm|ymm)rm/rm_$1/g;
 318     $operands =~ s/\=([0-9]+)/same_as|$1/g;
 319     if ($operands eq 'void') {
 320         @ops = ();
 321     } else {
 322         @ops = split(/\,/, $operands);
 323     }
 324     $num = scalar(@ops);
 325     while (scalar(@ops) < $MAX_OPERANDS) {
 326         push(@ops, '0');
 327     }
 328     $operands = join(',', @ops);
 329     $operands =~ tr/a-z/A-Z/;
 330
 331     # format the flags
 332     $flags =~ s/,/|IF_/g;
 333     $flags =~ s/(\|IF_ND|IF_ND\|)//, $nd = 1 if $flags =~ /IF_ND/;
 334     $flags = "IF_" . $flags;
 335
 336     @bytecode = (decodify($codes), 0);
 337     push(@bytecode_list, [@bytecode]);
 338     $codes = hexstr(@bytecode);
 339
 340     ("{I_$opcode, $num, {$operands}, \@\@CODES-$codes\@\@, $flags},", $nd);
 341 }
 342
 343 #
 344 # Look for @@CODES-xxx@@ sequences and replace them with the appropriate
 345 # offset into nasm_bytecodes
 346 #
 347 sub codesubst($) {
 348     my($s) = @_;
 349     my $n;
 350
 351     while ($s =~ /\@\@CODES-([0-9A-F]+)\@\@/) {
 352         my $pos = $bytecode_pos{$1};
 353         if (!defined($pos)) {
 354             die "$fname: no position assigned to byte code $1\n";
 355         }
 356         $s = $` . "nasm_bytecodes+${pos}" . "$'";
 357     }
 358     return $s;
 359 }
 360
 361 sub addprefix ($@) {
 362     my ($prefix, @list) = @_;
 363     my $x;
 364     my @l = ();
 365
 366     foreach $x (@list) {
 367         push(@l, sprintf("%s%02X", $prefix, $x));
 368     }
 369
 370     return @l;
 371 }
 372
 373 #
 374 # Turn a code string into a sequence of bytes
 375 #
 376 sub decodify($) {
 377   # Although these are C-syntax strings, by convention they should have
 378   # only octal escapes (for directives) and hexadecimal escapes
 379   # (for verbatim bytes)
 380     my($codestr) = @_;
 381
 382     if ($codestr =~ /^\s*\[([^\]]*)\]\s*$/) {
 383         return byte_code_compile($1);
 384     }
 385
 386     my $c = $codestr;
 387     my @codes = ();
 388
 389     while ($c ne '') {
 390         if ($c =~ /^\\x([0-9a-f]+)(.*)$/i) {
 391             push(@codes, hex $1);
 392             $c = $2;
 393             next;
 394         } elsif ($c =~ /^\\([0-7]{1,3})(.*)$/) {
 395             push(@codes, oct $1);
 396             $c = $2;
 397             next;
 398         } else {
 399             die "$fname: unknown code format in \"$codestr\"\n";
 400         }
 401     }
 402
 403     return @codes;
 404 }
 405
 406 # Turn a numeric list into a hex string
 407 sub hexstr(@) {
 408     my $s = '';
 409     my $c;
 410
 411     foreach $c (@_) {
 412         $s .= sprintf("%02X", $c);
 413     }
 414     return $s;
 415 }
 416
 417 # Here we determine the range of possible starting bytes for a given
 418 # instruction. We need only consider the codes:
 419 # \1 \2 \3     mean literal bytes, of course
 420 # \4 \5 \6 \7  mean PUSH/POP of segment registers: special case
 421 # \1[0123]     mean byte plus register value
 422 # \330         means byte plus condition code
 423 # \0 or \340   mean give up and return empty set
 424 # \17[234]     skip is4 control byte
 425 # \26x \270    skip VEX control bytes
 426 sub startseq($) {
 427   my ($codestr) = @_;
 428   my $word, @range;
 429   my @codes = ();
 430   my $c = $codestr;
 431   my $c0, $c1, $i;
 432   my $prefix = '';
 433
 434   @codes = decodify($codestr);
 435
 436   while ($c0 = shift(@codes)) {
 437       $c1 = $codes[0];
 438       if ($c0 == 01 || $c0 == 02 || $c0 == 03) {
 439           # Fixed byte string
 440           my $fbs = $prefix;
 441           while (1) {
 442               if ($c0 == 01 || $c0 == 02 || $c0 == 03) {
 443                   while ($c0--) {
 444                       $fbs .= sprintf("%02X", shift(@codes));
 445                   }
 446               } else {
 447                   last;
 448               }
 449               $c0 = shift(@codes);
 450           }
 451
 452           foreach $pfx (@disasm_prefixes) {
 453               if (substr($fbs, 0, length($pfx)) eq $pfx) {
 454                   $prefix = $pfx;
 455                   $fbs = substr($fbs, length($pfx));
 456                   last;
 457               }
 458           }
 459
 460           if ($fbs ne '') {
 461               return ($prefix.substr($fbs,0,2));
 462           }
 463
 464           unshift(@codes, $c0);
 465       } elsif ($c0 == 04) {
 466           return addprefix($prefix, 0x07, 0x17, 0x1F);
 467       } elsif ($c0 == 05) {
 468           return addprefix($prefix, 0xA1, 0xA9);
 469       } elsif ($c0 == 06) {
 470           return addprefix($prefix, 0x06, 0x0E, 0x16, 0x1E);
 471       } elsif ($c0 == 07) {
 472           return addprefix($prefix, 0xA0, 0xA8);
 473       } elsif ($c0 >= 010 && $c0 <= 013) {
 474           return addprefix($prefix, $c1..($c1+7));
 475       } elsif (($c0 & ~013) == 0144) {
 476           return addprefix($prefix, $c1, $c1|2);
 477       } elsif ($c0 == 0330) {
 478           return addprefix($prefix, $c1..($c1+15));
 479       } elsif ($c0 == 0 || $c0 == 0340) {
 480           return $prefix;
 481       } elsif (($c0 & ~3) == 0260 || $c0 == 0270) {
 482           my $m,$wlp,$vxp;
 483           $m   = shift(@codes);
 484           $wlp = shift(@codes);
 485           $prefix .= sprintf('VEX%02X%01X', $m, $wlp & 7);
 486       } elsif ($c0 >= 0172 && $c0 <= 174) {
 487           shift(@codes);        # Skip is4 control byte
 488       } else {
 489           # We really need to be able to distinguish "forbidden"
 490           # and "ignorable" codes here
 491       }
 492   }
 493   return $prefix;
 494 }
 495
 496 #
 497 # This function takes a series of byte codes in a format which is more
 498 # typical of the Intel documentation, and encode it.
 499 #
 500 # The format looks like:
 501 #
 502 # [operands: opcodes]
 503 #
 504 # The operands word lists the order of the operands:
 505 #
 506 # r = register field in the modr/m
 507 # m = modr/m
 508 # v = VEX "v" field
 509 # d = DREX "dst" field
 510 # i = immediate
 511 # s = register field of is4/imz2 field
 512 # - = implicit (unencoded) operand
 513 #
 514 # For an operand that should be filled into more than one field,
 515 # enter it as e.g. "r+v".
 516 #
 517 sub byte_code_compile($) {
 518     my($str) = @_;
 519     my $opr;
 520     my $opc;
 521     my @codes = ();
 522     my $litix = undef;
 523     my %oppos = ();
 524     my $i;
 525     my $op, $oq;
 526
 527     unless ($str =~ /^(([^\s:]*)\:|)\s*(.*\S)\s*$/) {
 528         die "$fname: $line: cannot parse: [$str]\n";
 529     }
 530     $opr = "\L$2";
 531     $opc = "\L$3";
 532
 533     my $op = 0;
 534     for ($i = 0; $i < length($opr); $i++) {
 535         my $c = substr($opr,$i,1);
 536         if ($c eq '+') {
 537             $op--;
 538         } else {
 539             $oppos{$c} = $op++;
 540         }
 541     }
 542
 543     $prefix_ok = 1;
 544     foreach $op (split(/\s*(?:\s|(?=[\/\\]))/, $opc)) {
 545         if ($op eq 'o16') {
 546             push(@codes, 0320);
 547         } elsif ($op eq 'o32') {
 548             push(@codes, 0321);
 549         } elsif ($op eq 'o64') {  # 64-bit operand size requiring REX.W
 550             push(@codes, 0324);
 551         } elsif ($op eq 'o64nw') { # Implied 64-bit operand size (no REX.W)
 552             push(@codes, 0323);
 553         } elsif ($op eq 'a16') {
 554             push(@codes, 0310);
 555         } elsif ($op eq 'a32') {
 556             push(@codes, 0311);
 557         } elsif ($op eq 'a64') {
 558             push(@codes, 0313);
 559         } elsif ($op eq '!osp') {
 560             push(@codes, 0364);
 561         } elsif ($op eq '!asp') {
 562             push(@codes, 0365);
 563         } elsif ($op eq 'rex.l') {
 564             push(@codes, 0334);
 565         } elsif ($op eq 'repe') {
 566             push(@codes, 0335);
 567         } elsif ($prefix_ok && $op =~ /^(66|f2|f3|np)$/) {
 568             # 66/F2/F3 prefix used as an opcode extension, or np = no prefix
 569             if ($op eq '66') {
 570                 push(@codes, 0361);
 571             } elsif ($op eq 'f2') {
 572                 push(@codes, 0362);
 573             } elsif ($op eq 'f3') {
 574                 push(@codes, 0363);
 575             } else {
 576                 push(@codes, 0360);
 577             }
 578         } elsif ($op =~ /^[0-9a-f]{2}$/) {
 579             if (defined($litix) && $litix+$codes[$litix]+1 == scalar @codes) {
 580                 $codes[$litix]++;
 581                 push(@codes, hex $op);
 582             } else {
 583                 $litix = scalar(@codes);
 584                 push(@codes, 01, hex $op);
 585             }
 586             $prefix_ok = 0;
 587         } elsif ($op eq '/r') {
 588             if (!defined($oppos{'r'}) || !defined($oppos{'m'})) {
 589                 die "$fname: $line: $op requires r and m operands\n";
 590             }
 591             push(@codes, 0100 + ($oppos{'m'} << 3) + $oppos{'r'});
 592             $prefix_ok = 0;
 593         } elsif ($op =~ m:^/([0-7])$:) {
 594             if (!defined($oppos{'m'})) {
 595                 die "$fname: $line: $op requires m operand\n";
 596             }
 597             push(@codes, 0200 + ($oppos{'m'} << 3) + $1);
 598             $prefix_ok = 0;
 599         } elsif ($op =~ /^vex(|\..*)$/) {
 600             my ($m,$w,$l,$p) = (undef,2,undef,0);
 601             my $has_nds = 0;
 602             foreach $oq (split(/\./, $op)) {
 603                 if ($oq eq 'vex') {
 604                     # prefix
 605                 } elsif ($oq eq '128' || $oq eq 'l0') {
 606                     $l = 0;
 607                 } elsif ($oq eq '256' || $oq eq 'l1') {
 608                     $l = 1;
 609                 } elsif ($oq eq 'w0') {
 610                     $w = 0;
 611                 } elsif ($oq eq 'w1') {
 612                     $w = 1;
 613                 } elsif ($oq eq 'wx') {
 614                     $w = 2;
 615                 } elsif ($oq eq 'ww') {
 616                     $w = 3;
 617                 } elsif ($oq eq '66') {
 618                     $p = 1;
 619                 } elsif ($oq eq 'f3') {
 620                     $p = 2;
 621                 } elsif ($oq eq 'f2') {
 622                     $p = 3;
 623                 } elsif ($oq eq '0f') {
 624                     $m = 1;
 625                 } elsif ($oq eq '0f38') {
 626                     $m = 2;
 627                 } elsif ($oq eq '0f3a') {
 628                     $m = 3;
 629                 } elsif ($oq =~ /^m([0-9]+)$/) {
 630                     $m = $1+0;
 631                 } elsif ($oq eq 'nds' || $oq eq 'ndd') {
 632                     if (!defined($oppos{'v'})) {
 633                         die "$fname: $line: vex.$oq without 'v' operand\n";
 634                     }
 635                     $has_nds = 1;
 636                 } else {
 637                     die "$fname: $line: undefined VEX subcode: $oq\n";
 638                 }
 639             }
 640             if (!defined($m) || !defined($w) || !defined($l) || !defined($p)) {
 641                 die "$fname: $line: missing fields in VEX specification\n";
 642             }
 643             if (defined($oppos{'v'}) && !$has_nds) {
 644                 die "$fname: $line: 'v' operand without vex.nds or vex.ndd\n";
 645             }
 646             push(@codes, defined($oppos{'v'}) ? 0260+$oppos{'v'} : 0270,
 647                  $m, ($w << 3)+($l << 2)+$p);
 648             $prefix_ok = 0;
 649         } elsif ($op =~ /^\/drex([01])$/) {
 650             my $oc0 = $1;
 651             if (!defined($oppos{'d'})) {
 652                 die "$fname: $line: DREX without a 'd' operand\n";
 653             }
 654             # Note the use of *unshift* here, as opposed to *push*.
 655             # This is because NASM want this byte code at the start of
 656             # the instruction sequence, but the AMD documentation puts
 657             # this at (roughly) the position of the drex byte itself.
 658             # This allows us to match the AMD documentation and still
 659             # do the right thing.
 660             unshift(@codes, 0160+$oppos{'d'}+($oc0 ? 4 : 0));
 661         } elsif ($op =~ /^(ib\,s|ib|ib\,w|iw|iwd|id|iwdq|rel|rel8|rel16|rel32|iq|seg|ibw|ibd|ibd,s)$/) {
 662             if (!defined($oppos{'i'})) {
 663                 die "$fname: $line: $op without 'i' operand\n";
 664             }
 665             if ($op eq 'ib,s') { # Signed imm8
 666                 push(@codes, 014+$oppos{'i'});
 667             } elsif ($op eq 'ib') { # imm8
 668                 push(@codes, 020+$oppos{'i'});
 669             } elsif ($op eq 'ib,u') { # Unsigned imm8
 670                 push(@codes, 024+$oppos{'i'});
 671             } elsif ($op eq 'iw') { # imm16
 672                 push(@codes, 030+$oppos{'i'});
 673             } elsif ($op eq 'iwd') { # imm16 or imm32, depending on opsize
 674                 push(@codes, 034+$oppos{'i'});
 675             } elsif ($op eq 'id') { # imm32
 676                 push(@codes, 040+$oppos{'i'});
 677             } elsif ($op eq 'iwdq') { # imm16/32/64, depending on opsize
 678                 push(@codes, 044+$oppos{'i'});
 679             } elsif ($op eq 'rel8') {
 680                 push(@codes, 050+$oppos{'i'});
 681             } elsif ($op eq 'iq') {
 682                 push(@codes, 054+$oppos{'i'});
 683             } elsif ($op eq 'rel16') {
 684                 push(@codes, 060+$oppos{'i'});
 685             } elsif ($op eq 'rel') { # 16 or 32 bit relative operand
 686                 push(@codes, 064+$oppos{'i'});
 687             } elsif ($op eq 'rel32') {
 688                 push(@codes, 070+$oppos{'i'});
 689             } elsif ($op eq 'seg') {
 690                 push(@codes, 074+$oppos{'i'});
 691             } elsif ($op eq 'ibw') { # imm16 that can be bytified
 692                 if (!defined($s_pos)) {
 693                     die "$fname: $line: $op without a +s byte\n";
 694                 }
 695                 $codes[$s_pos] += 0144;
 696                 push(@codes, 0140+$oppos{'i'});
 697             } elsif ($op eq 'ibd') { # imm32 that can be bytified
 698                 if (!defined($s_pos)) {
 699                     die "$fname: $line: $op without a +s byte\n";
 700                 }
 701                 $codes[$s_pos] += 0154;
 702                 push(@codes, 0150+$oppos{'i'});
 703             } elsif ($op eq 'ibd,s') {
 704                 # imm32 that can be bytified, sign extended to 64 bits
 705                 if (!defined($s_pos)) {
 706                     die "$fname: $line: $op without a +s byte\n";
 707                 }
 708                 $codes[$s_pos] += 0154;
 709                 push(@codes, 0250+$oppos{'i'});
 710             }
 711             $prefix_ok = 0;
 712         } elsif ($op eq '/is4') {
 713             if (!defined($oppos{'s'})) {
 714                 die "$fname: $line: $op without 's' operand\n";
 715             }
 716             if (defined($oppos{'i'})) {
 717                 push(@codes, 0172, ($oppos{'s'} << 3)+$oppos{'i'});
 718             } else {
 719                 push(@codes, 0174, $oppos{'s'});
 720             }
 721             $prefix_ok = 0;
 722         } elsif ($op =~ /^\/is4\=([0-9]+)$/) {
 723             my $imm = $1;
 724             if (!defined($oppos{'s'})) {
 725                 die "$fname: $line: $op without 's' operand\n";
 726             }
 727             if ($imm < 0 || $imm > 15) {
 728                 die "$fname: $line: invalid imm4 value for $op: $imm\n";
 729             }
 730             push(@codes, 0173, ($oppos{'s'} << 4) + $imm);
 731             $prefix_ok = 0;
 732         } elsif ($op =~ /^([0-9a-f]{2})\+s$/) {
 733             if (!defined($oppos{'i'})) {
 734                 die "$fname: $line: $op without 'i' operand\n";
 735             }
 736             $s_pos = scalar @codes;
 737             push(@codes, $oppos{'i'}, hex $1);
 738             $prefix_ok = 0;
 739         } elsif ($op =~ /^([0-9a-f]{2})\+c$/) {
 740             push(@codes, 0330, hex $1);
 741             $prefix_ok = 0;
 742         } elsif ($op =~ /^\\([0-7]+|x[0-9a-f]{2})$/) {
 743             # Escape to enter literal bytecodes
 744             push(@codes, oct $1);
 745         } else {
 746             die "$fname: $line: unknown operation: $op\n";
 747         }
 748     }
 749
 750     return @codes;
 751 }