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 $h (sort(keys(%dinstables))) {
 187         print D "\nstatic const struct itemplate * const itable_${h}[] = {\n";
 188         foreach $j (@{$dinstables{$h}}) {
 189             print D "    instrux + $j,\n";
 190         }
 191         print D "};\n";
 192     }
 193
 194     @prefix_list = ();
 195     foreach $h (@disasm_prefixes, '') {
 196         for ($c = 0; $c < 256; $c++) {
 197             $nn = sprintf("%s%02X", $h, $c);
 198             if ($is_prefix{$nn} || defined($dinstables{$nn})) {
 199                 # At least one entry in this prefix table
 200                 push(@prefix_list, $h);
 201                 $is_prefix{$h} = 1;
 202                 last;
 203             }
 204         }
 205     }
 206
 207     foreach $h (@prefix_list) {
 208         print D "\n";
 209         print D "static " unless ($h eq '');
 210         print D "const struct disasm_index ";
 211         print D ($h eq '') ? 'itable' : "itable_$h";
 212         print D "[256] = {\n";
 213         for ($c = 0; $c < 256; $c++) {
 214             $nn = sprintf("%s%02X", $h, $c);
 215             if ($is_prefix{$nn}) {
 216                 die "$0: ambiguous decoding of $nn\n"
 217                     if (defined($dinstables{$nn}));
 218                 printf D "    { itable_%s, -1 },\n", $nn;
 219             } elsif (defined($dinstables{$nn})) {
 220                 printf D "    { itable_%s, %u },\n",
 221                 $nn, scalar(@{$dinstables{$nn}});
 222             } else {
 223                 printf D "    { NULL, 0 },\n";
 224             }
 225         }
 226         print D "};\n";
 227     }
 228
 229     print D "\nconst struct disasm_index * const itable_VEX[32][8] = {\n   ";
 230     for ($m = 0; $m < 32; $m++) {
 231         print D " {\n";
 232         for ($lp = 0; $lp < 8; $lp++) {
 233             $vp = sprintf("VEX%02X%01X", $m, $lp);
 234             if ($is_prefix{$vp}) {
 235                 printf D "        itable_%s,\n", $vp;
 236             } else {
 237                 print  D "        NULL,\n";
 238             }
 239         }
 240         print D "    },";
 241     }
 242     print D "\n};\n";
 243
 244     close D;
 245 }
 246
 247 if ( !defined($output) || $output eq 'i' ) {
 248     print STDERR "Writing insnsi.h...\n";
 249
 250     open I, ">insnsi.h";
 251
 252     print I "/* This file is auto-generated from insns.dat by insns.pl" .
 253         " - don't edit it */\n\n";
 254     print I "/* This file in included by nasm.h */\n\n";
 255
 256     print I "/* Instruction names */\n\n";
 257     print I "#ifndef NASM_INSNSI_H\n";
 258     print I "#define NASM_INSNSI_H 1\n\n";
 259     print I "enum opcode {\n";
 260     $maxlen = 0;
 261     foreach $i (@opcodes, @opcodes_cc) {
 262         print I "\tI_${i},\n";
 263         $len = length($i);
 264         $len++ if ( $i =~ /cc$/ );      # Condition codes can be 3 characters long
 265         $maxlen = $len if ( $len > $maxlen );
 266     }
 267     print I "\tI_none = -1\n";
 268     print I "\n};\n\n";
 269     print I "#define MAX_INSLEN ", $maxlen, "\n";
 270     print I "#define FIRST_COND_OPCODE I_", $opcodes_cc[0], "\n\n";
 271     print I "#endif /* NASM_INSNSI_H */\n";
 272
 273     close I;
 274 }
 275
 276 if ( !defined($output) || $output eq 'n' ) {
 277     print STDERR "Writing insnsn.c...\n";
 278
 279     open N, ">insnsn.c";
 280
 281     print N "/* This file is auto-generated from insns.dat by insns.pl" .
 282         " - don't edit it */\n\n";
 283     print N "#include \"tables.h\"\n\n";
 284
 285     print N "const char * const nasm_insn_names[] = {";
 286     $first = 1;
 287     foreach $i (@opcodes) {
 288         print N "," if ( !$first );
 289         $first = 0;
 290         $ilower = $i;
 291         $ilower =~ tr/A-Z/a-z/; # Change to lower case (Perl 4 compatible)
 292         print N "\n\t\"${ilower}\"";
 293     }
 294     print N "\n};\n\n";
 295     print N "/* Conditional instructions */\n";
 296     print N "const char * const nasm_cond_insn_names[] = {";
 297     $first = 1;
 298     foreach $i (@opcodes_cc) {
 299         print N "," if ( !$first );
 300         $first = 0;
 301         $ilower = $i;
 302         $ilower =~ s/cc$//;             # Skip cc suffix
 303         $ilower =~ tr/A-Z/a-z/; # Change to lower case (Perl 4 compatible)
 304         print N "\n\t\"${ilower}\"";
 305     }
 306
 307     print N "\n};\n\n";
 308     print N "/* and the corresponding opcodes */\n";
 309     print N "const enum opcode nasm_cond_insn_opcodes[] = {";
 310     $first = 1;
 311     foreach $i (@opcodes_cc) {
 312         print N "," if ( !$first );
 313         $first = 0;
 314         print N "\n\tI_$i";
 315     }
 316
 317     print N "\n};\n";
 318     close N;
 319 }
 320
 321 printf STDERR "Done: %d instructions\n", $insns;
 322
 323 sub format_insn(@) {
 324     my ($opcode, $operands, $codes, $flags) = @_;
 325     my $num, $nd = 0;
 326     my @bytecode;
 327
 328     return (undef, undef) if $operands eq "ignore";
 329
 330     # format the operands
 331     $operands =~ s/:/|colon,/g;
 332     $operands =~ s/mem(\d+)/mem|bits$1/g;
 333     $operands =~ s/mem/memory/g;
 334     $operands =~ s/memory_offs/mem_offs/g;
 335     $operands =~ s/imm(\d+)/imm|bits$1/g;
 336     $operands =~ s/imm/immediate/g;
 337     $operands =~ s/rm(\d+)/rm_gpr|bits$1/g;
 338     $operands =~ s/(mmx|xmm|ymm)rm/rm_$1/g;
 339     $operands =~ s/\=([0-9]+)/same_as|$1/g;
 340     if ($operands eq 'void') {
 341         @ops = ();
 342     } else {
 343         @ops = split(/\,/, $operands);
 344     }
 345     $num = scalar(@ops);
 346     while (scalar(@ops) < $MAX_OPERANDS) {
 347         push(@ops, '0');
 348     }
 349     $operands = join(',', @ops);
 350     $operands =~ tr/a-z/A-Z/;
 351
 352     # format the flags
 353     $flags =~ s/,/|IF_/g;
 354     $flags =~ s/(\|IF_ND|IF_ND\|)//, $nd = 1 if $flags =~ /IF_ND/;
 355     $flags = "IF_" . $flags;
 356
 357     @bytecode = (decodify($codes), 0);
 358     push(@bytecode_list, [@bytecode]);
 359     $codes = hexstr(@bytecode);
 360
 361     ("{I_$opcode, $num, {$operands}, \@\@CODES-$codes\@\@, $flags},", $nd);
 362 }
 363
 364 #
 365 # Look for @@CODES-xxx@@ sequences and replace them with the appropriate
 366 # offset into nasm_bytecodes
 367 #
 368 sub codesubst($) {
 369     my($s) = @_;
 370     my $n;
 371
 372     while ($s =~ /\@\@CODES-([0-9A-F]+)\@\@/) {
 373         my $pos = $bytecode_pos{$1};
 374         if (!defined($pos)) {
 375             die "$0: no position assigned to byte code $1\n";
 376         }
 377         $s = $` . "nasm_bytecodes+${pos}" . "$'";
 378     }
 379     return $s;
 380 }
 381
 382 sub addprefix ($@) {
 383     my ($prefix, @list) = @_;
 384     my $x;
 385     my @l = ();
 386
 387     foreach $x (@list) {
 388         push(@l, sprintf("%s%02X", $prefix, $x));
 389     }
 390
 391     return @l;
 392 }
 393
 394 #
 395 # Turn a code string into a sequence of bytes
 396 #
 397 sub decodify($) {
 398   # Although these are C-syntax strings, by convention they should have
 399   # only octal escapes (for directives) and hexadecimal escapes
 400   # (for verbatim bytes)
 401     my($codestr) = @_;
 402
 403     if ($codestr =~ /^\s*\[([^\]]*)\]\s*$/) {
 404         return byte_code_compile($1);
 405     }
 406
 407     my $c = $codestr;
 408     my @codes = ();
 409
 410     while ($c ne '') {
 411         if ($c =~ /^\\x([0-9a-f]+)(.*)$/i) {
 412             push(@codes, hex $1);
 413             $c = $2;
 414             next;
 415         } elsif ($c =~ /^\\([0-7]{1,3})(.*)$/) {
 416             push(@codes, oct $1);
 417             $c = $2;
 418             next;
 419         } else {
 420             die "$0: unknown code format in \"$codestr\"\n";
 421         }
 422     }
 423
 424     return @codes;
 425 }
 426
 427 # Turn a numeric list into a hex string
 428 sub hexstr(@) {
 429     my $s = '';
 430     my $c;
 431
 432     foreach $c (@_) {
 433         $s .= sprintf("%02X", $c);
 434     }
 435     return $s;
 436 }
 437
 438 # Here we determine the range of possible starting bytes for a given
 439 # instruction. We need only consider the codes:
 440 # \1 \2 \3     mean literal bytes, of course
 441 # \4 \5 \6 \7  mean PUSH/POP of segment registers: special case
 442 # \1[0123]     mean byte plus register value
 443 # \330         means byte plus condition code
 444 # \0 or \340   mean give up and return empty set
 445 # \17[234]     skip is4 control byte
 446 # \26x \270    skip VEX control bytes
 447 sub startseq($) {
 448   my ($codestr) = @_;
 449   my $word, @range;
 450   my @codes = ();
 451   my $c = $codestr;
 452   my $c0, $c1, $i;
 453   my $prefix = '';
 454
 455   @codes = decodify($codestr);
 456
 457   while ($c0 = shift(@codes)) {
 458       $c1 = $codes[0];
 459       if ($c0 == 01 || $c0 == 02 || $c0 == 03) {
 460           # Fixed byte string
 461           my $fbs = $prefix;
 462           while (1) {
 463               if ($c0 == 01 || $c0 == 02 || $c0 == 03) {
 464                   while ($c0--) {
 465                       $fbs .= sprintf("%02X", shift(@codes));
 466                   }
 467               } else {
 468                   last;
 469               }
 470               $c0 = shift(@codes);
 471           }
 472
 473           foreach $pfx (@disasm_prefixes) {
 474               if (substr($fbs, 0, length($pfx)) eq $pfx) {
 475                   $prefix = $pfx;
 476                   $fbs = substr($fbs, length($pfx));
 477                   last;
 478               }
 479           }
 480
 481           if ($fbs ne '') {
 482               return ($prefix.substr($fbs,0,2));
 483           }
 484
 485           unshift(@codes, $c0);
 486       } elsif ($c0 == 04) {
 487           return addprefix($prefix, 0x07, 0x17, 0x1F);
 488       } elsif ($c0 == 05) {
 489           return addprefix($prefix, 0xA1, 0xA9);
 490       } elsif ($c0 == 06) {
 491           return addprefix($prefix, 0x06, 0x0E, 0x16, 0x1E);
 492       } elsif ($c0 == 07) {
 493           return addprefix($prefix, 0xA0, 0xA8);
 494       } elsif ($c0 >= 010 && $c0 <= 013) {
 495           return addprefix($prefix, $c1..($c1+7));
 496       } elsif (($c0 & ~013) == 0144) {
 497           return addprefix($prefix, $c1, $c1|2);
 498       } elsif ($c0 == 0330) {
 499           return addprefix($prefix, $c1..($c1+15));
 500       } elsif ($c0 == 0 || $c0 == 0340) {
 501           return $prefix;
 502       } elsif (($c0 & ~3) == 0260 || $c0 == 0270) {
 503           my $m,$wlp,$vxp;
 504           $m   = shift(@codes);
 505           $wlp = shift(@codes);
 506           $prefix .= sprintf('VEX%02X%01X', $m, $wlp & 7);
 507       } elsif ($c0 >= 0172 && $c0 <= 174) {
 508           shift(@codes);        # Skip is4 control byte
 509       } else {
 510           # We really need to be able to distinguish "forbidden"
 511           # and "ignorable" codes here
 512       }
 513   }
 514   return $prefix;
 515 }
 516
 517 #
 518 # This function takes a series of byte codes in a format which is more
 519 # typical of the Intel documentation, and encode it.
 520 #
 521 # The format looks like:
 522 #
 523 # [operands: opcodes]
 524 #
 525 # The operands word lists the order of the operands:
 526 #
 527 # r = register field in the modr/m
 528 # m = modr/m
 529 # v = VEX "v" field
 530 # d = DREX "dst" field
 531 # i = immediate
 532 # s = register field of is4/imz2 field
 533 # - = implicit (unencoded) operand
 534 #
 535 # For an operand that should be filled into more than one field,
 536 # enter it as e.g. "r+v".
 537 #
 538 sub byte_code_compile($) {
 539     my($str) = @_;
 540     my $opr;
 541     my $opc;
 542     my @codes = ();
 543     my $litix = undef;
 544     my %oppos = ();
 545     my $i;
 546     my $op, $oq;
 547
 548     if ($str =~ /^(\S*)\:\s*(.*\S)\s*$/) {
 549         $opr = "\L$1";
 550         $opc = "\L$2";
 551     } else {
 552         $opr = '';
 553         $opc = "\L$str";
 554     }
 555
 556     my $op = 0;
 557     for ($i = 0; $i < length($opr); $i++) {
 558         my $c = substr($opr,$i,1);
 559         if ($c eq '+') {
 560             $op--;
 561         } else {
 562             $oppos{$c} = $op++;
 563         }
 564     }
 565
 566     $prefix_ok = 1;
 567     foreach $op (split(/\s*(?:\s|(?=[\/\\]))/, $opc)) {
 568         if ($op eq 'o16') {
 569             push(@codes, 0320);
 570         } elsif ($op eq 'o32') {
 571             push(@codes, 0321);
 572         } elsif ($op eq 'o64') {  # 64-bit operand size requiring REX.W
 573             push(@codes, 0324);
 574         } elsif ($op eq 'o64nw') { # Implied 64-bit operand size (no REX.W)
 575             push(@codes, 0323);
 576         } elsif ($op eq 'a16') {
 577             push(@codes, 0310);
 578         } elsif ($op eq 'a32') {
 579             push(@codes, 0311);
 580         } elsif ($op eq 'a64') {
 581             push(@codes, 0313);
 582         } elsif ($op eq '!osp') {
 583             push(@codes, 0364);
 584         } elsif ($op eq '!asp') {
 585             push(@codes, 0365);
 586         } elsif ($op eq 'rex.l') {
 587             push(@codes, 0334);
 588         } elsif ($op eq 'repe') {
 589             push(@codes, 0335);
 590         } elsif ($prefix_ok && $op =~ /^(66|f2|f3|np)$/) {
 591             # 66/F2/F3 prefix used as an opcode extension, or np = no prefix
 592             if ($op eq '66') {
 593                 push(@codes, 0361);
 594             } elsif ($op eq 'f2') {
 595                 push(@codes, 0362);
 596             } elsif ($op eq 'f3') {
 597                 push(@codes, 0363);
 598             } else {
 599                 push(@codes, 0360);
 600             }
 601         } elsif ($op =~ /^[0-9a-f]{2}$/) {
 602             if (defined($litix) && $litix+$codes[$litix]+1 == scalar @codes) {
 603                 $codes[$litix]++;
 604                 push(@codes, hex $op);
 605             } else {
 606                 $litix = scalar(@codes);
 607                 push(@codes, 01, hex $op);
 608             }
 609             $prefix_ok = 0;
 610         } elsif ($op eq '/r') {
 611             if (!defined($oppos{'r'}) || !defined($oppos{'m'})) {
 612                 die "$0: $line: $op requires r and m operands\n";
 613             }
 614             push(@codes, 0100 + ($oppos{'m'} << 3) + $oppos{'r'});
 615             $prefix_ok = 0;
 616         } elsif ($op =~ m:^/([0-7])$:) {
 617             if (!defined($oppos{'m'})) {
 618                 die "$0: $line: $op requires m operand\n";
 619             }
 620             push(@codes, 0200 + ($oppos{'m'} << 3) + $1);
 621             $prefix_ok = 0;
 622         } elsif ($op =~ /^vex(|\..*)$/) {
 623             my ($m,$w,$l,$p) = (undef,2,undef,0);
 624             foreach $oq (split(/\./, $op)) {
 625                 if ($oq eq 'vex') {
 626                     # prefix
 627                 } elsif ($oq eq '128' || $oq eq 'l0') {
 628                     $l = 0;
 629                 } elsif ($oq eq '256' || $oq eq 'l1') {
 630                     $l = 1;
 631                 } elsif ($oq eq 'w0') {
 632                     $w = 0;
 633                 } elsif ($oq eq 'w1') {
 634                     $w = 1;
 635                 } elsif ($oq eq '66') {
 636                     $p = 1;
 637                 } elsif ($oq eq 'f3') {
 638                     $p = 2;
 639                 } elsif ($oq eq 'f2') {
 640                     $p = 3;
 641                 } elsif ($oq eq '0f') {
 642                     $m = 1;
 643                 } elsif ($oq eq '0f38') {
 644                     $m = 2;
 645                 } elsif ($oq eq '0f3a') {
 646                     $m = 3;
 647                 } elsif ($oq =~ /^m([0-9]+)$/) {
 648                     $m = $1+0;
 649                 } elsif ($oq eq 'nds' || $oq eq 'ndd') {
 650                     if (!defined($oppos{'v'})) {
 651                         die "$0: $line: vex.$oq without 'v' operand\n";
 652                     }
 653                 } else {
 654                     die "$0: $line: undefined VEX subcode: $oq\n";
 655                 }
 656             }
 657             if (!defined($m) || !defined($w) || !defined($l) || !defined($p)) {
 658                 die "$0: $line: missing fields in VEX specification\n";
 659             }
 660             push(@codes, defined($oppos{'v'}) ? 0260+$oppos{'v'} : 0270,
 661                  $m, ($w << 3)+($l << 2)+$p);
 662             $prefix_ok = 0;
 663         } elsif ($op =~ /^\/drex([01])$/) {
 664             my $oc0 = $1;
 665             if (!defined($oppos{'d'})) {
 666                 die "$0: $line: DREX without a 'd' operand\n";
 667             }
 668             # Note the use of *unshift* here, as opposed to *push*.
 669             # This is because NASM want this byte code at the start of
 670             # the instruction sequence, but the AMD documentation puts
 671             # this at (roughly) the position of the drex byte itself.
 672             # This allows us to match the AMD documentation and still
 673             # do the right thing.
 674             unshift(@codes, 0160+$oppos{'d'}+($oc0 ? 4 : 0));
 675         } elsif ($op =~ /^(ib\,s|ib|ib\,w|iw|iwd|id|iwdq|rel|rel8|rel16|rel32|iq|seg|ibw|ibd|ibd,s)$/) {
 676             if (!defined($oppos{'i'})) {
 677                 die "$0: $op without 'i' operand\n";
 678             }
 679             if ($op eq 'ib,s') { # Signed imm8
 680                 push(@codes, 014+$oppos{'i'});
 681             } elsif ($op eq 'ib') { # imm8
 682                 push(@codes, 020+$oppos{'i'});
 683             } elsif ($op eq 'ib,u') { # Unsigned imm8
 684                 push(@codes, 024+$oppos{'i'});
 685             } elsif ($op eq 'iw') { # imm16
 686                 push(@codes, 030+$oppos{'i'});
 687             } elsif ($op eq 'iwd') { # imm16 or imm32, depending on opsize
 688                 push(@codes, 034+$oppos{'i'});
 689             } elsif ($op eq 'id') { # imm32
 690                 push(@codes, 040+$oppos{'i'});
 691             } elsif ($op eq 'iwdq') { # imm16/32/64, depending on opsize
 692                 push(@codes, 044+$oppos{'i'});
 693             } elsif ($op eq 'rel8') {
 694                 push(@codes, 050+$oppos{'i'});
 695             } elsif ($op eq 'iq') {
 696                 push(@codes, 054+$oppos{'i'});
 697             } elsif ($op eq 'rel16') {
 698                 push(@codes, 060+$oppos{'i'});
 699             } elsif ($op eq 'rel') { # 16 or 32 bit relative operand
 700                 push(@codes, 064+$oppos{'i'});
 701             } elsif ($op eq 'rel32') {
 702                 push(@codes, 070+$oppos{'i'});
 703             } elsif ($op eq 'seg') {
 704                 push(@codes, 074+$oppos{'i'});
 705             } elsif ($op eq 'ibw') { # imm16 that can be bytified
 706                 if (!defined($s_pos)) {
 707                     die "$0: $line: $op without a +s byte\n";
 708                 }
 709                 $codes[$s_pos] += 0144;
 710                 push(@codes, 0140+$oppos{'i'});
 711             } elsif ($op eq 'ibd') { # imm32 that can be bytified
 712                 if (!defined($s_pos)) {
 713                     die "$0: $line: $op without a +s byte\n";
 714                 }
 715                 $codes[$s_pos] += 0154;
 716                 push(@codes, 0150+$oppos{'i'});
 717             } elsif ($op eq 'ibd,s') {
 718                 # imm32 that can be bytified, sign extended to 64 bits
 719                 if (!defined($s_pos)) {
 720                     die "$0: $line: $op without a +s byte\n";
 721                 }
 722                 $codes[$s_pos] += 0154;
 723                 push(@codes, 0250+$oppos{'i'});
 724             }
 725             $prefix_ok = 0;
 726         } elsif ($op eq '/is4') {
 727             if (!defined($oppos{'s'})) {
 728                 die "$0: $line: $op without 's' operand\n";
 729             }
 730             if (defined($oppos{'i'})) {
 731                 push(@codes, 0172, ($oppos{'s'} << 3)+$oppos{'i'});
 732             } else {
 733                 push(@codes, 0174, $oppos{'s'});
 734             }
 735             $prefix_ok = 0;
 736         } elsif ($op =~ /^\/is4\=([0-9]+)$/) {
 737             my $imm = $1;
 738             if (!defined($oppos{'s'})) {
 739                 die "$0: $line: $op without 's' operand\n";
 740             }
 741             if ($imm < 0 || $imm > 15) {
 742                 die "$0: $line: invalid imm4 value for $op: $imm\n";
 743             }
 744             push(@codes, 0173, ($oppos{'s'} << 4) + $imm);
 745             $prefix_ok = 0;
 746         } elsif ($op =~ /^([0-9a-f]{2})\+s$/) {
 747             if (!defined($oppos{'i'})) {
 748                 die "$0: $op without 'i' operand\n";
 749             }
 750             $s_pos = scalar @codes;
 751             push(@codes, $oppos{'i'}, hex $1);
 752             $prefix_ok = 0;
 753         } elsif ($op =~ /^([0-9a-f]{2})\+c$/) {
 754             push(@codes, 0330, hex $1);
 755             $prefix_ok = 0;
 756         } elsif ($op =~ /^\\([0-7]+|x[0-9a-f]{2})$/) {
 757             # Escape to enter literal bytecodes
 758             push(@codes, oct $1);
 759         } else {
 760             die "$0: unknown operation: $op\n";
 761         }
 762     }
 763
 764     return @codes;
 765 }