crypto/perlasm/x86_64-xlate.pl

   1 #!/usr/bin/env perl
   2
   3 # Ascetic x86_64 AT&T to MASM/NASM assembler translator by <appro>.
   4 #
   5 # Why AT&T to MASM and not vice versa? Several reasons. Because AT&T
   6 # format is way easier to parse. Because it's simpler to "gear" from
   7 # Unix ABI to Windows one [see cross-reference "card" at the end of
   8 # file]. Because Linux targets were available first...
   9 #
  10 # In addition the script also "distills" code suitable for GNU
  11 # assembler, so that it can be compiled with more rigid assemblers,
  12 # such as Solaris /usr/ccs/bin/as.
  13 #
  14 # This translator is not designed to convert *arbitrary* assembler
  15 # code from AT&T format to MASM one. It's designed to convert just
  16 # enough to provide for dual-ABI OpenSSL modules development...
  17 # There *are* limitations and you might have to modify your assembler
  18 # code or this script to achieve the desired result...
  19 #
  20 # Currently recognized limitations:
  21 #
  22 # - can't use multiple ops per line;
  23 #
  24 # Dual-ABI styling rules.
  25 #
  26 # 1. Adhere to Unix register and stack layout [see cross-reference
  27 #    ABI "card" at the end for explanation].
  28 # 2. Forget about "red zone," stick to more traditional blended
  29 #    stack frame allocation. If volatile storage is actually required
  30 #    that is. If not, just leave the stack as is.
  31 # 3. Functions tagged with ".type name,@function" get crafted with
  32 #    unified Win64 prologue and epilogue automatically. If you want
  33 #    to take care of ABI differences yourself, tag functions as
  34 #    ".type name,@abi-omnipotent" instead.
  35 # 4. To optimize the Win64 prologue you can specify number of input
  36 #    arguments as ".type name,@function,N." Keep in mind that if N is
  37 #    larger than 6, then you *have to* write "abi-omnipotent" code,
  38 #    because >6 cases can't be addressed with unified prologue.
  39 # 5. Name local labels as .L*, do *not* use dynamic labels such as 1:
  40 #    (sorry about latter).
  41 # 6. Don't use [or hand-code with .byte] "rep ret." "ret" mnemonic is
  42 #    required to identify the spots, where to inject Win64 epilogue!
  43 #    But on the pros, it's then prefixed with rep automatically:-)
  44 # 7. Stick to explicit ip-relative addressing. If you have to use
  45 #    GOTPCREL addressing, stick to mov symbol@GOTPCREL(%rip),%r??.
  46 #    Both are recognized and translated to proper Win64 addressing
  47 #    modes. To support legacy code a synthetic directive, .picmeup,
  48 #    is implemented. It puts address of the *next* instruction into
  49 #    target register, e.g.:
  50 #
  51 #               .picmeup        %rax
  52 #               lea             .Label-.(%rax),%rax
  53 #
  54 # 8. In order to provide for structured exception handling unified
  55 #    Win64 prologue copies %rsp value to %rax. For further details
  56 #    see SEH paragraph at the end.
  57 # 9. .init segment is allowed to contain calls to functions only.
  58 # a. If function accepts more than 4 arguments *and* >4th argument
  59 #    is declared as non 64-bit value, do clear its upper part.
  60 \f
  61 my $flavour = shift;
  62 my $output  = shift;
  63 if ($flavour =~ /\./) { $output = $flavour; undef $flavour; }
  64
  65 { my ($stddev,$stdino,@junk)=stat(STDOUT);
  66   my ($outdev,$outino,@junk)=stat($output);
  67
  68     open STDOUT,">$output" || die "can't open $output: $!"
  69         if ($stddev!=$outdev || $stdino!=$outino);
  70 }
  71
  72 my $gas=1;      $gas=0 if ($output =~ /\.asm$/);
  73 my $elf=1;      $elf=0 if (!$gas);
  74 my $win64=0;
  75 my $prefix="";
  76 my $decor=".L";
  77
  78 my $masmref=8 + 50727*2**-32;   # 8.00.50727 shipped with VS2005
  79 my $masm=0;
  80 my $PTR=" PTR";
  81
  82 my $nasmref=2.03;
  83 my $nasm=0;
  84
  85 if    ($flavour eq "mingw64")   { $gas=1; $elf=0; $win64=1;
  86                                   $prefix=`echo __USER_LABEL_PREFIX__ | $ENV{CC} -E -P -`;
  87                                   chomp($prefix);
  88                                 }
  89 elsif ($flavour eq "macosx")    { $gas=1; $elf=0; $prefix="_"; $decor="L\$"; }
  90 elsif ($flavour eq "masm")      { $gas=0; $elf=0; $masm=$masmref; $win64=1; $decor="\$L\$"; }
  91 elsif ($flavour eq "nasm")      { $gas=0; $elf=0; $nasm=$nasmref; $win64=1; $decor="\$L\$"; $PTR=""; }
  92 elsif (!$gas)
  93 {   if ($ENV{ASM} =~ m/nasm/ && `nasm -v` =~ m/version ([0-9]+)\.([0-9]+)/i)
  94     {   $nasm = $1 + $2*0.01; $PTR="";  }
  95     elsif (`ml64 2>&1` =~ m/Version ([0-9]+)\.([0-9]+)(\.([0-9]+))?/)
  96     {   $masm = $1 + $2*2**-16 + $4*2**-32;   }
  97     die "no assembler found on %PATH" if (!($nasm || $masm));
  98     $win64=1;
  99     $elf=0;
 100     $decor="\$L\$";
 101 }
 102
 103 my $current_segment;
 104 my $current_function;
 105 my %globals;
 106
 107 { package opcode;       # pick up opcodes
 108     sub re {
 109         my      $self = shift;  # single instance in enough...
 110         local   *line = shift;
 111         undef   $ret;
 112
 113         if ($line =~ /^([a-z][a-z0-9]*)/i) {
 114             $self->{op} = $1;
 115             $ret = $self;
 116             $line = substr($line,@+[0]); $line =~ s/^\s+//;
 117
 118             undef $self->{sz};
 119             if ($self->{op} =~ /^(movz)b.*/) {  # movz is pain...
 120                 $self->{op} = $1;
 121                 $self->{sz} = "b";
 122             } elsif ($self->{op} =~ /call|jmp/) {
 123                 $self->{sz} = "";
 124             } elsif ($self->{op} =~ /^p/ && $' !~ /^(ush|op|insrw)/) { # SSEn
 125                 $self->{sz} = "";
 126             } elsif ($self->{op} =~ /([a-z]{3,})([qlwb])$/) {
 127                 $self->{op} = $1;
 128                 $self->{sz} = $2;
 129             }
 130         }
 131         $ret;
 132     }
 133     sub size {
 134         my $self = shift;
 135         my $sz   = shift;
 136         $self->{sz} = $sz if (defined($sz) && !defined($self->{sz}));
 137         $self->{sz};
 138     }
 139     sub out {
 140         my $self = shift;
 141         if ($gas) {
 142             if ($self->{op} eq "movz") {        # movz is pain...
 143                 sprintf "%s%s%s",$self->{op},$self->{sz},shift;
 144             } elsif ($self->{op} =~ /^set/) {
 145                 "$self->{op}";
 146             } elsif ($self->{op} eq "ret") {
 147                 my $epilogue = "";
 148                 if ($win64 && $current_function->{abi} eq "svr4") {
 149                     $epilogue = "movq   8(%rsp),%rdi\n\t" .
 150                                 "movq   16(%rsp),%rsi\n\t";
 151                 }
 152                 $epilogue . ".byte      0xf3,0xc3";
 153             } elsif ($self->{op} eq "call" && !$elf && $current_segment eq ".init") {
 154                 ".p2align\t3\n\t.quad";
 155             } else {
 156                 "$self->{op}$self->{sz}";
 157             }
 158         } else {
 159             $self->{op} =~ s/^movz/movzx/;
 160             if ($self->{op} eq "ret") {
 161                 $self->{op} = "";
 162                 if ($win64 && $current_function->{abi} eq "svr4") {
 163                     $self->{op} = "mov  rdi,QWORD${PTR}[8+rsp]\t;WIN64 epilogue\n\t".
 164                                   "mov  rsi,QWORD${PTR}[16+rsp]\n\t";
 165                 }
 166                 $self->{op} .= "DB\t0F3h,0C3h\t\t;repret";
 167             } elsif ($self->{op} =~ /^(pop|push)f/) {
 168                 $self->{op} .= $self->{sz};
 169             } elsif ($self->{op} eq "call" && $current_segment eq ".CRT\$XCU") {
 170                 $self->{op} = "\tDQ";
 171             }
 172             $self->{op};
 173         }
 174     }
 175     sub mnemonic {
 176         my $self=shift;
 177         my $op=shift;
 178         $self->{op}=$op if (defined($op));
 179         $self->{op};
 180     }
 181 }
 182 { package const;        # pick up constants, which start with $
 183     sub re {
 184         my      $self = shift;  # single instance in enough...
 185         local   *line = shift;
 186         undef   $ret;
 187
 188         if ($line =~ /^\$([^,]+)/) {
 189             $self->{value} = $1;
 190             $ret = $self;
 191             $line = substr($line,@+[0]); $line =~ s/^\s+//;
 192         }
 193         $ret;
 194     }
 195     sub out {
 196         my $self = shift;
 197
 198         if ($gas) {
 199             # Solaris /usr/ccs/bin/as can't handle multiplications
 200             # in $self->{value}
 201             $self->{value} =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi;
 202             $self->{value} =~ s/([0-9]+\s*[\*\/\%]\s*[0-9]+)/eval($1)/eg;
 203             sprintf "\$%s",$self->{value};
 204         } else {
 205             $self->{value} =~ s/(0b[0-1]+)/oct($1)/eig;
 206             $self->{value} =~ s/0x([0-9a-f]+)/0$1h/ig if ($masm);
 207             sprintf "%s",$self->{value};
 208         }
 209     }
 210 }
 211 { package ea;           # pick up effective addresses: expr(%reg,%reg,scale)
 212     sub re {
 213         my      $self = shift;  # single instance in enough...
 214         local   *line = shift;
 215         undef   $ret;
 216
 217         # optional * ---vvv--- appears in indirect jmp/call
 218         if ($line =~ /^(\*?)([^\(,]*)\(([%\w,]+)\)/) {
 219             $self->{asterisk} = $1;
 220             $self->{label} = $2;
 221             ($self->{base},$self->{index},$self->{scale})=split(/,/,$3);
 222             $self->{scale} = 1 if (!defined($self->{scale}));
 223             $ret = $self;
 224             $line = substr($line,@+[0]); $line =~ s/^\s+//;
 225
 226             if ($win64 && $self->{label} =~ s/\@GOTPCREL//) {
 227                 die if (opcode->mnemonic() ne "mov");
 228                 opcode->mnemonic("lea");
 229             }
 230             $self->{base}  =~ s/^%//;
 231             $self->{index} =~ s/^%// if (defined($self->{index}));
 232         }
 233         $ret;
 234     }
 235     sub size {}
 236     sub out {
 237         my $self = shift;
 238         my $sz = shift;
 239
 240         $self->{label} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei;
 241         $self->{label} =~ s/\.L/$decor/g;
 242
 243         # Silently convert all EAs to 64-bit. This is required for
 244         # elder GNU assembler and results in more compact code,
 245         # *but* most importantly AES module depends on this feature!
 246         $self->{index} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/;
 247         $self->{base}  =~ s/^[er](.?[0-9xpi])[d]?$/r\1/;
 248
 249         if ($gas) {
 250             # Solaris /usr/ccs/bin/as can't handle multiplications
 251             # in $self->{label}, new gas requires sign extension...
 252             use integer;
 253             $self->{label} =~ s/(?<![\w\$\.])(0x?[0-9a-f]+)/oct($1)/egi;
 254             $self->{label} =~ s/([0-9]+\s*[\*\/\%]\s*[0-9]+)/eval($1)/eg;
 255             $self->{label} =~ s/([0-9]+)/$1<<32>>32/eg;
 256             $self->{label} =~ s/^___imp_/__imp__/   if ($flavour eq "mingw64");
 257
 258             if (defined($self->{index})) {
 259                 sprintf "%s%s(%s,%%%s,%d)",$self->{asterisk},
 260                                         $self->{label},
 261                                         $self->{base}?"%$self->{base}":"",
 262                                         $self->{index},$self->{scale};
 263             } else {
 264                 sprintf "%s%s(%%%s)",   $self->{asterisk},$self->{label},$self->{base};
 265             }
 266         } else {
 267             %szmap = (  b=>"BYTE$PTR", w=>"WORD$PTR", l=>"DWORD$PTR",
 268                         q=>"QWORD$PTR",o=>"OWORD$PTR",x=>"XMMWORD$PTR" );
 269
 270             $self->{label} =~ s/\./\$/g;
 271             $self->{label} =~ s/(?<![\w\$\.])0x([0-9a-f]+)/0$1h/ig;
 272             $self->{label} = "($self->{label})" if ($self->{label} =~ /[\*\+\-\/]/);
 273             $sz="q" if ($self->{asterisk});
 274
 275             if (defined($self->{index})) {
 276                 sprintf "%s[%s%s*%d%s]",$szmap{$sz},
 277                                         $self->{label}?"$self->{label}+":"",
 278                                         $self->{index},$self->{scale},
 279                                         $self->{base}?"+$self->{base}":"";
 280             } elsif ($self->{base} eq "rip") {
 281                 sprintf "%s[%s]",$szmap{$sz},$self->{label};
 282             } else {
 283                 sprintf "%s[%s%s]",$szmap{$sz},
 284                                         $self->{label}?"$self->{label}+":"",
 285                                         $self->{base};
 286             }
 287         }
 288     }
 289 }
 290 { package register;     # pick up registers, which start with %.
 291     sub re {
 292         my      $class = shift; # muliple instances...
 293         my      $self = {};
 294         local   *line = shift;
 295         undef   $ret;
 296
 297         # optional * ---vvv--- appears in indirect jmp/call
 298         if ($line =~ /^(\*?)%(\w+)/) {
 299             bless $self,$class;
 300             $self->{asterisk} = $1;
 301             $self->{value} = $2;
 302             $ret = $self;
 303             $line = substr($line,@+[0]); $line =~ s/^\s+//;
 304         }
 305         $ret;
 306     }
 307     sub size {
 308         my      $self = shift;
 309         undef   $ret;
 310
 311         if    ($self->{value} =~ /^r[\d]+b$/i)  { $ret="b"; }
 312         elsif ($self->{value} =~ /^r[\d]+w$/i)  { $ret="w"; }
 313         elsif ($self->{value} =~ /^r[\d]+d$/i)  { $ret="l"; }
 314         elsif ($self->{value} =~ /^r[\w]+$/i)   { $ret="q"; }
 315         elsif ($self->{value} =~ /^[a-d][hl]$/i){ $ret="b"; }
 316         elsif ($self->{value} =~ /^[\w]{2}l$/i) { $ret="b"; }
 317         elsif ($self->{value} =~ /^[\w]{2}$/i)  { $ret="w"; }
 318         elsif ($self->{value} =~ /^e[a-z]{2}$/i){ $ret="l"; }
 319
 320         $ret;
 321     }
 322     sub out {
 323         my $self = shift;
 324         if ($gas)       { sprintf "%s%%%s",$self->{asterisk},$self->{value}; }
 325         else            { $self->{value}; }
 326     }
 327 }
 328 { package label;        # pick up labels, which end with :
 329     sub re {
 330         my      $self = shift;  # single instance is enough...
 331         local   *line = shift;
 332         undef   $ret;
 333
 334         if ($line =~ /(^[\.\w]+)\:/) {
 335             $self->{value} = $1;
 336             $ret = $self;
 337             $line = substr($line,@+[0]); $line =~ s/^\s+//;
 338
 339             $self->{value} =~ s/^\.L/$decor/;
 340         }
 341         $ret;
 342     }
 343     sub out {
 344         my $self = shift;
 345
 346         if ($gas) {
 347             my $func = ($globals{$self->{value}} or $self->{value}) . ":";
 348             if ($win64  &&
 349                         $current_function->{name} eq $self->{value} &&
 350                         $current_function->{abi} eq "svr4") {
 351                 $func .= "\n";
 352                 $func .= "      movq    %rdi,8(%rsp)\n";
 353                 $func .= "      movq    %rsi,16(%rsp)\n";
 354                 $func .= "      movq    %rsp,%rax\n";
 355                 $func .= "${decor}SEH_begin_$current_function->{name}:\n";
 356                 my $narg = $current_function->{narg};
 357                 $narg=6 if (!defined($narg));
 358                 $func .= "      movq    %rcx,%rdi\n" if ($narg>0);
 359                 $func .= "      movq    %rdx,%rsi\n" if ($narg>1);
 360                 $func .= "      movq    %r8,%rdx\n"  if ($narg>2);
 361                 $func .= "      movq    %r9,%rcx\n"  if ($narg>3);
 362                 $func .= "      movq    40(%rsp),%r8\n" if ($narg>4);
 363                 $func .= "      movq    48(%rsp),%r9\n" if ($narg>5);
 364             }
 365             $func;
 366         } elsif ($self->{value} ne "$current_function->{name}") {
 367             $self->{value} .= ":" if ($masm && $ret!~m/^\$/);
 368             $self->{value} . ":";
 369         } elsif ($win64 && $current_function->{abi} eq "svr4") {
 370             my $func =  "$current_function->{name}" .
 371                         ($nasm ? ":" : "\tPROC $current_function->{scope}") .
 372                         "\n";
 373             $func .= "  mov     QWORD${PTR}[8+rsp],rdi\t;WIN64 prologue\n";
 374             $func .= "  mov     QWORD${PTR}[16+rsp],rsi\n";
 375             $func .= "  mov     rax,rsp\n";
 376             $func .= "${decor}SEH_begin_$current_function->{name}:";
 377             $func .= ":" if ($masm);
 378             $func .= "\n";
 379             my $narg = $current_function->{narg};
 380             $narg=6 if (!defined($narg));
 381             $func .= "  mov     rdi,rcx\n" if ($narg>0);
 382             $func .= "  mov     rsi,rdx\n" if ($narg>1);
 383             $func .= "  mov     rdx,r8\n"  if ($narg>2);
 384             $func .= "  mov     rcx,r9\n"  if ($narg>3);
 385             $func .= "  mov     r8,QWORD${PTR}[40+rsp]\n" if ($narg>4);
 386             $func .= "  mov     r9,QWORD${PTR}[48+rsp]\n" if ($narg>5);
 387             $func .= "\n";
 388         } else {
 389            "$current_function->{name}".
 390                         ($nasm ? ":" : "\tPROC $current_function->{scope}");
 391         }
 392     }
 393 }
 394 { package expr;         # pick up expressioins
 395     sub re {
 396         my      $self = shift;  # single instance is enough...
 397         local   *line = shift;
 398         undef   $ret;
 399
 400         if ($line =~ /(^[^,]+)/) {
 401             $self->{value} = $1;
 402             $ret = $self;
 403             $line = substr($line,@+[0]); $line =~ s/^\s+//;
 404
 405             $self->{value} =~ s/\@PLT// if (!$elf);
 406             $self->{value} =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei;
 407             $self->{value} =~ s/\.L/$decor/g;
 408         }
 409         $ret;
 410     }
 411     sub out {
 412         my $self = shift;
 413         if ($nasm && opcode->mnemonic()=~m/^j/) {
 414             "NEAR ".$self->{value};
 415         } else {
 416             $self->{value};
 417         }
 418     }
 419 }
 420 { package directive;    # pick up directives, which start with .
 421     sub re {
 422         my      $self = shift;  # single instance is enough...
 423         local   *line = shift;
 424         undef   $ret;
 425         my      $dir;
 426         my      %opcode =       # lea 2f-1f(%rip),%dst; 1: nop; 2:
 427                 (       "%rax"=>0x01058d48,     "%rcx"=>0x010d8d48,
 428                         "%rdx"=>0x01158d48,     "%rbx"=>0x011d8d48,
 429                         "%rsp"=>0x01258d48,     "%rbp"=>0x012d8d48,
 430                         "%rsi"=>0x01358d48,     "%rdi"=>0x013d8d48,
 431                         "%r8" =>0x01058d4c,     "%r9" =>0x010d8d4c,
 432                         "%r10"=>0x01158d4c,     "%r11"=>0x011d8d4c,
 433                         "%r12"=>0x01258d4c,     "%r13"=>0x012d8d4c,
 434                         "%r14"=>0x01358d4c,     "%r15"=>0x013d8d4c      );
 435
 436         if ($line =~ /^\s*(\.\w+)/) {
 437             $dir = $1;
 438             $ret = $self;
 439             undef $self->{value};
 440             $line = substr($line,@+[0]); $line =~ s/^\s+//;
 441
 442             SWITCH: for ($dir) {
 443                 /\.picmeup/ && do { if ($line =~ /(%r[\w]+)/i) {
 444                                         $dir="\t.long";
 445                                         $line=sprintf "0x%x,0x90000000",$opcode{$1};
 446                                     }
 447                                     last;
 448                                   };
 449                 /\.global|\.globl|\.extern/
 450                             && do { $globals{$line} = $prefix . $line;
 451                                     $line = $globals{$line} if ($prefix);
 452                                     last;
 453                                   };
 454                 /\.type/    && do { ($sym,$type,$narg) = split(',',$line);
 455                                     if ($type eq "\@function") {
 456                                         undef $current_function;
 457                                         $current_function->{name} = $sym;
 458                                         $current_function->{abi}  = "svr4";
 459                                         $current_function->{narg} = $narg;
 460                                         $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE";
 461                                     } elsif ($type eq "\@abi-omnipotent") {
 462                                         undef $current_function;
 463                                         $current_function->{name} = $sym;
 464                                         $current_function->{scope} = defined($globals{$sym})?"PUBLIC":"PRIVATE";
 465                                     }
 466                                     $line =~ s/\@abi\-omnipotent/\@function/;
 467                                     $line =~ s/\@function.*/\@function/;
 468                                     last;
 469                                   };
 470                 /\.asciz/   && do { if ($line =~ /^"(.*)"$/) {
 471                                         $dir  = ".byte";
 472                                         $line = join(",",unpack("C*",$1),0);
 473                                     }
 474                                     last;
 475                                   };
 476                 /\.rva|\.long|\.quad/
 477                             && do { $line =~ s/([_a-z][_a-z0-9]*)/$globals{$1} or $1/gei;
 478                                     $line =~ s/\.L/$decor/g;
 479                                     last;
 480                                   };
 481             }
 482
 483             if ($gas) {
 484                 $self->{value} = $dir . "\t" . $line;
 485
 486                 if ($dir =~ /\.extern/) {
 487                     $self->{value} = ""; # swallow extern
 488                 } elsif (!$elf && $dir =~ /\.type/) {
 489                     $self->{value} = "";
 490                     $self->{value} = ".def\t" . ($globals{$1} or $1) . ";\t" .
 491                                 (defined($globals{$1})?".scl 2;":".scl 3;") .
 492                                 "\t.type 32;\t.endef"
 493                                 if ($win64 && $line =~ /([^,]+),\@function/);
 494                 } elsif (!$elf && $dir =~ /\.size/) {
 495                     $self->{value} = "";
 496                     if (defined($current_function)) {
 497                         $self->{value} .= "${decor}SEH_end_$current_function->{name}:"
 498                                 if ($win64 && $current_function->{abi} eq "svr4");
 499                         undef $current_function;
 500                     }
 501                 } elsif (!$elf && $dir =~ /\.align/) {
 502                     $self->{value} = ".p2align\t" . (log($line)/log(2));
 503                 } elsif ($dir eq ".section") {
 504                     $current_segment=$line;
 505                     if (!$elf && $current_segment eq ".init") {
 506                         if      ($flavour eq "macosx")  { $self->{value} = ".mod_init_func"; }
 507                         elsif   ($flavour eq "mingw64") { $self->{value} = ".section\t.ctors"; }
 508                     }
 509                 } elsif ($dir =~ /\.(text|data)/) {
 510                     $current_segment=".$1";
 511                 } elsif ($dir =~ /\.hidden/) {
 512                     if    ($flavour eq "macosx")  { $self->{value} = ".private_extern\t$prefix$line"; }
 513                     elsif ($flavour eq "mingw64") { $self->{value} = ""; }
 514                 } elsif ($dir =~ /\.comm/) {
 515                     $self->{value} = "$dir\t$prefix$line";
 516                 }
 517                 $line = "";
 518                 return $self;
 519             }
 520
 521             # non-gas case or nasm/masm
 522             SWITCH: for ($dir) {
 523                 /\.text/    && do { my $v=undef;
 524                                     if ($nasm) {
 525                                         $v="section     .text code align=64\n";
 526                                     } else {
 527                                         $v="$current_segment\tENDS\n" if ($current_segment);
 528                                         $current_segment = ".text\$";
 529                                         $v.="$current_segment\tSEGMENT ";
 530                                         $v.=$masm>=$masmref ? "ALIGN(64)" : "PAGE";
 531                                         $v.=" 'CODE'";
 532                                     }
 533                                     $self->{value} = $v;
 534                                     last;
 535                                   };
 536                 /\.data/    && do { my $v=undef;
 537                                     if ($nasm) {
 538                                         $v="section     .data data align=8\n";
 539                                     } else {
 540                                         $v="$current_segment\tENDS\n" if ($current_segment);
 541                                         $current_segment = "_DATA";
 542                                         $v.="$current_segment\tSEGMENT";
 543                                     }
 544                                     $self->{value} = $v;
 545                                     last;
 546                                   };
 547                 /\.section/ && do { my $v=undef;
 548                                     $line =~ s/([^,]*).*/$1/;
 549                                     $line = ".CRT\$XCU" if ($line eq ".init");
 550                                     if ($nasm) {
 551                                         $v="section     $line";
 552                                         if ($line=~/\.([px])data/) {
 553                                             $v.=" rdata align=";
 554                                             $v.=$1 eq "p"? 4 : 8;
 555                                         } elsif ($line=~/\.CRT\$/i) {
 556                                             $v.=" rdata align=8";
 557                                         }
 558                                     } else {
 559                                         $v="$current_segment\tENDS\n" if ($current_segment);
 560                                         $v.="$line\tSEGMENT";
 561                                         if ($line=~/\.([px])data/) {
 562                                             $v.=" READONLY";
 563                                             $v.=" ALIGN(".($1 eq "p" ? 4 : 8).")" if ($masm>=$masmref);
 564                                         } elsif ($line=~/\.CRT\$/i) {
 565                                             $v.=" READONLY DWORD";
 566                                         }
 567                                     }
 568                                     $current_segment = $line;
 569                                     $self->{value} = $v;
 570                                     last;
 571                                   };
 572                 /\.extern/  && do { $self->{value}  = "EXTERN\t".$line;
 573                                     $self->{value} .= ":NEAR" if ($masm);
 574                                     last;
 575                                   };
 576                 /\.globl|.global/
 577                             && do { $self->{value}  = $masm?"PUBLIC":"global";
 578                                     $self->{value} .= "\t".$line;
 579                                     last;
 580                                   };
 581                 /\.size/    && do { if (defined($current_function)) {
 582                                         undef $self->{value};
 583                                         if ($current_function->{abi} eq "svr4") {
 584                                             $self->{value}="${decor}SEH_end_$current_function->{name}:";
 585                                             $self->{value}.=":\n" if($masm);
 586                                         }
 587                                         $self->{value}.="$current_function->{name}\tENDP" if($masm);
 588                                         undef $current_function;
 589                                     }
 590                                     last;
 591                                   };
 592                 /\.align/   && do { $self->{value} = "ALIGN\t".$line; last; };
 593                 /\.(value|long|rva|quad)/
 594                             && do { my $sz  = substr($1,0,1);
 595                                     my @arr = split(/,\s*/,$line);
 596                                     my $last = pop(@arr);
 597                                     my $conv = sub  {   my $var=shift;
 598                                                         $var=~s/^(0b[0-1]+)/oct($1)/eig;
 599                                                         $var=~s/^0x([0-9a-f]+)/0$1h/ig if ($masm);
 600                                                         if ($sz eq "D" && ($current_segment=~/.[px]data/ || $dir eq ".rva"))
 601                                                         { $var=~s/([_a-z\$\@][_a-z0-9\$\@]*)/$nasm?"$1 wrt ..imagebase":"imagerel $1"/egi; }
 602                                                         $var;
 603                                                     };
 604
 605                                     $sz =~ tr/bvlrq/BWDDQ/;
 606                                     $self->{value} = "\tD$sz\t";
 607                                     for (@arr) { $self->{value} .= &$conv($_).","; }
 608                                     $self->{value} .= &$conv($last);
 609                                     last;
 610                                   };
 611                 /\.byte/    && do { my @str=split(/,\s*/,$line);
 612                                     map(s/(0b[0-1]+)/oct($1)/eig,@str);
 613                                     map(s/0x([0-9a-f]+)/0$1h/ig,@str) if ($masm);
 614                                     while ($#str>15) {
 615                                         $self->{value}.="DB\t"
 616                                                 .join(",",@str[0..15])."\n";
 617                                         foreach (0..15) { shift @str; }
 618                                     }
 619                                     $self->{value}.="DB\t"
 620                                                 .join(",",@str) if (@str);
 621                                     last;
 622                                   };
 623                 /\.comm/    && do { my @str=split(/,\s*/,$line);
 624                                     my $v=undef;
 625                                     if ($nasm) {
 626                                         $v.="common     $prefix@str[0] @str[1]:near";
 627                                     } else {
 628                                         $v="$current_segment\tENDS\n" if ($current_segment);
 629                                         $current_segment = ".data";
 630                                         $v.="$current_segment\tSEGMENT\n";
 631                                         $v.="COMM       @str[0]:DWORD:".@str[1]/4;
 632                                     }
 633                                     $self->{value} = $v;
 634                                     last;
 635                                   };
 636             }
 637             $line = "";
 638         }
 639
 640         $ret;
 641     }
 642     sub out {
 643         my $self = shift;
 644         $self->{value};
 645     }
 646 }
 647
 648 sub rex {
 649  local *opcode=shift;
 650  my ($dst,$src,$rex)=@_;
 651
 652    $rex|=0x04 if($dst>=8);
 653    $rex|=0x01 if($src>=8);
 654    push @opcode,($rex|0x40) if ($rex);
 655 }
 656
 657 # older gas and ml64 don't handle SSE>2 instructions
 658 my %regrm = (   "%eax"=>0, "%ecx"=>1, "%edx"=>2, "%ebx"=>3,
 659                 "%esp"=>4, "%ebp"=>5, "%esi"=>6, "%edi"=>7      );
 660
 661 my $pextrd = sub {
 662     if (shift =~ /\$([0-9]+),%xmm([0-9]+),(%\w+)/) {
 663       my @opcode=(0x66);
 664         $imm=$1;
 665         $src=$2;
 666         $dst=$3;
 667         if ($dst =~ /%r([0-9]+)d/)      { $dst = $1; }
 668         elsif ($dst =~ /%e/)            { $dst = $regrm{$dst}; }
 669         rex(\@opcode,$src,$dst);
 670         push @opcode,0x0f,0x3a,0x16;
 671         push @opcode,0xc0|(($src&7)<<3)|($dst&7);       # ModR/M
 672         push @opcode,$imm;
 673         @opcode;
 674     } else {
 675         ();
 676     }
 677 };
 678
 679 my $pinsrd = sub {
 680     if (shift =~ /\$([0-9]+),(%\w+),%xmm([0-9]+)/) {
 681       my @opcode=(0x66);
 682         $imm=$1;
 683         $src=$2;
 684         $dst=$3;
 685         if ($src =~ /%r([0-9]+)/)       { $src = $1; }
 686         elsif ($src =~ /%e/)            { $src = $regrm{$src}; }
 687         rex(\@opcode,$dst,$src);
 688         push @opcode,0x0f,0x3a,0x22;
 689         push @opcode,0xc0|(($dst&7)<<3)|($src&7);       # ModR/M
 690         push @opcode,$imm;
 691         @opcode;
 692     } else {
 693         ();
 694     }
 695 };
 696
 697 my $pshufb = sub {
 698     if (shift =~ /%xmm([0-9]+),%xmm([0-9]+)/) {
 699       my @opcode=(0x66);
 700         rex(\@opcode,$2,$1);
 701         push @opcode,0x0f,0x38,0x00;
 702         push @opcode,0xc0|($1&7)|(($2&7)<<3);           # ModR/M
 703         @opcode;
 704     } else {
 705         ();
 706     }
 707 };
 708
 709 my $palignr = sub {
 710     if (shift =~ /\$([0-9]+),%xmm([0-9]+),%xmm([0-9]+)/) {
 711       my @opcode=(0x66);
 712         rex(\@opcode,$3,$2);
 713         push @opcode,0x0f,0x3a,0x0f;
 714         push @opcode,0xc0|($2&7)|(($3&7)<<3);           # ModR/M
 715         push @opcode,$1;
 716         @opcode;
 717     } else {
 718         ();
 719     }
 720 };
 721
 722 my $pclmulqdq = sub {
 723     if (shift =~ /\$([x0-9a-f]+),\s*%xmm([0-9]+),\s*%xmm([0-9]+)/) {
 724       my @opcode=(0x66);
 725         rex(\@opcode,$3,$2);
 726         push @opcode,0x0f,0x3a,0x44;
 727         push @opcode,0xc0|($2&7)|(($3&7)<<3);           # ModR/M
 728         my $c=$1;
 729         push @opcode,$c=~/^0/?oct($c):$c;
 730         @opcode;
 731     } else {
 732         ();
 733     }
 734 };
 735
 736 if ($nasm) {
 737     print <<___;
 738 default rel
 739 %define XMMWORD
 740 ___
 741 } elsif ($masm) {
 742     print <<___;
 743 OPTION  DOTNAME
 744 ___
 745 }
 746 while($line=<>) {
 747
 748     chomp($line);
 749
 750     $line =~ s|[#!].*$||;       # get rid of asm-style comments...
 751     $line =~ s|/\*.*\*/||;      # ... and C-style comments...
 752     $line =~ s|^\s+||;          # ... and skip white spaces in beginning
 753
 754     undef $label;
 755     undef $opcode;
 756     undef @args;
 757
 758     if ($label=label->re(\$line))       { print $label->out(); }
 759
 760     if (directive->re(\$line)) {
 761         printf "%s",directive->out();
 762     } elsif ($opcode=opcode->re(\$line)) {
 763         my $asm = eval("\$".$opcode->mnemonic());
 764         undef @bytes;
 765
 766         if ((ref($asm) eq 'CODE') && scalar(@bytes=&$asm($line))) {
 767             print $gas?".byte\t":"DB\t",join(',',@bytes),"\n";
 768             next;
 769         }
 770
 771         ARGUMENT: while (1) {
 772         my $arg;
 773
 774         if ($arg=register->re(\$line))  { opcode->size($arg->size()); }
 775         elsif ($arg=const->re(\$line))  { }
 776         elsif ($arg=ea->re(\$line))     { }
 777         elsif ($arg=expr->re(\$line))   { }
 778         else                            { last ARGUMENT; }
 779
 780         push @args,$arg;
 781
 782         last ARGUMENT if ($line !~ /^,/);
 783
 784         $line =~ s/^,\s*//;
 785         } # ARGUMENT:
 786
 787         if ($#args>=0) {
 788             my $insn;
 789             my $sz=opcode->size();
 790
 791             if ($gas) {
 792                 $insn = $opcode->out($#args>=1?$args[$#args]->size():$sz);
 793                 @args = map($_->out($sz),@args);
 794                 printf "\t%s\t%s",$insn,join(",",@args);
 795             } else {
 796                 $insn = $opcode->out();
 797                 foreach (@args) {
 798                     my $arg = $_->out();
 799                     # $insn.=$sz compensates for movq, pinsrw, ...
 800                     if ($arg =~ /^xmm[0-9]+$/) { $insn.=$sz; $sz="x" if(!$sz); last; }
 801                     if ($arg =~ /^mm[0-9]+$/)  { $insn.=$sz; $sz="q" if(!$sz); last; }
 802                 }
 803                 @args = reverse(@args);
 804                 undef $sz if ($nasm && $opcode->mnemonic() eq "lea");
 805                 printf "\t%s\t%s",$insn,join(",",map($_->out($sz),@args));
 806             }
 807         } else {
 808             printf "\t%s",$opcode->out();
 809         }
 810     }
 811
 812     print $line,"\n";
 813 }
 814
 815 print "\n$current_segment\tENDS\n"      if ($current_segment && $masm);
 816 print "END\n"                           if ($masm);
 817
 818 close STDOUT;
 819
 820 \f#################################################
 821 # Cross-reference x86_64 ABI "card"
 822 #
 823 #               Unix            Win64
 824 # %rax          *               *
 825 # %rbx          -               -
 826 # %rcx          #4              #1
 827 # %rdx          #3              #2
 828 # %rsi          #2              -
 829 # %rdi          #1              -
 830 # %rbp          -               -
 831 # %rsp          -               -
 832 # %r8           #5              #3
 833 # %r9           #6              #4
 834 # %r10          *               *
 835 # %r11          *               *
 836 # %r12          -               -
 837 # %r13          -               -
 838 # %r14          -               -
 839 # %r15          -               -
 840 #
 841 # (*)   volatile register
 842 # (-)   preserved by callee
 843 # (#)   Nth argument, volatile
 844 #
 845 # In Unix terms top of stack is argument transfer area for arguments
 846 # which could not be accomodated in registers. Or in other words 7th
 847 # [integer] argument resides at 8(%rsp) upon function entry point.
 848 # 128 bytes above %rsp constitute a "red zone" which is not touched
 849 # by signal handlers and can be used as temporal storage without
 850 # allocating a frame.
 851 #
 852 # In Win64 terms N*8 bytes on top of stack is argument transfer area,
 853 # which belongs to/can be overwritten by callee. N is the number of
 854 # arguments passed to callee, *but* not less than 4! This means that
 855 # upon function entry point 5th argument resides at 40(%rsp), as well
 856 # as that 32 bytes from 8(%rsp) can always be used as temporal
 857 # storage [without allocating a frame]. One can actually argue that
 858 # one can assume a "red zone" above stack pointer under Win64 as well.
 859 # Point is that at apparently no occasion Windows kernel would alter
 860 # the area above user stack pointer in true asynchronous manner...
 861 #
 862 # All the above means that if assembler programmer adheres to Unix
 863 # register and stack layout, but disregards the "red zone" existense,
 864 # it's possible to use following prologue and epilogue to "gear" from
 865 # Unix to Win64 ABI in leaf functions with not more than 6 arguments.
 866 #
 867 # omnipotent_function:
 868 # ifdef WIN64
 869 #       movq    %rdi,8(%rsp)
 870 #       movq    %rsi,16(%rsp)
 871 #       movq    %rcx,%rdi       ; if 1st argument is actually present
 872 #       movq    %rdx,%rsi       ; if 2nd argument is actually ...
 873 #       movq    %r8,%rdx        ; if 3rd argument is ...
 874 #       movq    %r9,%rcx        ; if 4th argument ...
 875 #       movq    40(%rsp),%r8    ; if 5th ...
 876 #       movq    48(%rsp),%r9    ; if 6th ...
 877 # endif
 878 #       ...
 879 # ifdef WIN64
 880 #       movq    8(%rsp),%rdi
 881 #       movq    16(%rsp),%rsi
 882 # endif
 883 #       ret
 884 #
 885 \f#################################################
 886 # Win64 SEH, Structured Exception Handling.
 887 #
 888 # Unlike on Unix systems(*) lack of Win64 stack unwinding information
 889 # has undesired side-effect at run-time: if an exception is raised in
 890 # assembler subroutine such as those in question (basically we're
 891 # referring to segmentation violations caused by malformed input
 892 # parameters), the application is briskly terminated without invoking
 893 # any exception handlers, most notably without generating memory dump
 894 # or any user notification whatsoever. This poses a problem. It's
 895 # possible to address it by registering custom language-specific
 896 # handler that would restore processor context to the state at
 897 # subroutine entry point and return "exception is not handled, keep
 898 # unwinding" code. Writing such handler can be a challenge... But it's
 899 # doable, though requires certain coding convention. Consider following
 900 # snippet:
 901 #
 902 # .type function,@function
 903 # function:
 904 #       movq    %rsp,%rax       # copy rsp to volatile register
 905 #       pushq   %r15            # save non-volatile registers
 906 #       pushq   %rbx
 907 #       pushq   %rbp
 908 #       movq    %rsp,%r11
 909 #       subq    %rdi,%r11       # prepare [variable] stack frame
 910 #       andq    $-64,%r11
 911 #       movq    %rax,0(%r11)    # check for exceptions
 912 #       movq    %r11,%rsp       # allocate [variable] stack frame
 913 #       movq    %rax,0(%rsp)    # save original rsp value
 914 # magic_point:
 915 #       ...
 916 #       movq    0(%rsp),%rcx    # pull original rsp value
 917 #       movq    -24(%rcx),%rbp  # restore non-volatile registers
 918 #       movq    -16(%rcx),%rbx
 919 #       movq    -8(%rcx),%r15
 920 #       movq    %rcx,%rsp       # restore original rsp
 921 #       ret
 922 # .size function,.-function
 923 #
 924 # The key is that up to magic_point copy of original rsp value remains
 925 # in chosen volatile register and no non-volatile register, except for
 926 # rsp, is modified. While past magic_point rsp remains constant till
 927 # the very end of the function. In this case custom language-specific
 928 # exception handler would look like this:
 929 #
 930 # EXCEPTION_DISPOSITION handler (EXCEPTION_RECORD *rec,ULONG64 frame,
 931 #               CONTEXT *context,DISPATCHER_CONTEXT *disp)
 932 # {     ULONG64 *rsp = (ULONG64 *)context->Rax;
 933 #       if (context->Rip >= magic_point)
 934 #       {   rsp = ((ULONG64 **)context->Rsp)[0];
 935 #           context->Rbp = rsp[-3];
 936 #           context->Rbx = rsp[-2];
 937 #           context->R15 = rsp[-1];
 938 #       }
 939 #       context->Rsp = (ULONG64)rsp;
 940 #       context->Rdi = rsp[1];
 941 #       context->Rsi = rsp[2];
 942 #
 943 #       memcpy (disp->ContextRecord,context,sizeof(CONTEXT));
 944 #       RtlVirtualUnwind(UNW_FLAG_NHANDLER,disp->ImageBase,
 945 #               dips->ControlPc,disp->FunctionEntry,disp->ContextRecord,
 946 #               &disp->HandlerData,&disp->EstablisherFrame,NULL);
 947 #       return ExceptionContinueSearch;
 948 # }
 949 #
 950 # It's appropriate to implement this handler in assembler, directly in
 951 # function's module. In order to do that one has to know members'
 952 # offsets in CONTEXT and DISPATCHER_CONTEXT structures and some constant
 953 # values. Here they are:
 954 #
 955 #       CONTEXT.Rax                             120
 956 #       CONTEXT.Rcx                             128
 957 #       CONTEXT.Rdx                             136
 958 #       CONTEXT.Rbx                             144
 959 #       CONTEXT.Rsp                             152
 960 #       CONTEXT.Rbp                             160
 961 #       CONTEXT.Rsi                             168
 962 #       CONTEXT.Rdi                             176
 963 #       CONTEXT.R8                              184
 964 #       CONTEXT.R9                              192
 965 #       CONTEXT.R10                             200
 966 #       CONTEXT.R11                             208
 967 #       CONTEXT.R12                             216
 968 #       CONTEXT.R13                             224
 969 #       CONTEXT.R14                             232
 970 #       CONTEXT.R15                             240
 971 #       CONTEXT.Rip                             248
 972 #       CONTEXT.Xmm6                            512
 973 #       sizeof(CONTEXT)                         1232
 974 #       DISPATCHER_CONTEXT.ControlPc            0
 975 #       DISPATCHER_CONTEXT.ImageBase            8
 976 #       DISPATCHER_CONTEXT.FunctionEntry        16
 977 #       DISPATCHER_CONTEXT.EstablisherFrame     24
 978 #       DISPATCHER_CONTEXT.TargetIp             32
 979 #       DISPATCHER_CONTEXT.ContextRecord        40
 980 #       DISPATCHER_CONTEXT.LanguageHandler      48
 981 #       DISPATCHER_CONTEXT.HandlerData          56
 982 #       UNW_FLAG_NHANDLER                       0
 983 #       ExceptionContinueSearch                 1
 984 #
 985 # In order to tie the handler to the function one has to compose
 986 # couple of structures: one for .xdata segment and one for .pdata.
 987 #
 988 # UNWIND_INFO structure for .xdata segment would be
 989 #
 990 # function_unwind_info:
 991 #       .byte   9,0,0,0
 992 #       .rva    handler
 993 #
 994 # This structure designates exception handler for a function with
 995 # zero-length prologue, no stack frame or frame register.
 996 #
 997 # To facilitate composing of .pdata structures, auto-generated "gear"
 998 # prologue copies rsp value to rax and denotes next instruction with
 999 # .LSEH_begin_{function_name} label. This essentially defines the SEH
1000 # styling rule mentioned in the beginning. Position of this label is
1001 # chosen in such manner that possible exceptions raised in the "gear"
1002 # prologue would be accounted to caller and unwound from latter's frame.
1003 # End of function is marked with respective .LSEH_end_{function_name}
1004 # label. To summarize, .pdata segment would contain
1005 #
1006 #       .rva    .LSEH_begin_function
1007 #       .rva    .LSEH_end_function
1008 #       .rva    function_unwind_info
1009 #
1010 # Reference to functon_unwind_info from .xdata segment is the anchor.
1011 # In case you wonder why references are 32-bit .rvas and not 64-bit
1012 # .quads. References put into these two segments are required to be
1013 # *relative* to the base address of the current binary module, a.k.a.
1014 # image base. No Win64 module, be it .exe or .dll, can be larger than
1015 # 2GB and thus such relative references can be and are accommodated in
1016 # 32 bits.
1017 #
1018 # Having reviewed the example function code, one can argue that "movq
1019 # %rsp,%rax" above is redundant. It is not! Keep in mind that on Unix
1020 # rax would contain an undefined value. If this "offends" you, use
1021 # another register and refrain from modifying rax till magic_point is
1022 # reached, i.e. as if it was a non-volatile register. If more registers
1023 # are required prior [variable] frame setup is completed, note that
1024 # nobody says that you can have only one "magic point." You can
1025 # "liberate" non-volatile registers by denoting last stack off-load
1026 # instruction and reflecting it in finer grade unwind logic in handler.
1027 # After all, isn't it why it's called *language-specific* handler...
1028 #
1029 # Attentive reader can notice that exceptions would be mishandled in
1030 # auto-generated "gear" epilogue. Well, exception effectively can't
1031 # occur there, because if memory area used by it was subject to
1032 # segmentation violation, then it would be raised upon call to the
1033 # function (and as already mentioned be accounted to caller, which is
1034 # not a problem). If you're still not comfortable, then define tail
1035 # "magic point" just prior ret instruction and have handler treat it...
1036 #
1037 # (*)   Note that we're talking about run-time, not debug-time. Lack of
1038 #       unwind information makes debugging hard on both Windows and
1039 #       Unix. "Unlike" referes to the fact that on Unix signal handler
1040 #       will always be invoked, core dumped and appropriate exit code
1041 #       returned to parent (for user notification).