diff options
Diffstat (limited to 'src/lib/libcrypto/perlasm')
-rwxr-xr-x | src/lib/libcrypto/perlasm/x86_64-xlate.pl | 554 |
1 files changed, 554 insertions, 0 deletions
diff --git a/src/lib/libcrypto/perlasm/x86_64-xlate.pl b/src/lib/libcrypto/perlasm/x86_64-xlate.pl new file mode 100755 index 0000000000..a4af769b4a --- /dev/null +++ b/src/lib/libcrypto/perlasm/x86_64-xlate.pl | |||
@@ -0,0 +1,554 @@ | |||
1 | #!/usr/bin/env perl | ||
2 | |||
3 | # Ascetic x86_64 AT&T to MASM 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 | # - indirect calls and jumps are not supported; | ||
24 | # | ||
25 | # Dual-ABI styling rules. | ||
26 | # | ||
27 | # 1. Adhere to Unix register and stack layout [see the end for | ||
28 | # explanation]. | ||
29 | # 2. Forget about "red zone," stick to more traditional blended | ||
30 | # stack frame allocation. If volatile storage is actually required | ||
31 | # that is. If not, just leave the stack as is. | ||
32 | # 3. Functions tagged with ".type name,@function" get crafted with | ||
33 | # unified Win64 prologue and epilogue automatically. If you want | ||
34 | # to take care of ABI differences yourself, tag functions as | ||
35 | # ".type name,@abi-omnipotent" instead. | ||
36 | # 4. To optimize the Win64 prologue you can specify number of input | ||
37 | # arguments as ".type name,@function,N." Keep in mind that if N is | ||
38 | # larger than 6, then you *have to* write "abi-omnipotent" code, | ||
39 | # because >6 cases can't be addressed with unified prologue. | ||
40 | # 5. Name local labels as .L*, do *not* use dynamic labels such as 1: | ||
41 | # (sorry about latter). | ||
42 | # 6. Don't use [or hand-code with .byte] "rep ret." "ret" mnemonic is | ||
43 | # required to identify the spots, where to inject Win64 epilogue! | ||
44 | # But on the pros, it's then prefixed with rep automatically:-) | ||
45 | # 7. Due to MASM limitations [and certain general counter-intuitivity | ||
46 | # of ip-relative addressing] generation of position-independent | ||
47 | # code is assisted by synthetic directive, .picmeup, which puts | ||
48 | # address of the *next* instruction into target register. | ||
49 | # | ||
50 | # Example 1: | ||
51 | # .picmeup %rax | ||
52 | # lea .Label-.(%rax),%rax | ||
53 | # Example 2: | ||
54 | # .picmeup %rcx | ||
55 | # .Lpic_point: | ||
56 | # ... | ||
57 | # lea .Label-.Lpic_point(%rcx),%rbp | ||
58 | |||
59 | my $output = shift; | ||
60 | |||
61 | { my ($stddev,$stdino,@junk)=stat(STDOUT); | ||
62 | my ($outdev,$outino,@junk)=stat($output); | ||
63 | |||
64 | open STDOUT,">$output" || die "can't open $output: $!" | ||
65 | if ($stddev!=$outdev || $stdino!=$outino); | ||
66 | } | ||
67 | |||
68 | my $masmref=8 + 50727*2**-32; # 8.00.50727 shipped with VS2005 | ||
69 | my $masm=$masmref if ($output =~ /\.asm/); | ||
70 | if ($masm && `ml64 2>&1` =~ m/Version ([0-9]+)\.([0-9]+)(\.([0-9]+))?/) | ||
71 | { $masm=$1 + $2*2**-16 + $4*2**-32; } | ||
72 | |||
73 | my $current_segment; | ||
74 | my $current_function; | ||
75 | |||
76 | { package opcode; # pick up opcodes | ||
77 | sub re { | ||
78 | my $self = shift; # single instance in enough... | ||
79 | local *line = shift; | ||
80 | undef $ret; | ||
81 | |||
82 | if ($line =~ /^([a-z][a-z0-9]*)/i) { | ||
83 | $self->{op} = $1; | ||
84 | $ret = $self; | ||
85 | $line = substr($line,@+[0]); $line =~ s/^\s+//; | ||
86 | |||
87 | undef $self->{sz}; | ||
88 | if ($self->{op} =~ /^(movz)b.*/) { # movz is pain... | ||
89 | $self->{op} = $1; | ||
90 | $self->{sz} = "b"; | ||
91 | } elsif ($self->{op} =~ /call/) { | ||
92 | $self->{sz} = "" | ||
93 | } elsif ($self->{op} =~ /([a-z]{3,})([qlwb])$/) { | ||
94 | $self->{op} = $1; | ||
95 | $self->{sz} = $2; | ||
96 | } | ||
97 | } | ||
98 | $ret; | ||
99 | } | ||
100 | sub size { | ||
101 | my $self = shift; | ||
102 | my $sz = shift; | ||
103 | $self->{sz} = $sz if (defined($sz) && !defined($self->{sz})); | ||
104 | $self->{sz}; | ||
105 | } | ||
106 | sub out { | ||
107 | my $self = shift; | ||
108 | if (!$masm) { | ||
109 | if ($self->{op} eq "movz") { # movz is pain... | ||
110 | sprintf "%s%s%s",$self->{op},$self->{sz},shift; | ||
111 | } elsif ($self->{op} =~ /^set/) { | ||
112 | "$self->{op}"; | ||
113 | } elsif ($self->{op} eq "ret") { | ||
114 | ".byte 0xf3,0xc3"; | ||
115 | } else { | ||
116 | "$self->{op}$self->{sz}"; | ||
117 | } | ||
118 | } else { | ||
119 | $self->{op} =~ s/^movz/movzx/; | ||
120 | if ($self->{op} eq "ret") { | ||
121 | $self->{op} = ""; | ||
122 | if ($current_function->{abi} eq "svr4") { | ||
123 | $self->{op} = "mov rdi,QWORD PTR 8[rsp]\t;WIN64 epilogue\n\t". | ||
124 | "mov rsi,QWORD PTR 16[rsp]\n\t"; | ||
125 | } | ||
126 | $self->{op} .= "DB\t0F3h,0C3h\t\t;repret"; | ||
127 | } | ||
128 | $self->{op}; | ||
129 | } | ||
130 | } | ||
131 | } | ||
132 | { package const; # pick up constants, which start with $ | ||
133 | sub re { | ||
134 | my $self = shift; # single instance in enough... | ||
135 | local *line = shift; | ||
136 | undef $ret; | ||
137 | |||
138 | if ($line =~ /^\$([^,]+)/) { | ||
139 | $self->{value} = $1; | ||
140 | $ret = $self; | ||
141 | $line = substr($line,@+[0]); $line =~ s/^\s+//; | ||
142 | } | ||
143 | $ret; | ||
144 | } | ||
145 | sub out { | ||
146 | my $self = shift; | ||
147 | |||
148 | if (!$masm) { | ||
149 | # Solaris /usr/ccs/bin/as can't handle multiplications | ||
150 | # in $self->{value} | ||
151 | $self->{value} =~ s/(?<![0-9a-f])(0[x0-9a-f]+)/oct($1)/egi; | ||
152 | $self->{value} =~ s/([0-9]+\s*[\*\/\%]\s*[0-9]+)/eval($1)/eg; | ||
153 | sprintf "\$%s",$self->{value}; | ||
154 | } else { | ||
155 | $self->{value} =~ s/0x([0-9a-f]+)/0$1h/ig; | ||
156 | sprintf "%s",$self->{value}; | ||
157 | } | ||
158 | } | ||
159 | } | ||
160 | { package ea; # pick up effective addresses: expr(%reg,%reg,scale) | ||
161 | sub re { | ||
162 | my $self = shift; # single instance in enough... | ||
163 | local *line = shift; | ||
164 | undef $ret; | ||
165 | |||
166 | if ($line =~ /^([^\(,]*)\(([%\w,]+)\)/) { | ||
167 | $self->{label} = $1; | ||
168 | ($self->{base},$self->{index},$self->{scale})=split(/,/,$2); | ||
169 | $self->{scale} = 1 if (!defined($self->{scale})); | ||
170 | $ret = $self; | ||
171 | $line = substr($line,@+[0]); $line =~ s/^\s+//; | ||
172 | |||
173 | $self->{base} =~ s/^%//; | ||
174 | $self->{index} =~ s/^%// if (defined($self->{index})); | ||
175 | } | ||
176 | $ret; | ||
177 | } | ||
178 | sub size {} | ||
179 | sub out { | ||
180 | my $self = shift; | ||
181 | my $sz = shift; | ||
182 | |||
183 | # Silently convert all EAs to 64-bit. This is required for | ||
184 | # elder GNU assembler and results in more compact code, | ||
185 | # *but* most importantly AES module depends on this feature! | ||
186 | $self->{index} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/; | ||
187 | $self->{base} =~ s/^[er](.?[0-9xpi])[d]?$/r\1/; | ||
188 | |||
189 | if (!$masm) { | ||
190 | # Solaris /usr/ccs/bin/as can't handle multiplications | ||
191 | # in $self->{label} | ||
192 | $self->{label} =~ s/(?<![0-9a-f])(0[x0-9a-f]+)/oct($1)/egi; | ||
193 | $self->{label} =~ s/([0-9]+\s*[\*\/\%]\s*[0-9]+)/eval($1)/eg; | ||
194 | |||
195 | if (defined($self->{index})) { | ||
196 | sprintf "%s(%%%s,%%%s,%d)", | ||
197 | $self->{label},$self->{base}, | ||
198 | $self->{index},$self->{scale}; | ||
199 | } else { | ||
200 | sprintf "%s(%%%s)", $self->{label},$self->{base}; | ||
201 | } | ||
202 | } else { | ||
203 | %szmap = ( b=>"BYTE", w=>"WORD", l=>"DWORD", q=>"QWORD" ); | ||
204 | |||
205 | $self->{label} =~ s/\./\$/g; | ||
206 | $self->{label} =~ s/0x([0-9a-f]+)/0$1h/ig; | ||
207 | $self->{label} = "($self->{label})" if ($self->{label} =~ /[\*\+\-\/]/); | ||
208 | |||
209 | if (defined($self->{index})) { | ||
210 | sprintf "%s PTR %s[%s*%d+%s]",$szmap{$sz}, | ||
211 | $self->{label}, | ||
212 | $self->{index},$self->{scale}, | ||
213 | $self->{base}; | ||
214 | } elsif ($self->{base} eq "rip") { | ||
215 | sprintf "%s PTR %s",$szmap{$sz},$self->{label}; | ||
216 | } else { | ||
217 | sprintf "%s PTR %s[%s]",$szmap{$sz}, | ||
218 | $self->{label},$self->{base}; | ||
219 | } | ||
220 | } | ||
221 | } | ||
222 | } | ||
223 | { package register; # pick up registers, which start with %. | ||
224 | sub re { | ||
225 | my $class = shift; # muliple instances... | ||
226 | my $self = {}; | ||
227 | local *line = shift; | ||
228 | undef $ret; | ||
229 | |||
230 | if ($line =~ /^%(\w+)/) { | ||
231 | bless $self,$class; | ||
232 | $self->{value} = $1; | ||
233 | $ret = $self; | ||
234 | $line = substr($line,@+[0]); $line =~ s/^\s+//; | ||
235 | } | ||
236 | $ret; | ||
237 | } | ||
238 | sub size { | ||
239 | my $self = shift; | ||
240 | undef $ret; | ||
241 | |||
242 | if ($self->{value} =~ /^r[\d]+b$/i) { $ret="b"; } | ||
243 | elsif ($self->{value} =~ /^r[\d]+w$/i) { $ret="w"; } | ||
244 | elsif ($self->{value} =~ /^r[\d]+d$/i) { $ret="l"; } | ||
245 | elsif ($self->{value} =~ /^r[\w]+$/i) { $ret="q"; } | ||
246 | elsif ($self->{value} =~ /^[a-d][hl]$/i){ $ret="b"; } | ||
247 | elsif ($self->{value} =~ /^[\w]{2}l$/i) { $ret="b"; } | ||
248 | elsif ($self->{value} =~ /^[\w]{2}$/i) { $ret="w"; } | ||
249 | elsif ($self->{value} =~ /^e[a-z]{2}$/i){ $ret="l"; } | ||
250 | |||
251 | $ret; | ||
252 | } | ||
253 | sub out { | ||
254 | my $self = shift; | ||
255 | sprintf $masm?"%s":"%%%s",$self->{value}; | ||
256 | } | ||
257 | } | ||
258 | { package label; # pick up labels, which end with : | ||
259 | sub re { | ||
260 | my $self = shift; # single instance is enough... | ||
261 | local *line = shift; | ||
262 | undef $ret; | ||
263 | |||
264 | if ($line =~ /(^[\.\w]+\:)/) { | ||
265 | $self->{value} = $1; | ||
266 | $ret = $self; | ||
267 | $line = substr($line,@+[0]); $line =~ s/^\s+//; | ||
268 | |||
269 | $self->{value} =~ s/\.L/\$L/ if ($masm); | ||
270 | } | ||
271 | $ret; | ||
272 | } | ||
273 | sub out { | ||
274 | my $self = shift; | ||
275 | |||
276 | if (!$masm) { | ||
277 | $self->{value}; | ||
278 | } elsif ($self->{value} ne "$current_function->{name}:") { | ||
279 | $self->{value}; | ||
280 | } elsif ($current_function->{abi} eq "svr4") { | ||
281 | my $func = "$current_function->{name} PROC\n". | ||
282 | " mov QWORD PTR 8[rsp],rdi\t;WIN64 prologue\n". | ||
283 | " mov QWORD PTR 16[rsp],rsi\n"; | ||
284 | my $narg = $current_function->{narg}; | ||
285 | $narg=6 if (!defined($narg)); | ||
286 | $func .= " mov rdi,rcx\n" if ($narg>0); | ||
287 | $func .= " mov rsi,rdx\n" if ($narg>1); | ||
288 | $func .= " mov rdx,r8\n" if ($narg>2); | ||
289 | $func .= " mov rcx,r9\n" if ($narg>3); | ||
290 | $func .= " mov r8,QWORD PTR 40[rsp]\n" if ($narg>4); | ||
291 | $func .= " mov r9,QWORD PTR 48[rsp]\n" if ($narg>5); | ||
292 | $func .= "\n"; | ||
293 | } else { | ||
294 | "$current_function->{name} PROC"; | ||
295 | } | ||
296 | } | ||
297 | } | ||
298 | { package expr; # pick up expressioins | ||
299 | sub re { | ||
300 | my $self = shift; # single instance is enough... | ||
301 | local *line = shift; | ||
302 | undef $ret; | ||
303 | |||
304 | if ($line =~ /(^[^,]+)/) { | ||
305 | $self->{value} = $1; | ||
306 | $ret = $self; | ||
307 | $line = substr($line,@+[0]); $line =~ s/^\s+//; | ||
308 | |||
309 | $self->{value} =~ s/\.L/\$L/g if ($masm); | ||
310 | } | ||
311 | $ret; | ||
312 | } | ||
313 | sub out { | ||
314 | my $self = shift; | ||
315 | $self->{value}; | ||
316 | } | ||
317 | } | ||
318 | { package directive; # pick up directives, which start with . | ||
319 | sub re { | ||
320 | my $self = shift; # single instance is enough... | ||
321 | local *line = shift; | ||
322 | undef $ret; | ||
323 | my $dir; | ||
324 | my %opcode = # lea 2f-1f(%rip),%dst; 1: nop; 2: | ||
325 | ( "%rax"=>0x01058d48, "%rcx"=>0x010d8d48, | ||
326 | "%rdx"=>0x01158d48, "%rbx"=>0x011d8d48, | ||
327 | "%rsp"=>0x01258d48, "%rbp"=>0x012d8d48, | ||
328 | "%rsi"=>0x01358d48, "%rdi"=>0x013d8d48, | ||
329 | "%r8" =>0x01058d4c, "%r9" =>0x010d8d4c, | ||
330 | "%r10"=>0x01158d4c, "%r11"=>0x011d8d4c, | ||
331 | "%r12"=>0x01258d4c, "%r13"=>0x012d8d4c, | ||
332 | "%r14"=>0x01358d4c, "%r15"=>0x013d8d4c ); | ||
333 | |||
334 | if ($line =~ /^\s*(\.\w+)/) { | ||
335 | if (!$masm) { | ||
336 | $self->{value} = $1; | ||
337 | $line =~ s/\@abi\-omnipotent/\@function/; | ||
338 | $line =~ s/\@function.*/\@function/; | ||
339 | if ($line =~ /\.picmeup\s+(%r[\w]+)/i) { | ||
340 | $self->{value} = sprintf "\t.long\t0x%x,0x90000000",$opcode{$1}; | ||
341 | } elsif ($line =~ /\.asciz\s+"(.*)"$/) { | ||
342 | $self->{value} = ".byte\t".join(",",unpack("C*",$1),0); | ||
343 | } elsif ($line =~ /\.extern/) { | ||
344 | $self->{value} = ""; # swallow extern | ||
345 | } else { | ||
346 | $self->{value} = $line; | ||
347 | } | ||
348 | $line = ""; | ||
349 | return $self; | ||
350 | } | ||
351 | |||
352 | $dir = $1; | ||
353 | $ret = $self; | ||
354 | undef $self->{value}; | ||
355 | $line = substr($line,@+[0]); $line =~ s/^\s+//; | ||
356 | SWITCH: for ($dir) { | ||
357 | /\.(text)/ | ||
358 | && do { my $v=undef; | ||
359 | $v="$current_segment\tENDS\n" if ($current_segment); | ||
360 | $current_segment = "_$1\$"; | ||
361 | $current_segment =~ tr/[a-z]/[A-Z]/; | ||
362 | $v.="$current_segment\tSEGMENT "; | ||
363 | $v.=$masm>=$masmref ? "ALIGN(64)" : "PAGE"; | ||
364 | $v.=" 'CODE'"; | ||
365 | $self->{value} = $v; | ||
366 | last; | ||
367 | }; | ||
368 | /\.extern/ && do { $self->{value} = "EXTRN\t".$line.":BYTE"; last; }; | ||
369 | /\.globl/ && do { $self->{value} = "PUBLIC\t".$line; last; }; | ||
370 | /\.type/ && do { ($sym,$type,$narg) = split(',',$line); | ||
371 | if ($type eq "\@function") { | ||
372 | undef $current_function; | ||
373 | $current_function->{name} = $sym; | ||
374 | $current_function->{abi} = "svr4"; | ||
375 | $current_function->{narg} = $narg; | ||
376 | } elsif ($type eq "\@abi-omnipotent") { | ||
377 | undef $current_function; | ||
378 | $current_function->{name} = $sym; | ||
379 | } | ||
380 | last; | ||
381 | }; | ||
382 | /\.size/ && do { if (defined($current_function)) { | ||
383 | $self->{value}="$current_function->{name}\tENDP"; | ||
384 | undef $current_function; | ||
385 | } | ||
386 | last; | ||
387 | }; | ||
388 | /\.align/ && do { $self->{value} = "ALIGN\t".$line; last; }; | ||
389 | /\.(byte|value|long|quad)/ | ||
390 | && do { my @arr = split(',',$line); | ||
391 | my $sz = substr($1,0,1); | ||
392 | my $last = pop(@arr); | ||
393 | my $conv = sub { my $var=shift; | ||
394 | if ($var=~s/0x([0-9a-f]+)/0$1h/i) { $var; } | ||
395 | else { sprintf"0%Xh",$var; } | ||
396 | }; | ||
397 | |||
398 | $sz =~ tr/bvlq/BWDQ/; | ||
399 | $self->{value} = "\tD$sz\t"; | ||
400 | for (@arr) { $self->{value} .= &$conv($_).","; } | ||
401 | $self->{value} .= &$conv($last); | ||
402 | last; | ||
403 | }; | ||
404 | /\.picmeup/ && do { $self->{value} = sprintf"\tDD\t 0%Xh,090000000h",$opcode{$line}; | ||
405 | last; | ||
406 | }; | ||
407 | /\.asciz/ && do { if ($line =~ /^"(.*)"$/) { | ||
408 | my @str=unpack("C*",$1); | ||
409 | push @str,0; | ||
410 | while ($#str>15) { | ||
411 | $self->{value}.="DB\t" | ||
412 | .join(",",@str[0..15])."\n"; | ||
413 | foreach (0..15) { shift @str; } | ||
414 | } | ||
415 | $self->{value}.="DB\t" | ||
416 | .join(",",@str) if (@str); | ||
417 | } | ||
418 | last; | ||
419 | }; | ||
420 | } | ||
421 | $line = ""; | ||
422 | } | ||
423 | |||
424 | $ret; | ||
425 | } | ||
426 | sub out { | ||
427 | my $self = shift; | ||
428 | $self->{value}; | ||
429 | } | ||
430 | } | ||
431 | |||
432 | while($line=<>) { | ||
433 | |||
434 | chomp($line); | ||
435 | |||
436 | $line =~ s|[#!].*$||; # get rid of asm-style comments... | ||
437 | $line =~ s|/\*.*\*/||; # ... and C-style comments... | ||
438 | $line =~ s|^\s+||; # ... and skip white spaces in beginning | ||
439 | |||
440 | undef $label; | ||
441 | undef $opcode; | ||
442 | undef $dst; | ||
443 | undef $src; | ||
444 | undef $sz; | ||
445 | |||
446 | if ($label=label->re(\$line)) { print $label->out(); } | ||
447 | |||
448 | if (directive->re(\$line)) { | ||
449 | printf "%s",directive->out(); | ||
450 | } elsif ($opcode=opcode->re(\$line)) { ARGUMENT: { | ||
451 | |||
452 | if ($src=register->re(\$line)) { opcode->size($src->size()); } | ||
453 | elsif ($src=const->re(\$line)) { } | ||
454 | elsif ($src=ea->re(\$line)) { } | ||
455 | elsif ($src=expr->re(\$line)) { } | ||
456 | |||
457 | last ARGUMENT if ($line !~ /^,/); | ||
458 | |||
459 | $line = substr($line,1); $line =~ s/^\s+//; | ||
460 | |||
461 | if ($dst=register->re(\$line)) { opcode->size($dst->size()); } | ||
462 | elsif ($dst=const->re(\$line)) { } | ||
463 | elsif ($dst=ea->re(\$line)) { } | ||
464 | |||
465 | } # ARGUMENT: | ||
466 | |||
467 | $sz=opcode->size(); | ||
468 | |||
469 | if (defined($dst)) { | ||
470 | if (!$masm) { | ||
471 | printf "\t%s\t%s,%s", $opcode->out($dst->size()), | ||
472 | $src->out($sz),$dst->out($sz); | ||
473 | } else { | ||
474 | printf "\t%s\t%s,%s", $opcode->out(), | ||
475 | $dst->out($sz),$src->out($sz); | ||
476 | } | ||
477 | } elsif (defined($src)) { | ||
478 | printf "\t%s\t%s",$opcode->out(),$src->out($sz); | ||
479 | } else { | ||
480 | printf "\t%s",$opcode->out(); | ||
481 | } | ||
482 | } | ||
483 | |||
484 | print $line,"\n"; | ||
485 | } | ||
486 | |||
487 | print "\n$current_segment\tENDS\nEND\n" if ($masm); | ||
488 | |||
489 | close STDOUT; | ||
490 | |||
491 | ################################################# | ||
492 | # Cross-reference x86_64 ABI "card" | ||
493 | # | ||
494 | # Unix Win64 | ||
495 | # %rax * * | ||
496 | # %rbx - - | ||
497 | # %rcx #4 #1 | ||
498 | # %rdx #3 #2 | ||
499 | # %rsi #2 - | ||
500 | # %rdi #1 - | ||
501 | # %rbp - - | ||
502 | # %rsp - - | ||
503 | # %r8 #5 #3 | ||
504 | # %r9 #6 #4 | ||
505 | # %r10 * * | ||
506 | # %r11 * * | ||
507 | # %r12 - - | ||
508 | # %r13 - - | ||
509 | # %r14 - - | ||
510 | # %r15 - - | ||
511 | # | ||
512 | # (*) volatile register | ||
513 | # (-) preserved by callee | ||
514 | # (#) Nth argument, volatile | ||
515 | # | ||
516 | # In Unix terms top of stack is argument transfer area for arguments | ||
517 | # which could not be accomodated in registers. Or in other words 7th | ||
518 | # [integer] argument resides at 8(%rsp) upon function entry point. | ||
519 | # 128 bytes above %rsp constitute a "red zone" which is not touched | ||
520 | # by signal handlers and can be used as temporal storage without | ||
521 | # allocating a frame. | ||
522 | # | ||
523 | # In Win64 terms N*8 bytes on top of stack is argument transfer area, | ||
524 | # which belongs to/can be overwritten by callee. N is the number of | ||
525 | # arguments passed to callee, *but* not less than 4! This means that | ||
526 | # upon function entry point 5th argument resides at 40(%rsp), as well | ||
527 | # as that 32 bytes from 8(%rsp) can always be used as temporal | ||
528 | # storage [without allocating a frame]. One can actually argue that | ||
529 | # one can assume a "red zone" above stack pointer under Win64 as well. | ||
530 | # Point is that at apparently no occasion Windows kernel would alter | ||
531 | # the area above user stack pointer in true asynchronous manner... | ||
532 | # | ||
533 | # All the above means that if assembler programmer adheres to Unix | ||
534 | # register and stack layout, but disregards the "red zone" existense, | ||
535 | # it's possible to use following prologue and epilogue to "gear" from | ||
536 | # Unix to Win64 ABI in leaf functions with not more than 6 arguments. | ||
537 | # | ||
538 | # omnipotent_function: | ||
539 | # ifdef WIN64 | ||
540 | # movq %rdi,8(%rsp) | ||
541 | # movq %rsi,16(%rsp) | ||
542 | # movq %rcx,%rdi ; if 1st argument is actually present | ||
543 | # movq %rdx,%rsi ; if 2nd argument is actually ... | ||
544 | # movq %r8,%rdx ; if 3rd argument is ... | ||
545 | # movq %r9,%rcx ; if 4th argument ... | ||
546 | # movq 40(%rsp),%r8 ; if 5th ... | ||
547 | # movq 48(%rsp),%r9 ; if 6th ... | ||
548 | # endif | ||
549 | # ... | ||
550 | # ifdef WIN64 | ||
551 | # movq 8(%rsp),%rdi | ||
552 | # movq 16(%rsp),%rsi | ||
553 | # endif | ||
554 | # ret | ||