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Fix register usage conventions for amd64 unfilter

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modified:   stub/src/amd64-win64.pep.S
	modified:   stub/src/arch/amd64/bxx.S
This commit is contained in:
John Reiser 2017-02-05 13:29:59 -08:00
parent f7751684af
commit 71f4cd7c85
2 changed files with 7 additions and 10 deletions
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7
src/stub/src/amd64-win64.pep.S
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@ -234,11 +234,10 @@ section PEFILTER49
mov ecx, offset filter_length
mov dl, IMM8(filter_cto)
.att_syntax
#define esi ebx
#define rsi rbx
push %rsi // save
push %rbx; pop %rsi // input len
#include "arch/amd64/bxx.S"
#undef esi
#undef rsi
pop %rsi // restore
.intel_syntax noprefix
// =============

10
src/stub/src/arch/amd64/bxx.S
View File

@ -35,11 +35,9 @@ amdbxx: # (*f_unf)(xo->buf, out_len, h.b_cto8, h.b_ftid);
#ifndef NO_METHOD_CHECK
cmpl $0x49,ftid; jne ckend0 # filter: JMP, CALL, 6-byte Jxx
#endif
push %rbx # save
cld # convention should have guaranteed this already
push %rdi; lea (1- 4)(%rdi,%rsi),%rcx # beyond last possible opcode
#endif
push %rdi; lea -4(%rdi,%rsi),%rcx # last possible displacement
pop %rsi # start of buffer
push %rsi
pop %rbx # remember start of buffer
@ -56,7 +54,7 @@ ckloop2:
subb $ 0xE8,%al
cmpb $0xE9-0xE8,%al; ja ckloop4 # not JMP, not CALL
ckmark:
cmpq %rcx,%rsi; jae ckend # peek only; not marked ==> do not consume
cmpq %rcx,%rsi; ja ckend # peek only; not marked ==> do not consume
push %rsi; lodsl # (assume) marked, bswapped 32-bit displacement
subb %dl,%al; jne ckloop3 # not marked with cto8
pop %rdi
@ -68,9 +66,9 @@ ckstart:
cmpq %rcx,%rsi; jae ckend
lodsb; jmp ckloop2 # 0x0F prefix would overlap previous displacement
ckend:
#ifndef NO_METHOD_CHECK
pop %rbx # restore
ckend0:
#ifndef NO_METHOD_CHECK
ret
#endif