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format: Emit REP/REPNZ only for string instruction

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This commit is contained in:
Alexis Engelke
2021-01-23 14:29:29 +01:00
parent fe68dbb743
commit 7919b8115a
2 changed files with 12 additions and 7 deletions
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17
format.c
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@@ -122,15 +122,9 @@ fd_format_abs(const FdInstr* instr, uint64_t addr, char* buffer, size_t len)
char* buf = buffer;
char* end = buffer + len;
if (FD_HAS_REP(instr))
buf = fd_strplcpy(buf, "rep ", end-buf);
if (FD_HAS_REPNZ(instr))
buf = fd_strplcpy(buf, "repnz ", end-buf);
if (FD_HAS_LOCK(instr))
buf = fd_strplcpy(buf, "lock ", end-buf);
const char* mnemonic = fdi_name(FD_TYPE(instr));
bool prefix_rep = false;
bool prefix_addrsize = false;
bool prefix_segment = false;
@@ -218,10 +212,19 @@ fd_format_abs(const FdInstr* instr, uint64_t addr, char* buffer, size_t len)
case FDI_SCAS:
case FDI_INS:
prefix_addrsize = true;
prefix_rep = true;
break;
default: break;
}
if (prefix_rep) {
if (FD_HAS_REP(instr))
buf = fd_strplcpy(buf, "rep ", end-buf);
if (FD_HAS_REPNZ(instr))
buf = fd_strplcpy(buf, "repnz ", end-buf);
}
if (FD_HAS_LOCK(instr))
buf = fd_strplcpy(buf, "lock ", end-buf);
if (prefix_addrsize) {
if (FD_IS64(instr) && FD_ADDRSIZE(instr) == 4)
buf = fd_strplcpy(buf, "addr32 ", end-buf);

2
tests/test_decode.c
View File

@@ -100,6 +100,8 @@ main(int argc, char** argv)
TEST64("\x66\x48\x0F\x01\xE2", "smsw rdx");
TEST32("\x66\x0f\x20\x00", "mov eax, cr0"); // mod=0, 66h
TEST64("\x66\x0f\x20\x00", "mov rax, cr0"); // mod=0, 66h
TEST32("\xf3\x0f\x20\x00", "mov eax, cr0"); // REP
TEST64("\xf3\x0f\x20\x00", "mov rax, cr0"); // REP
TEST("\x0f\x20\xc8", "UD"); // cr1
TEST32("\x0f\x20\xd0", "mov eax, cr2"); // cr2
TEST64("\x0f\x20\xd0", "mov rax, cr2"); // cr2