T0b1/fadec
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

decode: Minor non-functional changes

Browse Source
This commit is contained in:
Alexis Engelke
2020-11-22 15:14:57 +01:00
parent 6fe5500444
commit ad1f1e39c3
3 changed files with 34 additions and 34 deletions
Download Patch File Download Diff File Expand all files Collapse all files

43
decode.c
View File

@@ -85,23 +85,23 @@ decode_prefixes(const uint8_t* buffer, int len, DecodeMode mode,
while (LIKELY(off < len))
{
uint8_t prefix = buffer[off];
switch (prefix)
switch (UNLIKELY(prefix))
{
default: goto out;
// From segment overrides, the last one wins.
case 0x26: *out_segment = FD_REG_ES; off++; break;
case 0x2e: *out_segment = FD_REG_CS; off++; break;
case 0x36: *out_segment = FD_REG_SS; off++; break;
case 0x3e: *out_segment = FD_REG_DS; off++; break;
case 0x64: *out_segment = FD_REG_FS; off++; break;
case 0x65: *out_segment = FD_REG_GS; off++; break;
case 0x67: prefixes |= PREFIX_ADDRSZ; off++; break;
case 0xf0: prefixes |= PREFIX_LOCK; off++; break;
case 0x66: prefixes |= PREFIX_OPSZ; off++; break;
case 0x26: *out_segment = FD_REG_ES; break;
case 0x2e: *out_segment = FD_REG_CS; break;
case 0x36: *out_segment = FD_REG_SS; break;
case 0x3e: *out_segment = FD_REG_DS; break;
case 0x64: *out_segment = FD_REG_FS; break;
case 0x65: *out_segment = FD_REG_GS; break;
case 0x67: prefixes |= PREFIX_ADDRSZ; break;
case 0xf0: prefixes |= PREFIX_LOCK; break;
case 0x66: prefixes |= PREFIX_OPSZ; break;
// From REP/REPE and REPNZ, the last one wins; and for mandatory
// prefixes they have a higher priority than 66h (handled below).
case 0xf3: rep = PREFIX_REP; *out_mandatory = 2; off++; break;
case 0xf2: rep = PREFIX_REPNZ; *out_mandatory = 3; off++; break;
case 0xf3: rep = 2; break;
case 0xf2: rep = 3; break;
#if defined(ARCH_X86_64)
case 0x40: case 0x41: case 0x42: case 0x43: case 0x44: case 0x45:
case 0x46: case 0x47: case 0x48: case 0x49: case 0x4a: case 0x4b:
@@ -114,10 +114,10 @@ decode_prefixes(const uint8_t* buffer, int len, DecodeMode mode,
rex_prefix |= prefix & 0x4 ? PREFIX_REXR : 0;
rex_prefix |= prefix & 0x8 ? PREFIX_REXW : 0;
rex_off = off;
off++;
break;
#endif
}
off++;
}
out:
@@ -128,9 +128,12 @@ out:
// If there is no REP/REPNZ prefix and implied opcode extension from a VEX
// prefix, offer 66h as mandatory prefix. If there is a REP prefix, then the
// 66h prefix is ignored when evaluating mandatory prefixes.
if (*out_mandatory == 0 && (prefixes & PREFIX_OPSZ))
if (rep) {
*out_mandatory = rep;
prefixes |= rep == 3 ? PREFIX_REPNZ : PREFIX_REP;
} else if (prefixes & PREFIX_OPSZ)
*out_mandatory = 1;
*out_prefixes = prefixes | rep;
*out_prefixes = prefixes;
return off;
}
@@ -191,8 +194,7 @@ decode_modrm(const uint8_t* buffer, int len, DecodeMode mode, FdInstr* instr,
uint8_t reg_idx = rm;
#if defined(ARCH_X86_64)
if (!UNLIKELY(out_o1->misc == FD_RT_FPU || out_o1->misc == FD_RT_MMX ||
out_o1->misc == FD_RT_MASK))
if (LIKELY(out_o1->misc == FD_RT_GPL || out_o1->misc == FD_RT_VEC))
reg_idx += prefixes & PREFIX_REXB ? 8 : 0;
#endif
out_o1->type = FD_OT_REG;
@@ -446,7 +448,7 @@ fd_decode(const uint8_t* buffer, size_t len_sz, int mode_int, uintptr_t address,
instr->operands[i].misc = (0xf0857641 >> (4 * reg_type)) & 0xf;
}
if (DESC_HAS_IMPLICIT(desc))
if (UNLIKELY(DESC_HAS_IMPLICIT(desc)))
{
FdOp* operand = &instr->operands[DESC_IMPLICIT_IDX(desc)];
operand->type = FD_OT_REG;
@@ -471,10 +473,9 @@ fd_decode(const uint8_t* buffer, size_t len_sz, int mode_int, uintptr_t address,
// If there is no ModRM, but a Mod-Reg, its opcode-encoded.
FdOp* operand = &instr->operands[DESC_MODREG_IDX(desc)];
uint8_t reg_idx = buffer[off - 1] & 7;
// FIXME: don't apply REX.B to FPU, MMX, and MASK registers.
#if defined(ARCH_X86_64)
if (!UNLIKELY(operand->misc == FD_RT_FPU))
reg_idx += prefixes & PREFIX_REXB ? 8 : 0;
// Only used for GP registers, therefore always apply REX.B.
reg_idx += prefixes & PREFIX_REXB ? 8 : 0;
#endif
operand->type = FD_OT_REG;
operand->reg = reg_idx;