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decode: Store operand size logarithmic

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This commit is contained in:
Alexis Engelke
2022-11-25 13:17:40 +01:00
parent 1291603246
commit b817713ae8
2 changed files with 22 additions and 21 deletions
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37
decode.c
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@@ -120,7 +120,7 @@ fd_decode(const uint8_t* buffer, size_t len_sz, int mode_int, uintptr_t address,
unsigned prefix_rep = 0;
bool prefix_lock = false;
bool prefix_66 = false;
uint8_t addr_size = mode == DECODE_64 ? 8 : 4;
uint8_t addr_size = mode == DECODE_64 ? 3 : 2;
unsigned prefix_rex = 0;
int rex_off = -1;
instr->segment = FD_REG_NONE;
@@ -140,7 +140,7 @@ fd_decode(const uint8_t* buffer, size_t len_sz, int mode_int, uintptr_t address,
case 0x64: instr->segment = FD_REG_FS; break;
case 0x65: instr->segment = FD_REG_GS; break;
case 0x66: prefix_66 = true; break;
case 0x67: addr_size = 2; break;
case 0x67: addr_size = 1; break;
case 0xf0: prefix_lock = true; break;
case 0xf3: prefix_rep = 2; break;
case 0xf2: prefix_rep = 3; break;
@@ -161,7 +161,7 @@ fd_decode(const uint8_t* buffer, size_t len_sz, int mode_int, uintptr_t address,
case 0x64: instr->segment = FD_REG_FS; break;
case 0x65: instr->segment = FD_REG_GS; break;
case 0x66: prefix_66 = true; break;
case 0x67: addr_size = 4; break;
case 0x67: addr_size = 2; break;
case 0xf0: prefix_lock = true; break;
case 0xf3: prefix_rep = 2; break;
case 0xf2: prefix_rep = 3; break;
@@ -292,16 +292,16 @@ prefix_end:
if (DESC_OPSIZE(desc) == 1)
op_size = 1;
else if (mode == DECODE_64)
op_size = ((prefix_rex & PREFIX_REXW) || DESC_OPSIZE(desc) == 3) ? 8 :
op_size = ((prefix_rex & PREFIX_REXW) || DESC_OPSIZE(desc) == 3) ? 4 :
UNLIKELY(prefix_66 && !DESC_IGN66(desc)) ? 2 :
DESC_OPSIZE(desc) ? 8 :
4;
DESC_OPSIZE(desc) ? 4 :
3;
else
op_size = UNLIKELY(prefix_66 && !DESC_IGN66(desc)) ? 2 : 4;
op_size = UNLIKELY(prefix_66 && !DESC_IGN66(desc)) ? 2 : 3;
uint8_t vec_size = 16;
uint8_t vec_size = 5;
if (prefix_rex & PREFIX_VEXL)
vec_size = 32;
vec_size = 6;
for (unsigned i = 0; i < sizeof(instr->operands) / sizeof(FdOp); i++)
instr->operands[i] = (FdOp) {0};
@@ -450,15 +450,16 @@ skip_modrm:
operand->reg = FD_REG_NONE;
operand->misc = FD_REG_NONE;
if (UNLIKELY(off + addr_size > len))
int moffsz = 1 << addr_size;
if (UNLIKELY(off + moffsz > len))
return FD_ERR_PARTIAL;
if (addr_size == 2)
if (moffsz == 2)
instr->disp = LOAD_LE_2(&buffer[off]);
if (addr_size == 4)
if (moffsz == 4)
instr->disp = LOAD_LE_4(&buffer[off]);
if (LIKELY(addr_size == 8))
if (LIKELY(moffsz == 8))
instr->disp = LOAD_LE_8(&buffer[off]);
off += addr_size;
off += moffsz;
}
else if (UNLIKELY(imm_control == 3))
{
@@ -495,11 +496,11 @@ skip_modrm:
instr->type == FDI_SSE_INSERTQ))
imm_size = 2;
else if (UNLIKELY(instr->type == FDI_JMPF || instr->type == FDI_CALLF))
imm_size = op_size + 2;
imm_size = (1 << op_size >> 1) + 2;
else if (UNLIKELY(instr->type == FDI_ENTER))
imm_size = 3;
else if (instr->type == FDI_MOVABS)
imm_size = op_size;
imm_size = (1 << op_size >> 1);
else
imm_size = op_size == 2 ? 2 : 4;
@@ -561,7 +562,7 @@ skip_modrm:
}
uint8_t operand_sizes[4] = {
1 << DESC_SIZE_FIX1(desc) >> 1, 1 << DESC_SIZE_FIX2(desc), op_size, vec_size
DESC_SIZE_FIX1(desc), DESC_SIZE_FIX2(desc) + 1, op_size, vec_size
};
for (int i = 0; i < 4; i++)
@@ -587,7 +588,7 @@ skip_modrm:
}
instr->size = off;
instr->operandsz = DESC_INSTR_WIDTH(desc) ? op_size : 0;
instr->operandsz = DESC_INSTR_WIDTH(desc) ? op_size - 1 : 0;
return off;
}