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decode: Change imm_control to get rid of imm_byte

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This commit is contained in:
Alexis Engelke
2020-06-18 17:42:54 +02:00
parent ab5e0c67c1
commit 807d8a817b
2 changed files with 26 additions and 19 deletions
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21
decode.c
View File

@@ -307,7 +307,6 @@ struct InstrDesc
#define DESC_IMPLICIT_IDX(desc) ((((desc)->operand_indices >> 6) & 3) ^ 3)
#define DESC_IMM_CONTROL(desc) (((desc)->immediate >> 4) & 0x7)
#define DESC_IMM_IDX(desc) (((desc)->immediate & 3) ^ 3)
#define DESC_IMM_BYTE(desc) (((desc)->immediate >> 7) & 1)
#define DESC_IMPLICIT_VAL(desc) (((desc)->immediate >> 2) & 1)
int
@@ -500,14 +499,16 @@ fd_decode(const uint8_t* buffer, size_t len_sz, int mode_int, uintptr_t address,
}
uint32_t imm_control = DESC_IMM_CONTROL(desc);
if (imm_control == 1)
if (UNLIKELY(imm_control == 1))
{
// 1 = immediate constant 1, used for shifts
FdOp* operand = &instr->operands[DESC_IMM_IDX(desc)];
operand->type = FD_OT_IMM;
instr->imm = 1;
}
else if (imm_control == 2)
else if (UNLIKELY(imm_control == 2))
{
// 2 = memory, address-sized, used for mov with moffs operand
FdOp* operand = &instr->operands[DESC_IMM_IDX(desc)];
operand->type = FD_OT_MEM;
operand->reg = FD_REG_NONE;
@@ -527,8 +528,9 @@ fd_decode(const uint8_t* buffer, size_t len_sz, int mode_int, uintptr_t address,
#endif
off += addr_size;
}
else if (UNLIKELY(imm_control == 5))
else if (UNLIKELY(imm_control == 3))
{
// 3 = register in imm8[7:4], used for RVMR encoding with VBLENDVP[SD]
FdOp* operand = &instr->operands[DESC_IMM_IDX(desc)];
operand->type = FD_OT_REG;
@@ -546,15 +548,20 @@ fd_decode(const uint8_t* buffer, size_t len_sz, int mode_int, uintptr_t address,
FdOp* operand = &instr->operands[DESC_IMM_IDX(desc)];
operand->type = FD_OT_IMM;
// 4/5 = immediate, operand-sized/8 bit
// 6/7 = offset, operand-sized/8 bit (used for jumps/calls)
int imm_byte = imm_control & 1;
int imm_offset = imm_control & 2;
uint8_t imm_size;
if (DESC_IMM_BYTE(desc))
if (imm_byte)
imm_size = 1;
else if (UNLIKELY(instr->type == FDI_RET || instr->type == FDI_RETF))
imm_size = 2;
else if (UNLIKELY(instr->type == FDI_ENTER))
imm_size = 3;
#if defined(ARCH_X86_64)
else if (mode == DECODE_64 && UNLIKELY(imm_control == 4))
else if (mode == DECODE_64 && UNLIKELY(imm_offset))
// Jumps are always 8 or 32 bit on x86-64.
imm_size = 4;
#endif
@@ -585,7 +592,7 @@ fd_decode(const uint8_t* buffer, size_t len_sz, int mode_int, uintptr_t address,
#endif
off += imm_size;
if (imm_control == 4)
if (imm_offset)
{
if (instr->address != 0)
instr->imm += instr->address + off;

24
parseinstrs.py
View File

@@ -38,7 +38,7 @@ InstrFlags = bitstruct("InstrFlags", [
"zeroreg_val:1",
"_unused:1",
"imm_control:3",
"imm_byte:1",
"_unused:1",
"gp_size_8:1",
"gp_size_def64:1",
"gp_instr_width:1",
@@ -55,30 +55,30 @@ ENCODINGS = {
"NP": InstrFlags(),
"M": InstrFlags(modrm_idx=0^3),
"M1": InstrFlags(modrm_idx=0^3, imm_idx=1^3, imm_control=1),
"MI": InstrFlags(modrm_idx=0^3, imm_idx=1^3, imm_control=3),
"MI": InstrFlags(modrm_idx=0^3, imm_idx=1^3, imm_control=4),
"MC": InstrFlags(modrm_idx=0^3, zeroreg_idx=1^3, zeroreg_val=1),
"MR": InstrFlags(modrm_idx=0^3, modreg_idx=1^3),
"RM": InstrFlags(modrm_idx=1^3, modreg_idx=0^3),
"RMA": InstrFlags(modrm_idx=1^3, modreg_idx=0^3, zeroreg_idx=2^3),
"MRI": InstrFlags(modrm_idx=0^3, modreg_idx=1^3, imm_idx=2^3, imm_control=3),
"RMI": InstrFlags(modrm_idx=1^3, modreg_idx=0^3, imm_idx=2^3, imm_control=3),
"MRI": InstrFlags(modrm_idx=0^3, modreg_idx=1^3, imm_idx=2^3, imm_control=4),
"RMI": InstrFlags(modrm_idx=1^3, modreg_idx=0^3, imm_idx=2^3, imm_control=4),
"MRC": InstrFlags(modrm_idx=0^3, modreg_idx=1^3, zeroreg_idx=2^3, zeroreg_val=1),
"I": InstrFlags(imm_idx=0^3, imm_control=3),
"IA": InstrFlags(zeroreg_idx=0^3, imm_idx=1^3, imm_control=3),
"I": InstrFlags(imm_idx=0^3, imm_control=4),
"IA": InstrFlags(zeroreg_idx=0^3, imm_idx=1^3, imm_control=4),
"O": InstrFlags(modreg_idx=0^3),
"OI": InstrFlags(modreg_idx=0^3, imm_idx=1^3, imm_control=3),
"OI": InstrFlags(modreg_idx=0^3, imm_idx=1^3, imm_control=4),
"OA": InstrFlags(modreg_idx=0^3, zeroreg_idx=1^3),
"AO": InstrFlags(modreg_idx=1^3, zeroreg_idx=0^3),
"D": InstrFlags(imm_idx=0^3, imm_control=4),
"D": InstrFlags(imm_idx=0^3, imm_control=6),
"FD": InstrFlags(zeroreg_idx=0^3, imm_idx=1^3, imm_control=2),
"TD": InstrFlags(zeroreg_idx=1^3, imm_idx=0^3, imm_control=2),
"RVM": InstrFlags(modrm_idx=2^3, modreg_idx=0^3, vexreg_idx=1^3),
"RVMI": InstrFlags(modrm_idx=2^3, modreg_idx=0^3, vexreg_idx=1^3, imm_idx=3^3, imm_control=3, imm_byte=1),
"RVMR": InstrFlags(modrm_idx=2^3, modreg_idx=0^3, vexreg_idx=1^3, imm_idx=3^3, imm_control=5, imm_byte=1),
"RVMI": InstrFlags(modrm_idx=2^3, modreg_idx=0^3, vexreg_idx=1^3, imm_idx=3^3, imm_control=4, imm_byte=1),
"RVMR": InstrFlags(modrm_idx=2^3, modreg_idx=0^3, vexreg_idx=1^3, imm_idx=3^3, imm_control=3, imm_byte=1),
"RMV": InstrFlags(modrm_idx=1^3, modreg_idx=0^3, vexreg_idx=2^3),
"VM": InstrFlags(modrm_idx=1^3, vexreg_idx=0^3),
"VMI": InstrFlags(modrm_idx=1^3, vexreg_idx=0^3, imm_idx=2^3, imm_control=3, imm_byte=1),
"VMI": InstrFlags(modrm_idx=1^3, vexreg_idx=0^3, imm_idx=2^3, imm_control=4, imm_byte=1),
"MVR": InstrFlags(modrm_idx=0^3, modreg_idx=2^3, vexreg_idx=1^3),
}
@@ -138,7 +138,7 @@ class InstrDesc(NamedTuple):
if "DEF64" in self.flags: flags.gp_size_def64 = 1
if "SIZE_8" in self.flags: flags.gp_size_8 = 1
if "INSTR_WIDTH" in self.flags: flags.gp_instr_width = 1
if "IMM_8" in self.flags: flags.imm_byte = 1
if "IMM_8" in self.flags: flags.imm_control = {4: 5, 6: 7}[flags.imm_control]
if "LOCK" in self.flags: flags.lock = 1
if "VSIB" in self.flags: flags.vsib = 1
if "MUSTMEM" in self.flags: setattr(flags, "op%d_regty"%(flags.modrm_idx^3), 0xf)