iced-x86 disassembler Python bindings
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iced-x86 is a high performance and correct x86 (16/32/64-bit) disassembler for Python.
- ✔️Supports all Intel and AMD instructions
- ✔️Correct: All instructions are tested and iced has been tested against other disassemblers/assemblers (xed, gas, objdump, masm, dumpbin, nasm, ndisasm) and fuzzed
- ✔️The formatter supports masm, nasm, gas (AT&T), Intel (XED) and there are many options to customize the output
- ✔️The encoder can be used to re-encode decoded instructions at any address
- ✔️API to get instruction info, eg. read/written registers, memory and rflags bits; CPUID feature flag, control flow info, etc
- ✔️Rust + Python
- ✔️License: MIT
Rust crate: https://github.com/0xd4d/iced/blob/master/src/rust/iced-x86/README.md
Installing iced-x86
It's on PyPI with built wheels for Windows, macOS and Linux so this command should work (use python
or py
if on Windows):
python3 -m pip install iced-x86
If pip
tries to build it from source and fails, see below for all required build tools (eg. python3 -m pip install setuptools wheel setuptools-rust
and Rust https://www.rust-lang.org/tools/install).
Building the code
If on Windows, replace python3
in all commands with python
or py
.
Prerequisites:
# Create the wheel
python3 setup.py bdist_wheel
# Install the built wheel
python3 -m pip install iced-x86 --no-index -f dist
# Uninstall your built copy
python3 -m pip uninstall iced-x86
Prerequisites (tests/docs):
python3 -m pip install -r requirements-dev.txt
Tests:
python3 setup.py bdist_wheel
python3 -m pip install iced-x86 --no-index -f dist
python3 -m pytest
python3 -m pip uninstall -y iced-x86
Docs:
# Need the built module in build/lib/
python3 setup.py bdist_wheel
# Build the docs
python3 -m sphinx --color -n -W --keep-going -b html docs docs/_build
# Test the doc examples
python3 -m sphinx --color -n -W --keep-going -b doctest docs docs/_build
How-tos
Disassemble (decode and format instructions)
This example uses a Decoder
and one of the Formatter
s to decode and format the code.
The last part shows how to use format specifiers to format instructions.
from iced_x86 import *
# This example produces the following output:
# 00007FFAC46ACDA4 48895C2410 mov [rsp+10h],rbx
# 00007FFAC46ACDA9 4889742418 mov [rsp+18h],rsi
# 00007FFAC46ACDAE 55 push rbp
# 00007FFAC46ACDAF 57 push rdi
# 00007FFAC46ACDB0 4156 push r14
# 00007FFAC46ACDB2 488DAC2400FFFFFF lea rbp,[rsp-100h]
# 00007FFAC46ACDBA 4881EC00020000 sub rsp,200h
# 00007FFAC46ACDC1 488B0518570A00 mov rax,[rel 7FFA`C475`24E0h]
# 00007FFAC46ACDC8 4833C4 xor rax,rsp
# 00007FFAC46ACDCB 488985F0000000 mov [rbp+0F0h],rax
# 00007FFAC46ACDD2 4C8B052F240A00 mov r8,[rel 7FFA`C474`F208h]
# 00007FFAC46ACDD9 488D05787C0400 lea rax,[rel 7FFA`C46F`4A58h]
# 00007FFAC46ACDE0 33FF xor edi,edi
#
# Format specifiers example:
# xchg [rdx+rsi+16h],ah
# xchg %ah,0x16(%rdx,%rsi)
# xchg [rdx+rsi+16h],ah
# xchg ah,[rdx+rsi+16h]
# xchg ah,[rdx+rsi+16h]
# xchgb %ah, %ds:0x16(%rdx,%rsi)
HEXBYTES_COLUMN_BYTE_LENGTH = 10
EXAMPLE_CODE_BITNESS = 64
EXAMPLE_CODE_RIP = 0x0000_7FFA_C46A_CDA4
EXAMPLE_CODE = \
b"\x48\x89\x5C\x24\x10\x48\x89\x74\x24\x18\x55\x57\x41\x56\x48\x8D" \
b"\xAC\x24\x00\xFF\xFF\xFF\x48\x81\xEC\x00\x02\x00\x00\x48\x8B\x05" \
b"\x18\x57\x0A\x00\x48\x33\xC4\x48\x89\x85\xF0\x00\x00\x00\x4C\x8B" \
b"\x05\x2F\x24\x0A\x00\x48\x8D\x05\x78\x7C\x04\x00\x33\xFF"
# Create the decoder and initialize RIP
decoder = Decoder(EXAMPLE_CODE_BITNESS, EXAMPLE_CODE)
decoder.ip = EXAMPLE_CODE_RIP
# Formatters: MASM, NASM, GAS (AT&T) and INTEL (XED).
# There's also `FastFormatter` which is ~1.25x faster. Use it if formatting
# speed is more important than being able to re-assemble formatted
# instructions.
# formatter = FastFormatter()
formatter = Formatter(FormatterSyntax.NASM)
# Change some options, there are many more
formatter.digit_separator = "`"
formatter.first_operand_char_index = 10
# You can also call decoder.can_decode + decoder.decode()/decode_out(instr)
# but the iterator is faster
for instr in decoder:
disasm = formatter.format(instr)
# You can also get only the mnemonic string, or only one or more of the operands:
# mnemonic_str = formatter.format_mnemonic(instr, FormatMnemonicOptions.NO_PREFIXES)
# op0_str = formatter.format_operand(instr, 0)
# operands_str = formatter.format_all_operands(instr)
start_index = instr.ip - EXAMPLE_CODE_RIP
bytes_str = EXAMPLE_CODE[start_index:start_index + instr.len].hex().upper()
# Eg. "00007FFAC46ACDB2 488DAC2400FFFFFF lea rbp,[rsp-100h]"
print(f"{instr.ip:016X} {bytes_str:20} {disasm}")
# Instruction also supports format specifiers, see the table below
decoder = Decoder(64, b"\x86\x64\x32\x16")
decoder.ip = 0x1234_5678
instr = decoder.decode()
print()
print("Format specifiers example:")
print(f"{instr:f}")
print(f"{instr:g}")
print(f"{instr:i}")
print(f"{instr:m}")
print(f"{instr:n}")
print(f"{instr:gG_xSs}")
# ====== =============================================================================
# F-Spec Description
# ====== =============================================================================
# f Fast formatter (masm-like syntax)
# g GNU Assembler formatter
# i Intel (XED) formatter
# m masm formatter
# n nasm formatter
# X Uppercase hex numbers with ``0x`` prefix
# x Lowercase hex numbers with ``0x`` prefix
# H Uppercase hex numbers with ``h`` suffix
# h Lowercase hex numbers with ``h`` suffix
# r RIP-relative memory operands use RIP register instead of abs addr (``[rip+123h]`` vs ``[123456789ABCDEF0h]``)
# U Uppercase everything except numbers and hex prefixes/suffixes (ignored by fast fmt)
# s Add a space after the operand separator
# S Always show the segment register
# B Don't show the branch size (``SHORT`` or ``NEAR PTR``) (ignored by fast fmt)
# G (GNU Assembler): Add mnemonic size suffix (eg. ``movl`` vs ``mov``)
# M Always show the memory size (eg. ``BYTE PTR``) even when not needed
# _ Use digit separators (eg. ``0x12345678`` vs ``0x1234_5678``) (ignored by fast fmt)
# ====== =============================================================================
Create and encode instructions
This example uses a BlockEncoder
to encode created Instruction
s.
from iced_x86 import *
bitness = 64
# All created instructions get an IP of 0. The label id is just an IP.
# The branch instruction's *target* IP should be equal to the IP of the
# target instruction.
label_id: int = 1
def create_label() -> int:
global label_id
idd = label_id
label_id += 1
return idd
def add_label(id: int, instruction: Instruction) -> Instruction:
instruction.ip = id
return instruction
label1 = create_label()
instructions = []
instructions.append(Instruction.create_reg(Code.PUSH_R64, Register.RBP))
instructions.append(Instruction.create_reg(Code.PUSH_R64, Register.RDI))
instructions.append(Instruction.create_reg(Code.PUSH_R64, Register.RSI))
instructions.append(Instruction.create_reg_u32(
Code.SUB_RM64_IMM32, Register.RSP, 0x50))
instructions.append(Instruction.create(Code.VEX_VZEROUPPER))
instructions.append(Instruction.create_reg_mem(
Code.LEA_R64_M, Register.RBP, MemoryOperand(Register.RSP, displ=0x60)))
instructions.append(Instruction.create_reg_reg(
Code.MOV_R64_RM64, Register.RSI, Register.RCX))
instructions.append(Instruction.create_reg_mem(
Code.LEA_R64_M, Register.RDI, MemoryOperand(Register.RBP, displ=-0x38)))
instructions.append(Instruction.create_reg_i32(
Code.MOV_R32_IMM32, Register.ECX, 0x0A))
instructions.append(Instruction.create_reg_reg(
Code.XOR_R32_RM32, Register.EAX, Register.EAX))
instructions.append(Instruction.create_rep_stosd(bitness))
instructions.append(Instruction.create_reg_u64(
Code.CMP_RM64_IMM32, Register.RSI, 0x1234_5678))
# Create a branch instruction that references label1
instructions.append(Instruction.create_branch(Code.JNE_REL32_64, label1))
instructions.append(Instruction.create(Code.NOPD))
# Add the instruction that is the target of the branch
instructions.append(add_label(label1, Instruction.create_reg_reg(
Code.XOR_R32_RM32, Register.R15D, Register.R15D)))
# Create an instruction that accesses some data using an RIP relative memory operand
data1 = create_label()
instructions.append(Instruction.create_reg_mem(
Code.LEA_R64_M, Register.R14, MemoryOperand(Register.RIP, displ=data1)))
instructions.append(Instruction.create(Code.NOPD))
raw_data = b"\x12\x34\x56\x78"
instructions.append(
add_label(data1, Instruction.create_declare_byte(raw_data)))
# Use BlockEncoder to encode a block of instructions. This block can contain any
# number of branches and any number of instructions.
# It uses Encoder to encode all instructions.
# If the target of a branch is too far away, it can fix it to use a longer branch.
# This can be disabled by passing in `False` to the ctor.
target_rip = 0x0000_1248_FC84_0000
encoder = BlockEncoder(bitness)
encoder.add_many(instructions)
encoded_bytes = encoder.encode(target_rip)
# Now disassemble the encoded instructions. Note that the 'jmp near'
# instruction was turned into a 'jmp short' instruction because we
# didn't disable branch optimizations.
bytes_code = encoded_bytes[0:len(encoded_bytes) - len(raw_data)]
bytes_data = encoded_bytes[len(encoded_bytes) - len(raw_data):]
decoder = Decoder(bitness, bytes_code)
decoder.ip = target_rip
formatter = Formatter(FormatterSyntax.GAS)
formatter.first_operand_char_index = 8
for instruction in decoder:
disasm = formatter.format(instruction)
print(f"{instruction.ip:016X} {disasm}")
db = Instruction.create_declare_byte(bytes_data)
print(f"{decoder.ip:016X} {formatter.format(db)}")
# Output:
# 00001248FC840000 push %rbp
# 00001248FC840001 push %rdi
# 00001248FC840002 push %rsi
# 00001248FC840003 sub $0x50,%rsp
# 00001248FC84000A vzeroupper
# 00001248FC84000D lea 0x60(%rsp),%rbp
# 00001248FC840012 mov %rcx,%rsi
# 00001248FC840015 lea -0x38(%rbp),%rdi
# 00001248FC840019 mov $0xA,%ecx
# 00001248FC84001E xor %eax,%eax
# 00001248FC840020 rep stos %eax,(%rdi)
# 00001248FC840022 cmp $0x12345678,%rsi
# 00001248FC840029 jne 0x00001248FC84002C
# 00001248FC84002B nop
# 00001248FC84002C xor %r15d,%r15d
# 00001248FC84002F lea 0x1248FC840037,%r14
# 00001248FC840036 nop
# 00001248FC840037 .byte 0x12,0x34,0x56,0x78
Move code in memory (eg. hook a function)
Uses instruction info API and the encoder to patch a function to jump to the programmer's function.
from iced_x86 import *
# Decodes instructions from some address, then encodes them starting at some
# other address. This can be used to hook a function. You decode enough instructions
# until you have enough bytes to add a JMP instruction that jumps to your code.
# Your code will then conditionally jump to the original code that you re-encoded.
#
# This code uses the BlockEncoder which will help with some things, eg. converting
# short branches to longer branches if the target is too far away.
#
# 64-bit mode also supports RIP relative addressing, but the encoder can't rewrite
# those to use a longer displacement. If any of the moved instructions have RIP
# relative addressing and it tries to access data too far away, the encoder will fail.
# The easiest solution is to use OS alloc functions that allocate memory close to the
# original code (+/-2GB).
# This example produces the following output:
# Original code:
# 00007FFAC46ACDA4 mov [rsp+10h],rbx
# 00007FFAC46ACDA9 mov [rsp+18h],rsi
# 00007FFAC46ACDAE push rbp
# 00007FFAC46ACDAF push rdi
# 00007FFAC46ACDB0 push r14
# 00007FFAC46ACDB2 lea rbp,[rsp-100h]
# 00007FFAC46ACDBA sub rsp,200h
# 00007FFAC46ACDC1 mov rax,[rel 7FFAC47524E0h]
# 00007FFAC46ACDC8 xor rax,rsp
# 00007FFAC46ACDCB mov [rbp+0F0h],rax
# 00007FFAC46ACDD2 mov r8,[rel 7FFAC474F208h]
# 00007FFAC46ACDD9 lea rax,[rel 7FFAC46F4A58h]
# 00007FFAC46ACDE0 xor edi,edi
#
# Original + patched code:
# 00007FFAC46ACDA4 mov rax,123456789ABCDEF0h
# 00007FFAC46ACDAE jmp rax
# 00007FFAC46ACDB0 push r14
# 00007FFAC46ACDB2 lea rbp,[rsp-100h]
# 00007FFAC46ACDBA sub rsp,200h
# 00007FFAC46ACDC1 mov rax,[rel 7FFAC47524E0h]
# 00007FFAC46ACDC8 xor rax,rsp
# 00007FFAC46ACDCB mov [rbp+0F0h],rax
# 00007FFAC46ACDD2 mov r8,[rel 7FFAC474F208h]
# 00007FFAC46ACDD9 lea rax,[rel 7FFAC46F4A58h]
# 00007FFAC46ACDE0 xor edi,edi
#
# Moved code:
# 00007FFAC48ACDA4 mov [rsp+10h],rbx
# 00007FFAC48ACDA9 mov [rsp+18h],rsi
# 00007FFAC48ACDAE push rbp
# 00007FFAC48ACDAF push rdi
# 00007FFAC48ACDB0 jmp 00007FFAC46ACDB0h
def disassemble(data: bytes, ip: int) -> None:
formatter = Formatter(FormatterSyntax.NASM)
decoder = Decoder(EXAMPLE_CODE_BITNESS, data)
decoder.ip = ip
for instruction in decoder:
disasm = formatter.format(instruction)
print(f"{instruction.ip:016X} {disasm}")
print()
def how_to_move_code() -> None:
print("Original code:")
disassemble(EXAMPLE_CODE, EXAMPLE_CODE_RIP)
decoder = Decoder(EXAMPLE_CODE_BITNESS, EXAMPLE_CODE)
decoder.ip = EXAMPLE_CODE_RIP
# In 64-bit mode, we need 12 bytes to jump to any address:
# mov rax,imm64 # 10
# jmp rax # 2
# We overwrite rax because it's probably not used by the called function.
# In 32-bit mode, a normal JMP is just 5 bytes
required_bytes = 10 + 2
total_bytes = 0
orig_instructions = []
for instr in decoder:
orig_instructions.append(instr)
total_bytes += instr.len
if not instr:
raise ValueError("Found garbage")
if total_bytes >= required_bytes:
break
cflow = instr.flow_control
if cflow == FlowControl.NEXT:
pass # nothing
elif cflow == FlowControl.UNCONDITIONAL_BRANCH:
if instr.op0_kind == OpKind.NEAR_BRANCH64:
_target = instr.near_branch_target
# You could check if it's just jumping forward a few bytes and follow it
# but this is a simple example so we'll fail.
raise ValueError("Not supported by this simple example")
else:
raise ValueError("Not supported by this simple example")
if total_bytes < required_bytes:
raise ValueError("Not enough bytes!")
if len(orig_instructions) == 0:
raise ValueError("Should not be empty here")
# Create a JMP instruction that branches to the original code, except those instructions
# that we'll re-encode. We don't need to do it if it already ends in 'ret'
last_instr = orig_instructions[-1]
if last_instr.flow_control != FlowControl.RETURN:
orig_instructions.append(Instruction.create_branch(Code.JMP_REL32_64, last_instr.next_ip))
# Relocate the code to some new location. It can fix short/near branches and
# convert them to short/near/long forms if needed. This also works even if it's a
# jrcxz/loop/loopcc instruction which only have short forms.
#
# It can currently only fix RIP relative operands if the new location is within 2GB
# of the target data location.
relocated_base_address = EXAMPLE_CODE_RIP + 0x20_0000
encoder = BlockEncoder(decoder.bitness)
encoder.add_many(orig_instructions)
new_code = encoder.encode(relocated_base_address)
# Patch the original code. Pretend that we use some OS API to write to memory...
# We could use the BlockEncoder/Encoder for this but it's easy to do yourself too.
# This is 'mov rax,imm64; jmp rax'
YOUR_FUNC: int = 0x1234_5678_9ABC_DEF0 # Address of your code
example_code = bytearray(EXAMPLE_CODE)
example_code[0] = 0x48 # \ 'MOV RAX,imm64'
example_code[1] = 0xB8 # /
v = YOUR_FUNC
for i in range(2, 10):
example_code[i] = v & 0xFF
v >>= 8
example_code[10] = 0xFF # \ JMP RAX
example_code[11] = 0xE0 # /
# Disassemble it
print("Original + patched code:")
disassemble(example_code, EXAMPLE_CODE_RIP)
# Disassemble the moved code
print("Moved code:")
disassemble(new_code, relocated_base_address)
EXAMPLE_CODE_BITNESS: int = 64
EXAMPLE_CODE_RIP: int = 0x0000_7FFA_C46A_CDA4
EXAMPLE_CODE: bytes = \
b"\x48\x89\x5C\x24\x10\x48\x89\x74\x24\x18\x55\x57\x41\x56\x48\x8D" \
b"\xAC\x24\x00\xFF\xFF\xFF\x48\x81\xEC\x00\x02\x00\x00\x48\x8B\x05" \
b"\x18\x57\x0A\x00\x48\x33\xC4\x48\x89\x85\xF0\x00\x00\x00\x4C\x8B" \
b"\x05\x2F\x24\x0A\x00\x48\x8D\x05\x78\x7C\x04\x00\x33\xFF"
how_to_move_code()
Get instruction info, eg. read/written regs/mem, control flow info, etc
Shows how to get used registers/memory and other info. It uses Instruction
methods
and an InstructionInfoFactory
to get this info.
from iced_x86 import *
from typing import Dict, Sequence
from types import ModuleType
# This code produces the following output:
# 00007FFAC46ACDA4 mov [rsp+10h],rbx
# OpCode: o64 89 /r
# Instruction: MOV r/m64, r64
# Encoding: LEGACY
# Mnemonic: MOV
# Code: MOV_RM64_R64
# CpuidFeature: X64
# FlowControl: NEXT
# Displacement offset = 4, size = 1
# Memory size: 8
# Op0Access: WRITE
# Op1Access: READ
# Op0: R64_OR_MEM
# Op1: R64_REG
# Used reg: RSP:READ
# Used reg: RBX:READ
# Used mem: [SS:RSP+0x10;UINT64;WRITE]
# 00007FFAC46ACDA9 mov [rsp+18h],rsi
# OpCode: o64 89 /r
# Instruction: MOV r/m64, r64
# Encoding: LEGACY
# Mnemonic: MOV
# Code: MOV_RM64_R64
# CpuidFeature: X64
# FlowControl: NEXT
# Displacement offset = 4, size = 1
# Memory size: 8
# Op0Access: WRITE
# Op1Access: READ
# Op0: R64_OR_MEM
# Op1: R64_REG
# Used reg: RSP:READ
# Used reg: RSI:READ
# Used mem: [SS:RSP+0x18;UINT64;WRITE]
# 00007FFAC46ACDAE push rbp
# OpCode: o64 50+ro
# Instruction: PUSH r64
# Encoding: LEGACY
# Mnemonic: PUSH
# Code: PUSH_R64
# CpuidFeature: X64
# FlowControl: NEXT
# SP Increment: -8
# Op0Access: READ
# Op0: R64_OPCODE
# Used reg: RBP:READ
# Used reg: RSP:READ_WRITE
# Used mem: [SS:RSP+0xFFFFFFFFFFFFFFF8;UINT64;WRITE]
# 00007FFAC46ACDAF push rdi
# OpCode: o64 50+ro
# Instruction: PUSH r64
# Encoding: LEGACY
# Mnemonic: PUSH
# Code: PUSH_R64
# CpuidFeature: X64
# FlowControl: NEXT
# SP Increment: -8
# Op0Access: READ
# Op0: R64_OPCODE
# Used reg: RDI:READ
# Used reg: RSP:READ_WRITE
# Used mem: [SS:RSP+0xFFFFFFFFFFFFFFF8;UINT64;WRITE]
# 00007FFAC46ACDB0 push r14
# OpCode: o64 50+ro
# Instruction: PUSH r64
# Encoding: LEGACY
# Mnemonic: PUSH
# Code: PUSH_R64
# CpuidFeature: X64
# FlowControl: NEXT
# SP Increment: -8
# Op0Access: READ
# Op0: R64_OPCODE
# Used reg: R14:READ
# Used reg: RSP:READ_WRITE
# Used mem: [SS:RSP+0xFFFFFFFFFFFFFFF8;UINT64;WRITE]
# 00007FFAC46ACDB2 lea rbp,[rsp-100h]
# OpCode: o64 8D /r
# Instruction: LEA r64, m
# Encoding: LEGACY
# Mnemonic: LEA
# Code: LEA_R64_M
# CpuidFeature: X64
# FlowControl: NEXT
# Displacement offset = 4, size = 4
# Op0Access: WRITE
# Op1Access: NO_MEM_ACCESS
# Op0: R64_REG
# Op1: MEM
# Used reg: RBP:WRITE
# Used reg: RSP:READ
# 00007FFAC46ACDBA sub rsp,200h
# OpCode: o64 81 /5 id
# Instruction: SUB r/m64, imm32
# Encoding: LEGACY
# Mnemonic: SUB
# Code: SUB_RM64_IMM32
# CpuidFeature: X64
# FlowControl: NEXT
# Immediate offset = 3, size = 4
# RFLAGS Written: OF, SF, ZF, AF, CF, PF
# RFLAGS Modified: OF, SF, ZF, AF, CF, PF
# Op0Access: READ_WRITE
# Op1Access: READ
# Op0: R64_OR_MEM
# Op1: IMM32SEX64
# Used reg: RSP:READ_WRITE
# 00007FFAC46ACDC1 mov rax,[7FFAC47524E0h]
# OpCode: o64 8B /r
# Instruction: MOV r64, r/m64
# Encoding: LEGACY
# Mnemonic: MOV
# Code: MOV_R64_RM64
# CpuidFeature: X64
# FlowControl: NEXT
# Displacement offset = 3, size = 4
# Memory size: 8
# Op0Access: WRITE
# Op1Access: READ
# Op0: R64_REG
# Op1: R64_OR_MEM
# Used reg: RAX:WRITE
# Used mem: [DS:0x7FFAC47524E0;UINT64;READ]
# 00007FFAC46ACDC8 xor rax,rsp
# OpCode: o64 33 /r
# Instruction: XOR r64, r/m64
# Encoding: LEGACY
# Mnemonic: XOR
# Code: XOR_R64_RM64
# CpuidFeature: X64
# FlowControl: NEXT
# RFLAGS Written: SF, ZF, PF
# RFLAGS Cleared: OF, CF
# RFLAGS Undefined: AF
# RFLAGS Modified: OF, SF, ZF, AF, CF, PF
# Op0Access: READ_WRITE
# Op1Access: READ
# Op0: R64_REG
# Op1: R64_OR_MEM
# Used reg: RAX:READ_WRITE
# Used reg: RSP:READ
# 00007FFAC46ACDCB mov [rbp+0F0h],rax
# OpCode: o64 89 /r
# Instruction: MOV r/m64, r64
# Encoding: LEGACY
# Mnemonic: MOV
# Code: MOV_RM64_R64
# CpuidFeature: X64
# FlowControl: NEXT
# Displacement offset = 3, size = 4
# Memory size: 8
# Op0Access: WRITE
# Op1Access: READ
# Op0: R64_OR_MEM
# Op1: R64_REG
# Used reg: RBP:READ
# Used reg: RAX:READ
# Used mem: [SS:RBP+0xF0;UINT64;WRITE]
# 00007FFAC46ACDD2 mov r8,[7FFAC474F208h]
# OpCode: o64 8B /r
# Instruction: MOV r64, r/m64
# Encoding: LEGACY
# Mnemonic: MOV
# Code: MOV_R64_RM64
# CpuidFeature: X64
# FlowControl: NEXT
# Displacement offset = 3, size = 4
# Memory size: 8
# Op0Access: WRITE
# Op1Access: READ
# Op0: R64_REG
# Op1: R64_OR_MEM
# Used reg: R8:WRITE
# Used mem: [DS:0x7FFAC474F208;UINT64;READ]
# 00007FFAC46ACDD9 lea rax,[7FFAC46F4A58h]
# OpCode: o64 8D /r
# Instruction: LEA r64, m
# Encoding: LEGACY
# Mnemonic: LEA
# Code: LEA_R64_M
# CpuidFeature: X64
# FlowControl: NEXT
# Displacement offset = 3, size = 4
# Op0Access: WRITE
# Op1Access: NO_MEM_ACCESS
# Op0: R64_REG
# Op1: MEM
# Used reg: RAX:WRITE
# 00007FFAC46ACDE0 xor edi,edi
# OpCode: o32 33 /r
# Instruction: XOR r32, r/m32
# Encoding: LEGACY
# Mnemonic: XOR
# Code: XOR_R32_RM32
# CpuidFeature: INTEL386
# FlowControl: NEXT
# RFLAGS Cleared: OF, SF, CF
# RFLAGS Set: ZF, PF
# RFLAGS Undefined: AF
# RFLAGS Modified: OF, SF, ZF, AF, CF, PF
# Op0Access: WRITE
# Op1Access: NONE
# Op0: R32_REG
# Op1: R32_OR_MEM
# Used reg: RDI:WRITE
def how_to_get_instruction_info() -> None:
decoder = Decoder(EXAMPLE_CODE_BITNESS, EXAMPLE_CODE)
decoder.ip = EXAMPLE_CODE_RIP
# Use a factory to create the instruction info if you need register and
# memory usage. If it's something else, eg. encoding, flags, etc, there
# are Instruction methods that can be used instead.
info_factory = InstructionInfoFactory()
for instr in decoder:
# Gets offsets in the instruction of the displacement and immediates and their sizes.
# This can be useful if there are relocations in the binary. The encoder has a similar
# method. This method must be called after decode() and you must pass in the last
# instruction decode() returned.
offsets = decoder.get_constant_offsets(instr)
print(f"{instr.ip:016X} {instr}")
op_code = instr.op_code()
info = info_factory.info(instr)
fpu_info = instr.fpu_stack_increment_info()
print(f" OpCode: {op_code.op_code_string}")
print(f" Instruction: {op_code.instruction_string}")
print(f" Encoding: {encoding_kind_to_string(instr.encoding)}")
print(f" Mnemonic: {mnemonic_to_string(instr.mnemonic)}")
print(f" Code: {code_to_string(instr.code)}")
print(f" CpuidFeature: {cpuid_features_to_string(instr.cpuid_features())}")
print(f" FlowControl: {flow_control_to_string(instr.flow_control)}")
if offsets.has_displacement:
print(f" Displacement offset = {offsets.displacement_offset}, size = {offsets.displacement_size}")
if fpu_info.writes_top:
if fpu_info.increment == 0:
print(f" FPU TOP: the instruction overwrites TOP")
else:
print(f" FPU TOP inc: {fpu_info.increment}")
cond_write = "true" if fpu_info.conditional else "false"
print(f" FPU TOP cond write: {cond_write}")
if offsets.has_immediate:
print(f" Immediate offset = {offsets.immediate_offset}, size = {offsets.immediate_size}")
if offsets.has_immediate2:
print(f" Immediate #2 offset = {offsets.immediate_offset2}, size = {offsets.immediate_size2}")
if instr.is_stack_instruction:
print(f" SP Increment: {instr.stack_pointer_increment}")
if instr.condition_code != ConditionCode.NONE:
print(f" Condition code: {instr.condition_code}")
if instr.rflags_read != RflagsBits.NONE:
print(f" RFLAGS Read: {rflags_bits_to_string(instr.rflags_read)}")
if instr.rflags_written != RflagsBits.NONE:
print(f" RFLAGS Written: {rflags_bits_to_string(instr.rflags_written)}")
if instr.rflags_cleared != RflagsBits.NONE:
print(f" RFLAGS Cleared: {rflags_bits_to_string(instr.rflags_cleared)}")
if instr.rflags_set != RflagsBits.NONE:
print(f" RFLAGS Set: {rflags_bits_to_string(instr.rflags_set)}")
if instr.rflags_undefined != RflagsBits.NONE:
print(f" RFLAGS Undefined: {rflags_bits_to_string(instr.rflags_undefined)}")
if instr.rflags_modified != RflagsBits.NONE:
print(f" RFLAGS Modified: {rflags_bits_to_string(instr.rflags_modified)}")
for i in range(instr.op_count):
op_kind = instr.op_kind(i)
if op_kind == OpKind.MEMORY or op_kind == OpKind.MEMORY64:
size = MemorySizeExt.size(instr.memory_size)
if size != 0:
print(f" Memory size: {size}")
break
for i in range(instr.op_count):
print(f" Op{i}Access: {op_access_to_string(info.op_access(i))}")
for i in range(op_code.op_count):
print(f" Op{i}: {op_code_operand_kind_to_string(op_code.op_kind(i))}")
for reg_info in info.used_registers():
print(f" Used reg: {used_reg_to_string(reg_info)}")
for mem_info in info.used_memory():
print(f" Used mem: {used_mem_to_string(mem_info)}")
def rflags_bits_to_string(rf: int) -> str:
def append(sb: str, s: str) -> str:
if len(sb) != 0:
sb += ", "
return sb + s
sb = ""
if (rf & RflagsBits.OF) != 0:
sb = append(sb, "OF")
if (rf & RflagsBits.SF) != 0:
sb = append(sb, "SF")
if (rf & RflagsBits.ZF) != 0:
sb = append(sb, "ZF")
if (rf & RflagsBits.AF) != 0:
sb = append(sb, "AF")
if (rf & RflagsBits.CF) != 0:
sb = append(sb, "CF")
if (rf & RflagsBits.PF) != 0:
sb = append(sb, "PF")
if (rf & RflagsBits.DF) != 0:
sb = append(sb, "DF")
if (rf & RflagsBits.IF) != 0:
sb = append(sb, "IF")
if (rf & RflagsBits.AC) != 0:
sb = append(sb, "AC")
if (rf & RflagsBits.UIF) != 0:
sb = append(sb, "UIF")
if len(sb) == 0:
return "<empty>"
return sb
EXAMPLE_CODE_BITNESS: int = 64
EXAMPLE_CODE_RIP: int = 0x0000_7FFA_C46A_CDA4
EXAMPLE_CODE: bytes = \
b"\x48\x89\x5C\x24\x10\x48\x89\x74\x24\x18\x55\x57\x41\x56\x48\x8D" \
b"\xAC\x24\x00\xFF\xFF\xFF\x48\x81\xEC\x00\x02\x00\x00\x48\x8B\x05" \
b"\x18\x57\x0A\x00\x48\x33\xC4\x48\x89\x85\xF0\x00\x00\x00\x4C\x8B" \
b"\x05\x2F\x24\x0A\x00\x48\x8D\x05\x78\x7C\x04\x00\x33\xFF"
def create_enum_dict(module: ModuleType) -> Dict[int, str]:
return {module.__dict__[key]:key for key in module.__dict__ if isinstance(module.__dict__[key], int)}
REGISTER_TO_STRING: Dict[int, str] = create_enum_dict(Register)
def register_to_string(value: int) -> str:
s = REGISTER_TO_STRING.get(value)
if s is None:
return str(value) + " /*Register enum*/"
return s
OP_ACCESS_TO_STRING: Dict[int, str] = create_enum_dict(OpAccess)
def op_access_to_string(value: int) -> str:
s = OP_ACCESS_TO_STRING.get(value)
if s is None:
return str(value) + " /*OpAccess enum*/"
return s
ENCODING_KIND_TO_STRING: Dict[int, str] = create_enum_dict(EncodingKind)
def encoding_kind_to_string(value: int) -> str:
s = ENCODING_KIND_TO_STRING.get(value)
if s is None:
return str(value) + " /*EncodingKind enum*/"
return s
MNEMONIC_TO_STRING: Dict[int, str] = create_enum_dict(Mnemonic)
def mnemonic_to_string(value: int) -> str:
s = MNEMONIC_TO_STRING.get(value)
if s is None:
return str(value) + " /*Mnemonic enum*/"
return s
CODE_TO_STRING: Dict[int, str] = create_enum_dict(Code)
def code_to_string(value: int) -> str:
s = CODE_TO_STRING.get(value)
if s is None:
return str(value) + " /*Code enum*/"
return s
FLOW_CONTROL_TO_STRING: Dict[int, str] = create_enum_dict(FlowControl)
def flow_control_to_string(value: int) -> str:
s = FLOW_CONTROL_TO_STRING.get(value)
if s is None:
return str(value) + " /*FlowControl enum*/"
return s
OP_CODE_OPERAND_KIND_TO_STRING: Dict[int, str] = create_enum_dict(OpCodeOperandKind)
def op_code_operand_kind_to_string(value: int) -> str:
s = OP_CODE_OPERAND_KIND_TO_STRING.get(value)
if s is None:
return str(value) + " /*OpCodeOperandKind enum*/"
return s
CPUID_FEATURE_TO_STRING: Dict[int, str] = create_enum_dict(CpuidFeature)
def cpuid_feature_to_string(value: int) -> str:
s = CPUID_FEATURE_TO_STRING.get(value)
if s is None:
return str(value) + " /*CpuidFeature enum*/"
return s
def cpuid_features_to_string(cpuid_features: Sequence[int]) -> str:
return " and ".join([cpuid_feature_to_string(f) for f in cpuid_features])
MEMORY_SIZE_TO_STRING: Dict[int, str] = create_enum_dict(MemorySize)
def memory_size_to_string(value: int) -> str:
s = MEMORY_SIZE_TO_STRING.get(value)
if s is None:
return str(value) + " /*MemorySize enum*/"
return s
def used_reg_to_string(reg_info: UsedRegister) -> str:
return register_to_string(reg_info.register) + ":" + op_access_to_string(reg_info.access)
def used_mem_to_string(mem_info: UsedMemory) -> str:
sb = "[" + register_to_string(mem_info.segment) + ":"
need_plus = mem_info.base != Register.NONE
if need_plus:
sb += register_to_string(mem_info.base)
if mem_info.index != Register.NONE:
if need_plus:
sb += "+"
need_plus = True
sb += register_to_string(mem_info.index)
if mem_info.scale != 1:
sb += "*" + str(mem_info.scale)
if mem_info.displacement != 0 or not need_plus:
if need_plus:
sb += "+"
sb += f"0x{mem_info.displacement:X}"
sb += ";" + memory_size_to_string(mem_info.memory_size) + ";" + op_access_to_string(mem_info.access) + "]"
return sb
how_to_get_instruction_info()
Disassemble old/deprecated CPU instructions
from iced_x86 import *
# This example produces the following output:
# 731E0A03 bndmov bnd1, [eax]
# 731E0A07 mov tr3, esi
# 731E0A0A rdshr [eax]
# 731E0A0D dmint
# 731E0A0F svdc [eax], cs
# 731E0A12 cpu_read
# 731E0A14 pmvzb mm1, [eax]
# 731E0A17 frinear
# 731E0A19 altinst
TEST_CODE = \
b"\x66\x0F\x1A\x08" \
b"\x0F\x26\xDE" \
b"\x0F\x36\x00" \
b"\x0F\x39" \
b"\x0F\x78\x08" \
b"\x0F\x3D" \
b"\x0F\x58\x08" \
b"\xDF\xFC" \
b"\x0F\x3F"
# Enable decoding of Cyrix/Geode instructions, Centaur ALTINST,
# MOV to/from TR and MPX instructions.
# There are other options to enable other instructions such as UMOV, etc.
# These are deprecated instructions or only used by old CPUs so they're not
# enabled by default. Some newer instructions also use the same opcodes as
# some of these old instructions.
DECODER_OPTIONS = DecoderOptions.MPX | \
DecoderOptions.MOV_TR | \
DecoderOptions.CYRIX | \
DecoderOptions.CYRIX_DMI | \
DecoderOptions.ALTINST
decoder = Decoder(32, TEST_CODE, DECODER_OPTIONS)
decoder.ip = 0x731E_0A03
for instr in decoder:
# 'n' format specifier means NASM formatter, see the disassemble
# example for all possible format specifiers
print(f"{instr.ip:08X} {instr:ns}")