Zydis  v2.0.0-alpha2
Zyan Disassembler Engine (Zydis)

License: MIT Gitter

Fast and lightweight x86/x86-64 disassembler library.


  • Supports all x86 and x86-64 (AMD64) instructions.
  • Supports pretty much all ISA extensions (list incomplete):
    • FPU (x87), MMX
    • SSE, SSE2, SSE3, SSSE3, SSE4.1, SSE4.2, SSE4A, AESNI
    • AVX, AVX2, AVX512BW, AVX512CD, AVX512DQ, AVX512ER, AVX512F, AVX512PF, AVX512VL
    • ADX, BMI1, BMI2, FMA, FMA4
  • Optimized for high performance
  • No dynamic memory allocation ("malloc")
  • Very small file-size overhead compared to other common disassembler libraries
  • Complete doxygen documentation
  • No dependencies on platform specific APIs
    • Should compile on any platform with a complete libc and CMake
    • Tested on Windows, macOS and Linux


  • Language bindings [v2.0 final]
  • Tests [v2.0 final]
  • Graphical editor for the instruction-database [v2.0 final]
  • Implement CMake feature gates. Currently, everything is always included. [v2.0 final]
  • Encoding support [v2.1]

Quick Example

The following example program uses Zydis to disassemble a given memory buffer and prints the output to the console.

#include <stdio.h>
#include <Zydis/Zydis.h>
int main()
uint8_t data[] =
0x51, 0x8D, 0x45, 0xFF, 0x50, 0xFF, 0x75, 0x0C, 0xFF, 0x75,
0x08, 0xFF, 0x15, 0xA0, 0xA5, 0x48, 0x76, 0x85, 0xC0, 0x0F,
0x88, 0xFC, 0xDA, 0x02, 0x00
// Initialize decoder context.
ZydisDecoder decoder;
// Initialize formatter. Only required when you actually plan to
// do instruction formatting ("disassembling"), like we do here.
ZydisFormatter formatter;
// Loop over the instructions in our buffer.
uint64_t instructionPointer = 0x007FFFFFFF400000;
uint8_t* readPointer = data;
size_t length = sizeof(data);
&decoder, readPointer, length, instructionPointer, &instruction)))
// Print current instruction pointer.
printf("%016" PRIX64 " ", instructionPointer);
// Format & print the binary instruction
// structure to human readable format.
char buffer[256];
&formatter, &instruction, buffer, sizeof(buffer));
readPointer += instruction.length;
length -= instruction.length;
instructionPointer += instruction.length;
ZYDIS_EXPORT ZydisStatus ZydisDecoderDecodeBuffer(const ZydisDecoder *decoder, const void *buffer, size_t bufferLen, uint64_t instructionPointer, ZydisDecodedInstruction *instruction)
Decodes the instruction in the given input buffer.
ZYDIS_EXPORT ZydisStatus ZydisDecoderInit(ZydisDecoder *decoder, ZydisMachineMode machineMode, ZydisAddressWidth addressWidth)
Initializes the given ZydisDecoder instance.
ZYDIS_EXPORT ZydisStatus ZydisFormatterInit(ZydisFormatter *formatter, ZydisFormatterStyle style)
Initializes the given ZydisFormatter instance.
Generates intel-style disassembly.
Definition: Formatter.h:60
ZYDIS_EXPORT ZydisStatus ZydisFormatterFormatInstruction(const ZydisFormatter *formatter, ZydisDecodedInstruction *instruction, char *buffer, size_t bufferLen)
Formats the given instruction and writes it into the output buffer.
Definition: SharedTypes.h:120
64 bit mode.
Definition: SharedTypes.h:76
#define ZYDIS_SUCCESS(status)
Checks if a zydis operation was successfull.
Definition: Status.h:157
Master include file, including everything else.
Defines the ZydisDecodedInstruction struct.
Definition: DecoderTypes.h:740
uint8_t length
The length of the decoded instruction.
Definition: DecoderTypes.h:752
Defines the ZydisDecoder struct.
Definition: Decoder.h:87
Defines the ZydisFormatter struct.
Definition: Formatter.h:459

Sample Output

The above example program generates the following output:

007FFFFFFF400000 push rcx
007FFFFFFF400001 lea eax, [rbp-0x01]
007FFFFFFF400004 push rax
007FFFFFFF400005 push qword ptr [rbp+0x0C]
007FFFFFFF400008 push qword ptr [rbp+0x08]
007FFFFFFF40000B call [0x008000007588A5B1]
007FFFFFFF400011 test eax, eax
007FFFFFFF400013 js 0x007FFFFFFF42DB15


Zydis builds cleanly on most platforms without any external dependencies. You can use CMake to generate project files for your favorite C99 compiler.

# Linux and OS X
git clone 'https://github.com/zyantific/zydis.git'
cd zydis
mkdir build && cd build
cmake ..

ZydisInfo tool



  • Intel (for open-sourcing XED, allowing for automatic comparision of our tables against theirs, improving both)
  • LLVM (for providing pretty solid instruction data as well)
  • Christian Ludloff (http://sandpile.org, insanely helpful)
  • Our contributors on GitHub


Zydis is licensed under the MIT license.