length-disassembler

A length disassembler for x86-32 and x86-64 written in C.

Known "issues"

• Some invalid opcodes may not get parsed correctly.
• There is no support for AVX and processor-specific instructions.

Interface

// address: a pointer to a buffer containing instructions.
// x86_64_mode: If true, disassembles x86-64 instructions, otherwise disasassembles x86-32 instructions.
size_t ldisasm(const void* const address, const bool x86_64_mode)

Usage

#include "ldisasm.h"

int main()
{
  char buffer[] = { 0x55, 0x8B, 0xEC, 0x53, 0x8B, 0xD9, 0x56, 0x57 };
  size_t instructionLength = ldisasm(buffer, false);
}

References

• Intel® 64 and IA-32 Architectures Software Developer’s Manual Volume 2 (2A, 2B, 2C & 2D): Instruction Set Reference, A-Z
  • Section 2.1
  • Section 2.2.1
  • Appendix A