Assembler toolkit based on AsmJit
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Assembler toolkit based on AsmJit.


AsmTK is a sister project of AsmJit library, which provides concepts that are useful mostly in AOT code-generation.


  • Both X86 and X64 modes are supported and can be selected at runtime (i.e. they not depend on how your application is compiled).
  • Asm parser can parse everything that AsmJit provides (i.e. supports all instruction sets, named labels, etc...).
  • Asm parser can also parse instruction aliases defined by AsmTK (like movsb, cmpsb, sal, ...). AsmJit provides just generic movs, cmps, etc... so these are extras that are handled and recognized by AsmTK.
  • Assembles to any CodeEmitter, which means that you can choose between Assembler and CodeBuilder at runtime, and that the result can be post-processed as well
  • More to be added...


  • More aliases to some SIMD instructions (to be added).
  • Implement asmtk::Linker that will add the possibility to write shared libraries and executables.

AsmParser Usage Guide

Assembler parsing is provided by AsmParser class, which emits to CodeEmitter:

#include <asmtk/asmtk.h>

using namespace asmjit;
using namespace asmtk;

// Used to print binary code as hex.
static void dumpCode(const uint8_t* buf, size_t len) {
  enum { kCharsPerLine = 39 };
  char hex[kCharsPerLine * 2 + 1];

  size_t i = 0;
  while (i < len) {
    size_t j = 0;
    size_t end = len - i < kCharsPerLine ? len - i : size_t(kCharsPerLine);

    end += i;
    while (i < end) {
      uint8_t b0 = buf[i] >> 4;
      uint8_t b1 = buf[i] & 15;

      hex[j++] = b0 < 10 ? '0' + b0 : 'A' + b0 - 10;
      hex[j++] = b1 < 10 ? '0' + b1 : 'A' + b1 - 10;

    hex[j] = '\0';

int main(int argc, char* argv[]) {
  // Setup CodeHolder for X64.
  CodeInfo ci(ArchInfo::kTypeX64);
  CodeHolder code;

  // Attach X86Assembler `code`.
  X86Assembler a(&code);

  // Create AsmParser that will emit to X86Assembler.
  AsmParser p(&a);

  // Parse some assembly.
  Error err = p.parse(
    "mov rax, rbx\n"
    "vaddpd zmm0, zmm1, [rax + 128]\n");

  // Error handling (use asmjit::ErrorHandler for more robust error handling).
  if (err) {
    printf("ERROR: %08x (%s)\n", err, DebugUtils::errorAsString(err));
    return 1;

  // If we are done, you must detach the Assembler from CodeHolder or sync
  // it, so its internal state and position is synced with CodeHolder.

  // Now you can print the code, which is stored in the first section (.text).
  CodeBuffer& buffer = code.getSectionEntry(0)->getBuffer();
  dumpCode(buffer.getData(), buffer.getLength());

  return 0;

You should check out the test directory to see how AsmTK integrates with AsmJit.


Please consider a donation if you use the project and would like to keep it active in the future.

Authors & Maintainers