Advanced syntax highlighting for GNU As
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This vim bundle adds advanced syntax highlighting for GNU as (AT&T).

This file defines a (almost) complete syntax for GNU as assembler.

My motivation in writing this was the lack of a complete, working syntax for this common assembler.

For now the basic as directives as well as the Intel / AMD, ARM (thumb) and AVR instruction sets are included.
Opcodes supporting a size suffix are recognized plain as well as suffixed with b/w/l/q.

What does it look like?

screenshot here..

Supported instructions a per version 0.13:

  • X86 common instruction set (8086 - 686)
  • Katmai Streaming SIMD instructions (SSE -- a.k.a. KNI, XMM, MMX2)
  • Introduced in Deschutes but necessary for SSE support
  • XSAVE group (AVX and extended state)
  • Generic memory operations
  • New MMX instructions introduced in Katmai
  • AMD Enhanced 3DNow! (Athlon) instructions
  • Willamette SSE2 Cacheability Instructions
  • Willamette MMX instructions (SSE2 SIMD Integer Instructions)
  • Willamette Streaming SIMD instructions (SSE2)
  • Prescott New Instructions (SSE3)
  • VMX Instructions
  • Extended Page Tables VMX instructions
  • Tejas New Instructions (SSSE3)
  • New instructions in Barcelona
  • Penryn New Instructions (SSE4.1)
  • Nehalem New Instructions (SSE4.2)
  • AMD SSE5 instructions
  • Intel SMX
  • Geode (Cyrix) 3DNow! additions
  • Intel AES instructions
  • Intel AVX AES instructions
  • Intel AVX instructions
  • Intel Carry-Less Multiplication instructions (CLMUL)
  • Intel AVX Carry-Less Multiplication instructions (CLMUL)
  • Intel Fused Multiply-Add instructions (FMA)
  • VIA (Centaur) security instructions
  • AMD XOP, FMA4 and CVT16 instructions (SSE5)
  • Systematic names for the hinting nop instructions
  • ARM (Thumb)
  • AVR

You can set different highlighting for each set listed above by adding a line like this to you .vimrc:

  hi def link gasOpcodeX86_PENT_SSE  <some_highlighting> 

per-file opcode enable / disable

Since version 0.6 it is possible to disable sets of opcodes by either CPU they where introduced in or by their extension name. This is done by setting a special variable recognized by gas.vim to the list of disabled opcodes.


" globally disable all x86_64 opcodes 
:let g:gasDisableOpcodes='x86_64' 

" disable SSE and SSE2 for this buffer 
let b:gasDisableOpcodes='sse sse2' 

Disabled opcodes will be highlighted as errors.

recognized CPU groups:

       186, 286, 386, 3862, 486, 8086, amd, future, ia64, katmai, nehalem, 
        p6, pentium_m, pentium, prescott, sandybridge, x64, x642, x86_64 

recognized extension groups:

       base, 3dnow, mmx, mmx2, sse, sse2, sse3, ssse3, sse4.1, sse4.2, sse4a, 
       sse5, avx, fma, vmx 

I hope this syntax file will be useful to other people - but don't blame me if it doesn't suit your needs.

CPP preprocessor macros

GAS allows code to be processed by the same preprocessor used for C/C++ code. So directives like #include, #define etc. will be highlighted using the C syntax highlighter if available.

This behavior can be turned off by setting the gasDisablePreproc option either globally in your .vimrc or on a per-buffer basis:

" globally disable preprocessor macro detection
:let g:gasDisablePreproc=1 

" disable only for this buffer 
let gasDisablePreproc=1 


This syntax file can either be installed manually, by using pathogen or vundle.

Manual Installation

Download gas.vim and copy the file to .vim/syntax/ in your home folder. Add this line to the end of your file:

/* vim: ft=gas : 

Installation with Git & Pathogen

  • Install pathogen into ~/.vim/autoload/ and add the following line to your ~/.vimrc:

      call pathogen#infect()
  • Make a clone of the vim-gas repository:

      $ mkdir -p ~/.vim/bundle
      $ cd ~/.vim/bundle
      $ git clone
  • OR use git submodules:

      $ git submodule add bundle/vim-gas
      $ git submodule init

Installation with Vundle

  • Install and setup vundle then add this to your ~/.vimrc inside the vundle#begin() / vundle#end() block:

      Plugin shirk/vim-gas
  • Restart your vim and call VundleInstall


BSD (3 clause) - see LICENSE for details