NASM - The Netwide Assembler

NASM is an awesome 80x86 assembler that’s all about being portable and modular. It supports a bunch of object file formats like Linux a.out, ELF, COFF, Microsoft 16-bit OBJ, and Win32. Plus, it can even output plain binary files!

Simple and Easy Syntax

The syntax for NASM is designed to be straightforward and easy to understand. It's similar to Intel's but way less complicated. It supports various opcodes like Pentium, P6, MMX, 3DNow!, and SSE. And guess what? It even comes with macro capabilities! Oh, and there’s a disassembler included too!

A Little History

So how did NASM come about? Well, it was born from a chat on comp.lang.asm.x86 (or maybe alt.lang.asm – can’t remember!). The idea was pretty simple: there wasn’t a good free x86-series assembler out there. So someone thought it might be cool to create one.

Why Choose NASM?

• a86: Good but not free; you need to pay for 32-bit capability.


• gas: Free but not very user-friendly; it's made to work with gcc.


• as86: More focused on Minix and Linux; lacks documentation.


• MASM: Expensive and only runs under DOS.


• TASM: Better but still pricey with lots of rules that can confuse you.

This is where NASM steps in! Sure, it's still in prototype stage right now, so we can't promise it'll outshine the others just yet. But we’d love your feedback! Send us bug reports or any helpful tips you have – thanks to everyone who has already pitched in!

Getting Started with NASM

If you’re ready to roll with NASM, start by downloading the Unix source archive named nasm-X.XX.tar.gz (where X.XX is the version number). Unpack it into a directory like /usr/local/src. Once unpacked, you’ll find its own subdirectory called nasm-X.XX.

Auto-Configuring Made Easy

NASM is super easy to set up! After unpacking it, just go into that directory and type ./configure. This script will sniff out the best C compiler for building NASM and set up everything for you!

Binaries Installation

Once configured successfully, just type make, which builds the nasm and ndisasm binaries. Then run make install. This installs them in /usr/local/bin along with the man pages nasm.1 and ndisasm.1 in /usr/local/man/man1.

If you want some extra tools for handling custom object-file formats (RDOFF), they’re in the rdoff subdirectory of the NASM archive! Use make rdf, then follow it up with make rdf_install.

Troubleshooting Compilation Issues

If auto-configuration doesn't work out smoothly for you, no worries! You can use the fallback Unix makefile named Makefile.unx instead. Just rename