flat assembler
Open source assembly language compiler.

The flat assembler (abbreviated to fasm) is a fast self-assembling assembler for DOS, Windows and Linux operating systems. It was designed primarily for the assembly of x86 instructions and it supports x86 and x86-64 instructions sets with MMX, 3DNow!, SSE up to SSE4, AVX, AVX2, XOP and AVX-512 extensions and can produce output in plain binary, MZ, PE, COFF or ELF format. It includes the powerful but easy to use macroinstruction support and does multiple passes to optimize the size of instruction codes. The flat assembler is self-hosting and the complete source code is included.

The only difference between the various flat assembler packages is the operating system on which they can be executed. From given source each version will generate exactly the same output file, so with each of the following releases you can compile programs for any operating system.

The flat assembler g (abbreviated to fasmg) is the new assembly engine designed to become a successor of the one used by flat assembler 1. It does not have a built-in support for x86 instructions. It is a generic assembler that can be used in place of flat assembler 1 in applications where only the pure macroinstruction engine is needed instead of x86 encoder, for example when an instruction set for a different architecture is defined through macroinstructions. However it still has the ability of self-hosting, thanks to the included set of macroinstructions implementing basic x86 instructions and formats.

The following are some third-party products based on flat assembler, they are available to download from their respective websites.

Copyright © 2004-2016, Tomasz Grysztar.