Aasm is an advanced modular assembler designed to support several target architectures. It has been designed to be easily extended. Its global architecture takes advantages of dynamic libraries to provide input, assembler and output modules. The input module supports Intel syntax (like nasm, tasm, masm, etc.). The x86 assembler module supports all opcodes up to P6 including MMX, SSE and 3DNow! extensions. F-CPU and SPARC assembler modules are under development. Several output modules are available for ELF, COFF, IntelHex, and raw binary formats. Advanced features include symbol scopes, an expressions engine, big integer support, macro capability, and numerous and accurate warning messages (over 300).
Flat Assembler is a fast and efficient self-assembling 80x86 assembler. It supports x86 and x86-64 instruction sets with MMX, 3DNow!, SSE up to SSE4, AVX, AVX2, and XOP extensions. It can produce output in binary, MZ, PE, COFF, or ELF format. It includes powerful but easy-to-use macroinstruction support and does multiple passes to optimize the instruction codes for size. It is written entirely in assembly language.
The HLA Standard Library was developed to support the High Level Assembler (HLA), but could be used with other assemblers or higher-level languages if the necessary headers were developed. It supports 32-bit versions of Windows, Linux, Mac OS X, and FreeBSD, and is written entirely in HLA. It includes the following modules: args, arrays, bits, chars, console, conversions, cset, date, environment, exceptions, file class, file I/O, filesys, lists, math, memory-mapped files, patterns, RNG, stderr, stdin, stdout, strings, tables, time, timer, zstrings, sockets, threads, and blob. An automated test suite is included.