HLRnet.com:
Freeware
programming utilities: Assembler
Programming freeware: Assembler tools and sources
- Easy Code is the visual
assembly programming environment made to build 32-bit Windows
applications (now supporting Unicode and multiple languages).
http://www.easycode.cat
http://www.freewarefiles.com/Easy-Code-GoAsm_program_27016.html - DownloadMore InformationNASM - The Netwide Assembler
NASM is an 80x86 assembler designed for portability and modularity. It supports
a range of object file formats including Linux a.out and ELF, COFF, Microsoft
16-bit OBJ, Win32/64, and Apple Mach-O. It will also output plain binary files.
Its syntax is designed to be simple and easy to understand, similar to Intel's
but less complex. It supports all currently known opcodes, and has advanced
macro capability. It includes a disassembler as well.

http://freshmeat.net/projects/nasm - The flat assembler is a fast and efficient
self-assembling 80x86 assembler for DOS, Windows, and Linux operating
systems. It supports all 8086-80486/Pentium instructions with MMX, SSE,
SSE2, SSE3, and 3DNow! extensions and x86-64 (both AMD64 and EM64T)
instructions. It can produce output in binary, MZ, PE, COFF, or ELF
format. It includes the powerful but easy-to-use macroinstruction
support, and does multiple passes to optimize the instruction codes for
size. The flat assembler is entirely written in assembly language.
http://freshmeat.net/projects/fasm/
http://www.flatassembler.net/ - MikeOS is an operating system for x86 PCs,
written entirely in assembler. It's not intended to to become a
fully-fledged general purpose OS. Instead, it's designed for learning
basic OS design and x86 assembly language. Consequently, it runs in
16-bit mode (for BIOS access) and has very low system requirements. It
features rudimentary DOS compatibility.
http://freshmeat.net/projects/mikeos/ - Yasm is a complete rewrite
of the NASM assembler. It currently supports the x86 and AMD64
instruction sets, accepts NASM and GAS assembler syntaxes, outputs
binary, ELF32, ELF64, COFF, Mach-O (32 and 64), RDOFF2, Win32, and
Win64 object formats, and generates source debugging information in
STABS, DWARF 2, and CodeView 8 formats.

http://freshmeat.net/projects/yasm - Easy Code for GoAsm: Visual assembly programming environment made to build 32-bit Windows applications.
http://www.freewarefiles.com/Easy-Code-GoAsm-V_program_27016.html
http://www.easycoder.org/
- Easy Code for Masm
Visual assembly programming environment made to build 32-bit Windows applications.
http://www.freewarefiles.com/Easy-Code-Masm-V_program_23623.html
http://www.easycoder.org/