The Quick C-- compiler is an experimental implementation of the C-- language. C-- is intended to be a "portable assembly language" that can be used as a target language by compiler writers. C-- features a simple C-like core and support for garbage collection and exception handling.
An almost ISO C compatible C compiler that produces binaries for 6502-based computers. Targets that are supported out of the box are: Apple ][, Atari 8-bit machines, Commodore C64/C128/C16/C116, Commodore Plus/4, Commodore 600/700, GEOS for C64, and Lynx. The package includes a complete suite of assembler development tools (assembler, linker, archiver) which allows mixing of C and assembler code.
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.
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.
WLA DX is yet another macro assembler that can program the GB-Z80, Z80, 6502, 65c02, 6510, 65816, HuC6280, and SPC-700 CPUs. Included in the package there is a GB-Z80 disassembler and few converters. WLA DX was initially programmed to compile ROM images for Gameboy, but nowadays it can also patch existing ROM images with code, and even compile program files and ROM files for other CPUs like the NES-6502, C64-6510, and SNES's SPC-700.