ZASM is a 2 pass assembler for Zilog's 8-bit CPU Z80.
Supported platforms: Unix-style OS, e.g. MacOS X, Linux, BSD.
Special support for ZX Spectrum emulator file formats.
Binary or intel hex file output.
SIMACH is a Emulator Development Kit. The goal is to develop a IDE that'll allow a developer to easily write and debug a highly portable emulator, automaticly generating code to the destination plataform.