Multi-platform assembler I wrote in 1989-1994 and then updated (supports Z80 and 6502 and 8086, ST6 MCU, and partly 8051 and ARM from Archimedes)

Can generate BIN and/or HEX (intel) files from a single source, or an object (Lattice object file format, COFF, ELF, OBJ) file to be linked together to other files or libraries.