This is an article what appeared in Practical Electronics magazine September 1977 through June 1978 on building the "PE Champ" 4040 microcomputer. The file "chomp.asm" is source for the firmware listed in part 6 of the article edited to conform to the AS Macroassembler syntax.
jim11662418/champ-4040-microcomputer
"Practical Electronics" magazine article on building "Champ" 4040 microcomputer
Assembly