4 ms·
The 8080 instruction set opcodes have logical bit patterns, so you can identify the operation and operands through bit masking instead of requiring a huge LUT.
by slily 3y ago
The 8080 instruction set opcodes have logical bit patterns, so you can identify the operation and operands through bit masking instead of requiring a huge LUT. Beyond that you can simplify a lot by sacrificing timing accuracy.
- zabzonk 3y agoyou can also write one using a 256-byte switch, which ain't so big. i wrote an 8080 emulator in fortran77 on a dec10 that way, back in the 1980s. but of course size wasn't an issue. it did prove to be quite portable - to vax and ibm vm/cms. we used it for teaching assembler programming.