Decodey spec - Atmelfan/C204 GitHub Wiki
- instruction[15..0], instruction to be executed
- asel[3..0]: selects A register
- bsel[3..0]: selects b register
- intermediate[7..0]: intermediate data
- muxsel: selects between A register or intermediate data
- op[3..0]: ALU operation
- extended: Fetchy should ignore next word
1 instruction = mppp-iiii-aaaa-bbbb
asel = aaaa
bsel = bbbb
intermediate = iiii & aaaa
op = 0ppp
muxsel = m
extended = '1' when ppp = JMP else '0'