3 ms·

Surely it's to make it simpler to implement?

• benj111 4y ago
  12bit instructions would be easier (I think?) If you're inplementing it in software. If you're doing hardware then you're either making the 256b memory 50% bigger or adding logic. Plus you need extra transistors to decode the longer instruction but you don't need to deal with the context switch of switching between instructions and data.
  • danielmarkbruce 4y ago
    Why would 12 bit be easier? It's written in C. For any given opcode you can just do a direct comparison in c to a char type. It would be easier to enter the instructions in text and the program read it, it would be easier to compare. I could easily be missing something here, but any time you have to chose between a nice round single byte and something else in c, it sounds like extra work to choose something else.
    • benj111 4y ago
      To me the tradeoff is mask and shift / bitfield v go get instruction, this instruction relies on data, go get the data, now complete the instruction. It seems to me that would add complication, more so than a weird width. I suppose you could conceptualise an instruction data pair as one 16 bit instruction.
      • danielmarkbruce 4y ago
        I see your point, I think I agree with you on second thought.