Welcome to my article on Code Coloring, the totally new thing I, Appledog, invented on January 31st, 2006 at 4:35pm while chatting on discord.

So basically I was thinking about how to optimize the hot path and cam.k1 said, “How does the 65816 get away with only having 3 registers (A,X,Y) while it's competitor the m68k has 16”

In the ensuing discussion, I said you don't need that many registers. Then when hypothesizing how many you need, I came to the idea of 8 registers. Then without even realizing what I said, I said

Appledog — 4:23 PM You don't really need 16 registers Actually it would be a lot simpler to have standard registers.. like an ADD instruction automatically adds A and B and puts the result in C In that sense, I am thinking, instead of registers, you could design a meta-CPU with meta execution-contexts. Such as ABXY or ABCXYZ; just 4 or 6 contexts, maybe with a stack and flags (8 total).. Hmm!

calc84maniac — 4:28 PM simpler CPU design for sure, but compiler designers will hate it

Appledog — 4:28 PM And operations require values to be in certain registers. Ok so given that variable assignments are faster than array accesses you could probably set up a mini cache or stack with actual variables. Well the thing is, I think programmers have gotten a bit lazy Everyone expects certain kinds of architecture If you could guarantee that operations used certain registers you could eliminate at least two IFS and a memory op per cycle in an emulator You'd double the speed So you have four execution contexts And four versions of LOAD for each register– thats 32 LOADs, 32 STOREs, 32 ADDs, 32 SUB, etc Its a lot of opcodes but it would be way faster. All you are really doing is unrolling the register encoding on an opcode It actually might make things clerarer and easier to pipeline because you can execute code in different contexts out of order, with guaranteed non-interference Like automatically enabling the cpu to multithread your code omg did you hear what I just said

Appledog — 4:36 PM This is amazing. Its code coloring! I invented code coloring!