4 ms·
It's not an implementation detail, if it has to go through the system bus
by jdjebdndn 2y ago
It's not an implementation detail, if it has to go through the system bus
- chrisjj 2y agoOr off the CPU regardless, mind.
- brucehoult 2y agoGoing through the system bus IS an implementation detail. You could build a 6502-compatible CPU with a (extra [1]) 256 byte on-chip register file, and treat, for example, `0x1265` as simply a 16 bit instruction `ADC A,R18`, or `0x0791` as an x86-ish `MOV [R7+Y],A`. All binary programs would run just as they do on the 1975 6502, just a lot faster. [1] in the original 6502, the registers aren't in a register file in the modern sense, they're implemented with flip flops and all are accessible simultaneously (with wired-OR on to a bus in some cases if the decode ROM selected several at the same time)