Just to chime in with more 68k nostalgia and trivia: The 68000 didn't have cache - but 68010 did.
Three whole instructions worth of cache.
"Wha...?" you might say? Tha' heck good is that? The point was that the 3-instruction cache could cache tight loops, like the kind you would use for mem-to-mem copies, which is a terribly common thing to do. I put one in my Amiga 1000 (geez, did I hack that thing...) and got about a 10% overall system performance increase.
I remember it as just one instruction plus the jump. Checking up on this now, it looks like the "cache" (actually the IR register and the prefetch register) can only hold one 16-bit instruction and a DBxx instruction.
Three whole instructions worth of cache.
"Wha...?" you might say? Tha' heck good is that? The point was that the 3-instruction cache could cache tight loops, like the kind you would use for mem-to-mem copies, which is a terribly common thing to do. I put one in my Amiga 1000 (geez, did I hack that thing...) and got about a 10% overall system performance increase.
It was neat! More lovely details here: http://www.memphisamigagroup.net/diskmags/198803/68010-kit/M...