On Fri, Apr 22, 2016 at 10:03 PM, ben <bfranc...@jetnet.ab.ca> wrote: >> Not exactly bit-slice, but how about the National IMP-16 chip set?
It's bit-slice. The RALU chips were four bits wide, and were used in at least three different processor architectures, the IMP-4, IMP-8, and IMP-16. (Despite the similarity of naming, the actual architectures aren't very similar.) The CROM (Control ROM) could be custom microcoded for other architectures. > Too Early , Not too early to be bit-slice. The DEC PDP-6 was implemented as bit-slice, but not with ICs. > Too Slow , It looks amazingly slow now, but compared to other things available in 1974, it was reasonable. > Too $$$ is my guess. Actually it was cheap, again by comparison to contemporary things. > With out the 6800/6502 8080/Z80 price wars, how much would a 8 bit > CPU be in the late 70s? $75? $395 for an 8080 in 1974. Under $20 for most 8-bitters by the end of 1979.
