AMD bit-slice machines
ard at p850ug1.demon.co.uk
Sat Dec 31 15:22:32 CST 2005
> IIRC the Three Rivers PERQ was also a 2901 based design.
Not any PERQ that I've seen (and I think I've seen all models).
The classic PERQs (1, 1a, 2T1, 2T2, 2T4) used 74S181 ALUs and 256 nybble
RAMs for the registers (yes, 256 CPU registers).
The sequencer was an AMD 2910, which, of curse, is from the same family
as the 2901. But the 2910 is not IMHO a true 'slice' in that it can't be
extended to <n> bits. It's a 12 bit microcode sequencer (and all PERQs
apart from the 1 had 16K of control store, so they had to extend the
sequener address by a circuit kmown to all PERQ fanatics as the '2 bit
kludge', pun totally intentional). The PERQ ethernet interface and hard
disk cotnrollers also used 2910 sequencers with PROMs as the control store.
The PERQ 3a (AGW3300) was a 68020-based machine. The graphics processor
used a pair of 29116 data path chips (one to calculate addresses, one to
do the data processing) along with a very simple sequencer built from TTL.
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