2 Jun
2017
2 Jun
'17
9:48 a.m.
On 6/2/2017 11:26 AM, Chuck Guzis via cctalk wrote:
On 06/02/2017 07:55 AM, Al Kossow via cctalk wrote:
This begs the
question of why the CP1600 was designed that way. I fail
to believe that GI engineers were somehow less intelligent than the rest
of the population, so what happened? Upper Management dictate?
Customer demand? It would be interesting to know.
Jim
A very odd version of the PDP-11
I did some programming on it for GI in the late 70's using their
GIMINI development system and cross-development tools on their Sigma
9.
I sold a bare CP1600 chip about a year ago to a collector. "Odd" is
an
understatement. A 10-bit wide instruction word, with the upper 6 bits of
the opcode unused. Loading a 16-bit address took three words.
Also, slow, very slow, with no I/O instructions. A stripped-down
instruction set (IIRC, exclusive OR and AND Boolean ops, but no
inclusive OR). We'd examined its possible usage, but determined that
code would run slower on it than on most contemporary 8-bit CPUs.
But, for 1975, notable because it's a 16-bit monolithic CPU among a
handful of others (Fairchild 9440, MicroNova, National PACE, TI 9900)