14 May
2015
14 May
'15
8:46 a.m.
On 05/13/2015 08:37 PM, Eric Smith wrote:
I'm pretty sure this is true, the amount of logic in the
machine is not that much more than similar 12-bit CPUs.
The ALU had to handle both ones-complement and two's
complement operations, and the instruction decode logic
needed to be about double, but the data paths logic could
all be done with one implementation.
I did use the PDP-12 at Washington University, and it was a
real nice machine!
Jon
From the web
page:
"so it actually has two processors"
Is that true? I haven't had time to make a detailed study of the
PDP-12 logic design, but my understanding was that unlike the LINC-8,
which basically was two separate processors mashed together, the
PDP-12 was a single integrated processor with two modes (PDP-8 and
LINC). I was told that there were some commonalities that were taken
advantage of, such that merging it resulted in reduction of the total
logic necessary as compared to the LINC-8.