11 Sep
2015
11 Sep
'15
11:47 a.m.
On 9/11/2015 8:39 AM, Johnny Billquist wrote:
On 2015-09-11 16:36, Noel Chiappa wrote:
WHile I agree that the PDP-11 is a wonderful architecture, it really is
a few bits short of perfect, both for addressing, and for opcode
allocation.
NOW if the had made the PDP 11 - 18 bits I think we could have had a
winner. It is the loss of two address bits that is the problem with 16
bits.
From: Jon
Elson elson
I actually LIKED the PDP-11 architecture quite a
LOT, but the
limited
memory was a big killer.
The good thing about the PDP-11 was the 16-bit word size. (It resulted in
what's probably the most elegant architecture, in bang/buck terms, of all
time.) The bad thing about the PDP-11 was the 16-bit word size. (For the
reason you point out.) The is obvious when you look at the EIS and FPP
extensions, which could
not retain the general instruction layout format because of a lack of bits.
Too bad we got the 8086 rather than PDP-11 style (simplified design?)
for 8/16 bit CPU.
Johnny
Ben.