1 Mar
2015
1 Mar
'15
3:05 p.m.
On 01/03/15 6:42 AM, Johnny Billquist wrote:
On 2015-03-01 06:14, Jon Elson wrote:
Studying the CDC 6000 instruction set (through the Grishman book) really
gives me the impression one's complement would be quite a headache to
use correctly.
--Toby
On 02/28/2015 04:59 AM, Johnny Billquist wrote:
...
The ones and twos complement is the most interesting part. I suspect
that is because they really had decided that twos complement was the
future. However, the DEC 18-bit series really started with the PDP-1,
and all follow on machines were somewhat backwards compatible, and the
PDP-1 was actually a ones complement machine. The only one DEC built
that way. So all followon 18-bitters would have to keep the capability,
I guess. Not that Unix was ever written in B anyway, but I
believe that B did
>> exist for the PDP-7.
>
I looked up the instruction set of the PDP-7, ghastly little machine,
basically
a PDP-8 extended to 18 bits. ...
Johnny