23 Sep
2015
23 Sep
'15
7:54 a.m.
On 2015-09-23 16:43, Paul Koning wrote:
As far as I can remember, the C standard still do not require that the
computer uses two complement. So you can actually get away with a C
compiler that uses one complement. But much actual code will probably
break, because they make way more assumptions than the standard actually
provide...
Johnny
On Sep 23, 2015, at 10:30 AM, Jay Jaeger
<cube1 at charter.net> wrote:
On 9/23/2015 9:10 AM, Mouse wrote:
>> I am 100% certain, for example, that it would be possible to come up
>> with a C compiler for a 40K IBM 1410, which is in the set you
>> describe.
>
> Possible? Sure. But it would be difficult; you would need to simulate
> a binary machine - C has a whole bunch of stuff that is defined to
> operate "as if" certain things are stored in binary.
Worse yet, two's complement binary. At least nowadays. Which makes me suspect that
there had to be some shortcuts taken when C was implemented on the CDC 6000 series.
(Interestingly enough, if you ignore that little detail, it isn't terribly hard to
write the skeleton of a 6000 code generator back-end for GCC...)