On Wed, Aug 03, 2011 at 04:03:39PM -0400, Tom Lane wrote:
> The C standard specifies that signed-to-unsigned conversions must work
> like that; and even if the standard didn't, it would surely work like
> that on any machine with two's-complement representation, which is to
> say every computer built in the last forty years or so. So I don't find
> it a questionable assumption.
I had the "pleasure" of working on a Univac 1108 in about 1978 and
it was very definitely ones complement. I'm somewhat amazed to find that
the Univac 1100 series architecture and instruction set lives on to this
day. The last pure 1100 seems to be the Unisys 2200/3800 released in 1997.
Even later U1100/Exec 8 descendants appear to still exist and are still
actively supported:
http://en.wikipedia.org/wiki/Unisys_OS_2200_operating_system
So there are still ones complement machines out there. However I suggest we
pretend otherwise and continue to ignore them.
-dg
--
David Gould daveg@sonic.net 510 536 1443 510 282 0869
If simplicity worked, the world would be overrun with insects.