On Sep 22, 2012, at 7:06 PM, Dave Angel <d...@davea.name> wrote: > On 09/22/2012 05:05 PM, Tim Roberts wrote: >> Dennis Lee Bieber <wlfr...@ix.netcom.com> wrote: >>> On 22 Sep 2012 01:36:59 GMT, Steven D'Aprano wrote: >>>> For non IEEE 754 floating point systems, there is no telling how bad the >>>> implementation could be :( >>> Let's see what can be found... >>> >>> IBM 360: Same as Sigma-6 (no surprise; hearsay is the Sigma was >>> designed by renegade IBM folk; even down to using EBCDIC internally -- >>> but with a much different interrupt system [224 individual interrupt >>> vectors as I recall, vs the IBM's 7 vectors and polling to find what >>> device]). >> The Control Data 6000/Cyber series had sign bit and 11-bit exponent, with >> either a 48-bit mantissa or a 96-bit mantissa, packed into one or two >> 60-bit words. Values were not automatically normalized, so there was no >> assumed 1 bit, as in IEEE-754. > > And it's been a long time (about 39 years), but as I recall the CDC 6400 > (at least) had no integer multiply or divide. You had to convert to > float first. The other oddity about the CDC series is it's the last > machine I've encountered that used ones-complement for ints, with two > values for zero. > >
Well, for what it is worth… the DEC Laboratory INstrument Computer (LINC-8, sort of a forced acronym because I believe they were built to specs issued by Lincoln Labs.) and the later DEC PDP-12 (which incorporated the LINC-8 instruction set, along with the PDP-8 basic set) also did ones-complement integer arithmetic. I never used a LINC-8, but I worked for several years around PDP-12s. (They also had a build-in CRT and a MUX'd analog-to-digital converter with CPU instructions for driving both directly.) As I remember, they maxed out at 32k (12-bit) words of RAM. I don't know when they were discontinued, but there were still some PDP-12s in use as late as 1988 when I lost track. -Bil > -- > > DaveA > > -- > http://mail.python.org/mailman/listinfo/python-list -- http://mail.python.org/mailman/listinfo/python-list
