On 04/11/2018 06:38 PM, Chuck Guzis via cctalk wrote: > On 04/11/2018 02:48 PM, ben via cctalk wrote: > >> I have a nice 18 bit cpu here, with only a few hardware bugs. >> Hmm would it work better if I change that around ideas. >> >> Care to point to a nice 18 bit version of unix or C. >> BTW The cpu has a frame pointer S but no S++ --S operations >> so pushing and popping wild data is not a option. > > Well, the Univac 1100/2200 series mainframes ran V7 Unix--and they're > 36-bit machines, so probably not far from your 18-bitter--and they're > ones' complement machines. > > Univac called it "SX1100", so you have a search term.
Remarkably, Unisys keeps a lot of old documentation around. Here's the reference manual for their "C" on th 1100: https://public.support.unisys.com/2200/docs/cp14.0/pdf/78310422-011.pdf Looks pretty much like standard C until you get into the minutiae, such as "A character constant is 1 to 4 characters" and page 4-4 "Data Types" (9 bit characters and 36 bit ints and 18 bit short ints). So, it should be pretty straightforward unless you assume that a char is 8 bits, with a signed char having a range of +/-255. --Chuck
