On 04/12/2018 02:45 AM, Chuck Guzis via cctalk wrote: > 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. >
Signed 8 bits would be -128 to +127. bill
