On 2018-04-12 7:48 AM, Bill Gunshannon via cctalk wrote: > > > 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" ...
Apple also used this extension in their Mac C compilers. >> (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. Yes, but Chuck was describing the Univac, where char is a 9-bit type, and a signed char is 1 sign bit and 8 magnitude bits, giving +/- 255. --Toby > > bill >
