18 bit CPU; was: Speed now & then

Jay Jaeger cube1 at charter.net
Sun Apr 15 18:47:19 CDT 2018



> On Apr 15, 2018, at 09:44, Bill Gunshannon via cctalk <cctalk at classiccmp.org> wrote:
> 
> 
> 
>> On 04/15/2018 02:28 AM, r.stricklin via cctalk wrote:
>>> On Apr 14, 2018, at 4:00 PM, Bill Gunshannon via cctech wrote:
>>> 
>>> I'm familiar with Univac's having worked on the 1100 many moons ago,
>>> But look at the line above my comment:
>>>  "you assume that a char is 8 bits, with a signed char having a range
>>> of +/-255".
>>> 
>>> An 8 bit signed char has the values -128 to +127, as I stated.  even a 9 bit
>>> signed char would not be +/-255 but -256 to +255.
>> Doesn't the 1100 use one's complement? -0 != 0, so AFAICT it's still +/-255.
>> 
> Can't remember that.  It's over 30 years since my 1100 days.
> 
> I do remember it wasn't an ASCII machine, however.  good ole Fielddata.
> 
> bill
> 

Yes, the Univac 1100 series were one’s complement (had brief experience as a student with 1108 and 1110 from 1969 to 1975)

Sent from my iPad


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