PDP-8 signed overflow detection - Apollo guidace computer

ben bfranchuk at jetnet.ab.ca
Tue Mar 26 02:02:43 CDT 2019


On 3/25/2019 7:27 PM, Charles Dickman via cctalk wrote:
> On Mon, Mar 25, 2019 at 1:26 AM Kyle Owen via cctalk <cctalk at classiccmp.org>
> wrote:
> 
>>
>> All this to fix a ~45 year old bug in Spacewar! where a ship's velocity
>> overflows, causing the ship to "bounce" off of nothing.
>>
>> I would have figured it was bouncing off a chunk of dark matter.
> 
> Cool stuff! PDP-8 programming always seems a bit like puzzle solving.
> 
> Kyle

Some times the hardware is more fun than the software.
I got looking at a BLOG I had forgotten about.
First they planned on Emulating a IBM 1130
Later they found a real IBM 1130 in the middle of now where.
Now they seem to have have found a SCRAPPED Apollo guidance
computer and am rebuilding the missing pieces.

http://rescue1130.blogspot.com/
Ben.


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