Yes, that would be Carl’s “day to day” blog (http://rescue1130.blogspot.com/).
He is also on the list, lurking in the background. Carl, are you there?
Ken Shirriff has also several deeply researched blog articles on specific AGC
topics (righto.com).
Mike has some very interesting posts on his
On 2019-Mar-26, at 9:28 AM, Noel Chiappa via cctalk wrote:
>> From: Ben Bfranchuk
>
>> Now they seem to have have found a SCRAPPED Apollo guidance
>> computer and am rebuilding the missing pieces.
>
> Wow. What a great site (and that guy has mad skills, everything from
> repairing old Teletypes,
> From: Ben Bfranchuk
> Now they seem to have have found a SCRAPPED Apollo guidance
> computer and am rebuilding the missing pieces.
Wow. What a great site (and that guy has mad skills, everything from
repairing old Teletypes, through designing boards, to repairing analog
stuff).
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
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
On Mon, Mar 25, 2019 at 1:26 AM Kyle Owen via cctalk
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
, March 25, 2019 12:26 AM
To: General Discussion: On-Topic and Off-Topic Posts
Subject: Re: PDP-8 signed overflow detection
Overflow can be summarized in a few ways, such as: (sign of arg_a XOR sign
of arg_b == 0) AND (sign of arg XOR sign of result == 1)
or, less intuitively, the carry into the sign
Overflow can be summarized in a few ways, such as: (sign of arg_a XOR sign
of arg_b == 0) AND (sign of arg XOR sign of result == 1)
or, less intuitively, the carry into the sign != the carry out of the sign.
My first inclination was to try the XOR approach, as that was most
intuitive to me. Using
I thought about it during the bus ride home. I don't
think I got it right. I'll try again after the kids
go to bed.
/P
On Thu, Mar 21, 2019 at 04:37:26PM +0100, Pontus Pihlgren via cctalk wrote:
> Hmm, sounds like a fun thing to figure out. How about this for a start.
> Naive, written five
Hmm, sounds like a fun thing to figure out. How about this for a start.
Naive, written five minutes before I have to catch my bus, untested.
I hope I understood the problem at least :)
/P
SATSUM,0
CLA CLL
TAD I SATSUM
ISZ SATSUM
TAD I SATSUM
ISZ SATSUM
What is the shortest subroutine on a PDP-8 which will add two variables in
RAM and return the saturated sum (that is, returning 2047 or -2048 upon
overflow, otherwise the sum) in the accumulator?
Kyle
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