[Simh] PDP-11 Spacewar?

[Lars Brinkhoff]

Hello,

This seems to be a Spacewar for PDP-11. Written using the PALX cross
assembler. But what kind of display is it using?

https://github.com/PDP-10/its-vault/blob/master/files/rjl/war11.3

[Johnny Billquist]

Post by Lars Brinkhoff
Hello,
This seems to be a Spacewar for PDP-11. Written using the PALX cross
assembler. But what kind of display is it using?
https://github.com/PDP-10/its-vault/blob/master/files/rjl/war11.3

Suspect it might be this:
http://www.computerhistory.org/visiblestorage/1970s-1990s/games-and-robots/arcade/

CHM have one. Not sure exactly what display it used, but it's obviously
a vector display.
Might not even have been a DEC one.

Pretty fun to see something written for an 11/20 with EAE. That was a
pretty short lived option...

Johnny

[Lars Brinkhoff]

Post by Johnny Billquist

Post by Lars Brinkhoff
https://github.com/PDP-10/its-vault/blob/master/files/rjl/war11.3

http://www.computerhistory.org/visiblestorage/1970s-1990s/games-and-robots/arcade/

Good call. I found a video on YouTube, and all the strings here

appear in the source code.

[Paul Koning]

Post by Lars Brinkhoff
Hello,
This seems to be a Spacewar for PDP-11. Written using the PALX cross
assembler. But what kind of display is it using?
https://github.com/PDP-10/its-vault/blob/master/files/rjl/war11.3

Suspect it might be this: http://www.computerhistory.org/visiblestorage/1970s-1990s/games-and-robots/arcade/
CHM have one. Not sure exactly what display it used, but it's obviously a vector display.

I don't think so. Look at function LINE, it's a typical "step through the dots that make up a vector" algorithm. Not Bresenham I think but something along those lines.

Pretty fun to see something written for an 11/20 with EAE. That was a pretty short lived option...

Does SIMH support EAE?

paul

[Mark Pizzolato]

Post by Paul Koning

Post by Johnny Billquist

Post by Lars Brinkhoff
Hello,
This seems to be a Spacewar for PDP-11. Written using the PALX cross
assembler. But what kind of display is it using?
https://github.com/PDP-10/its-vault/blob/master/files/rjl/war11.3

http://www.computerhistory.org/visiblestorage/1970s-1990s/games-and-
robots/arcade/
CHM have one. Not sure exactly what display it used, but it's obviously a
vector display.

I don't think so. Look at function LINE, it's a typical "step through the dots that
make up a vector" algorithm. Not Bresenham I think but something along
those lines.

Post by Johnny Billquist
Pretty fun to see something written for an 11/20 with EAE. That was a pretty
short lived option...

Does SIMH support EAE?

Yes. There is a KE11 device which Bob wrote.

- Mark

[Lars Brinkhoff]

This post might be inappropriate. Click to display it.

[Johnny Billquist]

Post by Paul Koning

Post by Lars Brinkhoff
Hello,
This seems to be a Spacewar for PDP-11. Written using the PALX cross
assembler. But what kind of display is it using?
https://github.com/PDP-10/its-vault/blob/master/files/rjl/war11.3

Suspect it might be this: http://www.computerhistory.org/visiblestorage/1970s-1990s/games-and-robots/arcade/
CHM have one. Not sure exactly what display it used, but it's obviously a vector display.

I don't think so. Look at function LINE, it's a typical "step through the dots that make up a vector" algorithm. Not Bresenham I think but something along those lines.

It don't look so much like stepping through dots, as small sections of
line. It has a step value, which is 200, and it finds which is the
smaller of delta x and delta y, and apply the 200 to that one, and
figures out how much the other axle should change for each step, and
then it loops through setting the CSR X and Y to these discrete values.

But maybe the resolution in the screen is so high that 200 really is
just one pixel?

The code is written in a little cryptic fashion, by the way. It takes
some reading. Not to mention the lack of comments...

Johnny

[Adam Sampson]

Post by Lars Brinkhoff
This seems to be a Spacewar for PDP-11. Written using the PALX cross
assembler. But what kind of display is it using?
https://github.com/PDP-10/its-vault/blob/master/files/rjl/war11.3

That's a (previously unknown?) version of Galaxy Game, one of the very
earliest arcade games! Compare with the PALX listing and schematics
here:
https://code.google.com/archive/p/galaxygamepdp11/downloads

Bitsavers has some photos of the hardware at CHM too:
http://bitsavers.informatik.uni-stuttgart.de/pdf/stanford/galaxyGame/

There's a driver for this hardware in MAME (galgame); it'd be
interesting to bring up this version and see how it differs.

[Lars Brinkhoff]

Post by Adam Sampson
There's a driver for this hardware in MAME (galgame); it'd be
interesting to bring up this version and see how it differs.

The accesses to the display hardware registers have been stubbed out. I
suspect this was an attempt by Ron Lebel (at the MIT Logo group) to port
the game to their one-off vector display system made by Tom Knight.