FPUs for small computers (Was: What to download for a PDP-8)

Ethan Dicks ethan.dicks at gmail.com
Wed Oct 17 17:25:47 CDT 2007


On 10/17/07, dwight elvey <dkelvey at hotmail.com> wrote:
>  I have a S100 board made by N* that is a math board but it
> doesn't have a FPU. It has a 2901 and some ROM chips.
>  It only has the one 2901.

Hmm... that sounds interesting - a 4-bit ALU math co-pro?  Obviously
it must be running many machine cycles to be digesting numbers a
nybble at a time.

It's not a general-purpose thing, but the Atari vector game hardware
(Battlezone, Star Wars...) has an 8-bit main CPU and a 16-bit
2901-based "math box".  It's been mentioned on the list before, but
essentially, the 8-bit CPU feeds shaps to the 16-bit math
co-processor, which does transforms to calculate the 2D vector
endpoints to render the shapes as they tumble and rotate.

-ethan



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