I was wondering how FPU unit works on ATARI. I can only guess that while $A000, A-line instructions used for graphics, some kind of $F000, F-line instructions possibly used for FP maths?
I have only a limited info, and that is on h/w register.
I can imagine some operands are written to a h/w register, then main processor is stalled, and only resumed to fetch maths result from another h/w register. The idea is that FPU get the result computed faster than the main processor, correct?$FFFA40 - status register
$FFFA40 - command register
$FFFA40 - condition register
$FFFA40 - operands regsiter
How could I assemble a very simple FPU DIY kit for STFM (ideally mimicking MC68881). I am no hardware talent, but with some guidance I would like to give it a try.