Using the F18A GPU

[Tursi]

The F18A includes a 100Mhz TMS9900 16-bit CPU in it that executes from VRAM and has direct access to all video memory.

 

I thought I'd do a quick sample here - this is a mandlebrot generator for bitmap mode that I wrote some years ago for the TI. On the TI, it generates the screen in roughly 30 seconds. On the GPU, it takes 3.

 

Since the code was entirely running on the GPU, I decided to port to ColecoVision - all that is needed is to load the binary into VRAM, unlock the F18A, and tell it to go. All included here. 

 

If you don't have an F18A - this code won't do anything, not even tell you. If you do (including Phoenix), you'll get the picture.  Let me know if it works for you!

mandlegpu.zip

[alekmaul]

Nice !

I will use your rom to complete my F18A compatibility in EmulTwo. Currently, I only have a dark screen

[Tursi]

17 hours ago, alekmaul said:

Nice !

I will use your rom to complete my F18A compatibility in EmulTwo. Currently, I only have a dark screen

Well, 12 people have downloaded it and nobody has said it works, so I dunno.

 

[alekmaul]

tada !!!!

I need now to investigate why I do not have the same image.

[Tursi]

Ah, pretty close! What are you using for your 9900 core? Looks like math. Pleasing pattern though

 

I have a CPU test here that tests every instruction -- though you'll need to adapt the init and output code a little bit to run on the F18A. It's not comprehensive, but it found bugs in Classic99 back in the day. Maybe it'll help?

https://github.com/tursilion/classic99/blob/main/tests/99test2.txt

 

Edited October 28, 2023 by Tursi

[alekmaul]

Hi Tursi, Thanks a lot. I will try to adapt it for colecovision.
I also need to check the math function. It is perhaps a sign/unsign issue in some vars.

[alekmaul]

I think I got it

some bad condition jump tests

 

[Tursi]

Very nice!