Raven. A homemade Atari-like computer

[agranlund]

Got struck with an idea while driving home from work and had to try it..

It's not a crazy performance bump, but for only a few lines of code it's not a bad free performance boost.
For now only applied on the SVGA driver but I should be able to make this global so it effects ET4000 and Mach as well.
There are further optimisations which could be made in the same spirit but requires more work.

Cirrus GD5434 now vs previous driver:

gd5434_ci_vs_cp.png (898.67 KiB) Viewed 44 times

gd5434_ci.png (901.7 KiB) Viewed 44 times

gd5434_ci_vs_cp_kronos.png (562.14 KiB) Viewed 44 times

[PhilC]

@agranlund that's a pretty good increase for just a few lines of code.

[agranlund]

@agranlund that's a pretty good increase for just a few lines of code.

Yep, I realised if I tag the vram pages as cache-inhibited-imprecise to take advantage of the storebuffer fifo then the cpu can keep doing a little bit of meaningful work while an ISA transfer is happening.