Amiga AGA RTG

[itix]

The higher the bitdepth the more of that 2MB it will use up. Therefore if you have FAST RAM it follows that you can use a higher bit depth because more graphics memory is available due to most of the stuff that previously was in graphics memory is now in FAST RAM instead.

AGA still couldnt use more than 8 bit planes at once. But AGA could be wrapped inside RTG where offscreen bitmaps were allocated from fast ram and chip ram was reserved for screens. Unfortunately manipulating planar bitmaps by CPU is insanely slow, 8bit AGA screens are insanely slow, not to mention insanely slow chip ram bus.

[KThunder]

it would probably be possible to use rtg type drivers to get aga to do stuff it wasnt meant to do. like ham or sham workbench. pcg stuff. it probably wouldnt be hugely fast and it would slow the cpu down though.

[alexatkin]

AGA still couldnt use more than 8 bit planes at once. But AGA could be wrapped inside RTG where offscreen bitmaps were allocated from fast ram and chip ram was reserved for screens. Unfortunately manipulating planar bitmaps by CPU is insanely slow, 8bit AGA screens are insanely slow, not to mention insanely slow chip ram bus.

Sounds like that is what this does
http://aminet.net/package.php?package=util/boot/fblit.lha only it doesnt use RTG its patching the OS directly instead.

[KThunder]

fblit and ftext use the cpu to blit stuff instead of the blitter since it is faster that way on newer cpus