SE/30 VRAM Capacity W/ 24 Bit Addressing? — #3

Post #3 by trag

Source Forum	68kMLA
Category	Hardware
Post Date	Thu, 1 Apr 2010 - 23:26
Original URL	https://68kmla.org/bb/threads/se-30-vram-capacity-w-24-bit-addressing.19768/

Post

Luckily, Apple derived a solution to this when it created 32-bit QuickDraw, and it is quite simple. Every time 32-bit QuickDraw access VRAM in the slot space, it uses a trap (SwapMMUMode) to temporarily switch the MMU into 32-bit mode, and when they are done, they use the same trap to switch back into 24-bit mode.

Thank you!! I had given up on ever getting an answer.

Do you remember how you learned about this? Volume of Inside Macintosh? Some other reference?