English Amiga Board - View Single Post - 68030 write-allocate mode

Toni Wilen · 13 August 2011, 20:25

Second time today I post this link: http://amigadev.elowar.com/read/ADCD.../node0161.html

Quick explanation: 68030 data cache always caches long aligned writes, even if destination address is supposed to be uncacheable. Following read(s) from same address come from cache, not from memory that may have been modified by some DMA device.

AFAIK this can be only fixed by using MMU to mark required memory regions as uncacheable. (if CPU is non-EC)

13 August 2011, 20:25	#2
Toni Wilen WinUAE developer Join Date: Aug 2001 Location: Hämeenlinna/Finland Age: 49 Posts: 26,518	Second time today I post this link: http://amigadev.elowar.com/read/ADCD.../node0161.html Quick explanation: 68030 data cache always caches long aligned writes, even if destination address is supposed to be uncacheable. Following read(s) from same address come from cache, not from memory that may have been modified by some DMA device. AFAIK this can be only fixed by using MMU to mark required memory regions as uncacheable. (if CPU is non-EC)