Quote:
Originally Posted by saimo
Just a general note: the MMU slows down memory accesses a bit (depending on the MMU type, on how it's programmed and what it is asked to do); therefore, if not needed to get the hardware to work properly and/or for other functional requirements (e.g. detecting memory hits, remapping the Kickstart ROM to FAST RAM on boards which can't do that automatically, etc.), one should evaluate whether MMU usage is actually beneficial.
Personally, I wouldn't use it just to remap the vectors table in FAST RAM.
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Yes, I have explained this (several times before). For 020-030 systems don't enable the MMU unless there is good reason to do this. Using the VBR imposes no performance penalty but the MMU does.
Also, even when there is a good reason to use the MMU keep in mind that how the MMU is configured can vary significantly in performance:
https://eab.abime.net/showthread.php?p=1303345
For 040-060 systems the MMU must be enabled to manage the Copyback and Non-Cache modes for the complete Amiga memory map. But there can still be compatibility problems with the "Complex" Zero page solution as noted above.
Note: The RemapZero tool included with TurboMMU040+ uses the simple "Ad Hoc" method (so it remaps the Zero page and nothing else).