Hi! On Fri, Nov 10, 2000 at 04:50:31PM +0100, Xavier Joubert wrote: > > Sorry, but why is it that big? On my Milan (with 80 Megabytes of RAM), > > the MMU tree installed by TOS just needs a few kilobytes, as it uses > > "invalid" upper level pointers for areas where there isn't any memory at > > all and accesses would trigger an access fault anyway. Or to phrase it > > differently, it only uses page level descriptors for areas where there > > is (partly) physical RAM, ROM or I/O registers. And it uses indirect > > page level descriptors where possible. > > Because there are no "early termination descriptor" on the 68 060. We > don't want the MMU to return any bus error. As in the original Falcon, > this job is devoted to the hardware (timeout). But there's transparent translation. That should fit just perfectly for your task, i.e. letting hardware handle accesses to areas not connected to RAM, ROM or known I/O. And for areas covered by transparent translation, there's no need to have a full three-level MMU tree, thus saving a lot of memory. Ciao Thomas -- Thomas Binder (Gryf @ IRCNet) gryf@hrzpub.tu-darmstadt.de PGP-key available on request! binder@rbg.informatik.tu-darmstadt.de Vote against SPAM: http://www.politik-digital.de/spam/
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