Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!amdahl!oliveb!amiga!jimm
From: jimm@amiga.UUCP (Jim Mackraz)
Newsgroups: comp.sys.amiga.tech
Subject: Re: SetCPU and the MMU
Keywords: SetCPU MMU 68851
Message-ID: <3314@amiga.UUCP>
Date: 7 Feb 89 19:35:37 GMT
References: <10642@well.UUCP>
Reply-To: jimm@cloyd.UUCP (Jim Mackraz)
Distribution: comp
Organization: Commodore-Amiga Inc, Los Gatos CA
Lines: 36

In article <10642@well.UUCP> sjm@well.UUCP (Stephen Moehle) writes:
)
)I recently obtained SetCPU v1.4.  My thanks to Dave Haynie for the code to
)map the ROM into fast RAM using the MMU.  I finally understand why my own
)attemps to use the MMU were failing.  However (there is always a "however",
)isn't there?), when I use the FASTROM option I get some strange results.
)Every 20 to 30 keystrokes, the last key will be repeated 10 to 15 times.
)Can anyone tell me why this is?  Is there any way to fix it?  Other than that
)everthing seems to work.  Some things are faster.  Most are not.  I have a
)rev 4.2 B2000 with an A2620.  Thanks.

You have a Cherry keyboard, right?  (The one with the function keys
the same size as the escape key.)

There is a processor speed dependency in the keyboard interrupt handler,
when in fast ram it runs too fast.  Oops.

There are two patches available on bix.  One, by Kodiak, replaces the keyboard
interrupt handler with a copy in chip memory, which runs slower.  We
will use this setup as a test for a proper fix to the problem (testing it in
fast ram, of course).

Jez Sans, famed game guy, wrote a much smaller patch which hacks in a jump to
a piece of code with a delay in it.  Nice and dirty, but works fine and is smaller.

I don't know how you can get these other than on BIX or from whomever you 
got SetCPU in the first place.  Since now everyone with an MMU will want
both now that you mention SetCPU, perhaps you should be the one to make them
available. ;^)

	jimm
-- 
Jim Mackraz, I and I Computing	   	"Like you said when we crawled down
{cbmvax,well,oliveb}!amiga!jimm          from the trees: We're in transition."
							- Gang of Four
Opinions are my own.  Comments are not to be taken as Commodore official policy.