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References: Your message of "Fri, 18 Apr 1997 21:36:54 +0100"
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Date: Sat, 19 Apr 1997 12:26:26 +0100
To: KATO Takenori <kato@eclogite.eps.nagoya-u.ac.jp>
From: Bob Bishop <rb@gid.co.uk>
Subject: Re: kern/3292: Cyrix 486 performance problem
Cc: freebsd-bugs@freefall.freebsd.org
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At 4:24 +0100 19/4/97, KATO Takenori wrote:
>I read initcpu.c and compared it to old locore.s, then I found a
>solution of Cyrix 486 CPU cache.  That is just do:
>
>	Delete cache disable code in init_486dlc().
>
>1. BIOS on old motherboards may not initialize registers of Cyrix
>   486.  Thus, CPU cache is not enabled at reset time.
>2. BIOS on newer motherboards initialize registers of Cyrix 486.  Thus,
>   CPU cache is enabled by BIOS.
>
>In case 1, usere should recompile with CYRIX_CACHE_WORKS to enable CPU
>cache, because neither BIOS nor FreeBSD kernel enable it.  In case 2,
>BIOS enables CPU cache and FreeBSD kernel doesn't disable it, even
>though CYRIX_CACHE_WORKS is not set.

I think that would do it. I suspect that with these DX2 parts the cache is
on by default rather than being turned on by the BIOS (as it would have to
be for SLC/DLC), but it amounts to the same thing.


--
Bob Bishop              (0118) 977 4017  international code +44 118
rb@gid.co.uk        fax (0118) 989 4254  between 0800 and 1800 UK