Path: utzoo!utgpu!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!knuth!mjbtn!raider!elgamy!elg
From: elg@elgamy.raidernet.com (Eric Lee Green)
Newsgroups: comp.sys.amiga.advocacy
Subject: Re: 680x0 vs 80x86
Message-ID: <00678001178@elgamy.raidernet.com>
Date: 27 Jun 91 04:39:38 GMT
References: <1154@stewart.UUCP> <92@ryptyde.UUCP> <4671.tnews@templar.actrix.gen.nz>
Organization: Eric's Amiga 2000 @ Home
Lines: 18

From article <1154@stewart.UUCP>, by jerry@polygen.uucp (Jerry Shekhel):
> jbickers@templar.actrix.gen.nz (John Bickers) writes:
>>    It's usually because if you have a split cache you break programs
>>    that use self-modifying code.
> Doubtful, John, since every OS in existence treats code as data when it
> loads it into memory for execution.

Note that AmigaDOS takes that into account, for the 68030/68040 class
machines. Flushes the program cache so that the new data is loaded into it.
MSDOS, of course, does nothing of the sort. Which is why MSDOS-based
machines have an integrated code/data cache, which is less efficient than a
split cache (since data generally has a less than 50% hit rate, and data
accesses would keep kicking program cache lines out of memory... whereas
code has 90% or better hit rate with decent cache sizes).

--
Eric Lee Green   (318) 984-1820  P.O. Box 92191  Lafayette, LA 70509
elg@elgamy.RAIDERNET.COM               uunet!mjbtn!raider!elgamy!elg