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Path: utzoo!decvax!linus!gatech!gitpyr!kpk
From: kpk@gitpyr.UUCP (Kevin P. Kleinfelter)
Newsgroups: net.micro.amiga
Subject: RE:Memory management w/o MMU
Message-ID: <1147@gitpyr.UUCP>
Date: Fri, 6-Dec-85 10:14:55 EST
Article-I.D.: gitpyr.1147
Posted: Fri Dec  6 10:14:55 1985
Date-Received: Sat, 7-Dec-85 02:36:39 EST
Distribution: na
Organization: Georgia Institute of Technology
Lines: 22
Keywords: Real system software

> [..misc ravings about opposing views...]

One school of thought on intertask protection is that it should be
provided by the compiler.  An MMU checks EVERY access of memory,
whether the check is needed or not.  If you assume that assembler language
is dead (which is a popular, modern view) then the compiler can generate
code to check memory references where appropriate.  For example, a reference 

        A[5] := 123

can be checked at COMPILE time, and not at each execution, but

        A[I] := 123

cannot be checked at compile time, and must be checked at run time.

If your CPU has an adequate cache with a decent prefetch algorithm, the
execution of the checking instructions should not prove to take an excessive
amount of time.

All of this means that we simply need adequate compilers for the Amiga.