Path: utzoo!attcan!uunet!garfield!john13
From: john13@garfield.MUN.EDU (John Russell)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Unsupported Programming Practices
Message-ID: <5065@garfield.MUN.EDU>
Date: 7 Jan 89 16:36:03 GMT
References: <5605@cbmvax.UUCP> <10227@well.UUCP> <5632@cbmvax.UUCP>
Reply-To: john13@garfield.UUCP (John Russell)
Organization: Memorial University of Newfoundland
Lines: 26

In article <5632@cbmvax.UUCP> steveb@cbmvax.UUCP (Steve Beats) writes:
]If Exec ever gets its act together and starts
]using the MMU, your stack would be private memory.  If graphics attempted to
]access the RastPort (as a separate task through Intuition for instance) it 
]would cause an illegal access exception.  I would suggest you either:-
]
]a)	Allocate rastports using MEMF_PUBLIC
]b)	Allocate a new stack using MEMF_PUBLIC

Is that to say that having a rastport as a global variable will also cause
choking, due to possible non-MEMF_PUBLICness of data hunks? In that case
could a FixHunk-type program be constructed to remedy the problem?

What would be nice would be a "validation" version of Exec. I'll bet that
with very little effort a Kickstart could be made which would require you
to follow some of these rules, and yell at you if you didn't. Eg, do a
typeofmem on memory that was being accessed, and complain if it should be
MEMF_PUBLIC but wasn't. This would be just for testing purposes, and wouldn't
require the actual presence of the MMU/68020/32-bit ram etc, but would detect
stuff which would break on them.

John
-- 
"If you steal all money, kids not be able to BUY TOYS!"
			-- Saturday morning cartoon character explaining
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