Path: utzoo!attcan!uunet!cbmvax!daveh
From: daveh@cbmvax.UUCP (Dave Haynie)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Unsupported Programming Practices
Message-ID: <5608@cbmvax.UUCP>
Date: 3 Jan 89 16:46:49 GMT
References: <5605@cbmvax.UUCP>
Organization: Commodore Technology, West Chester, PA
Lines: 35

in article <5605@cbmvax.UUCP>, carolyn@cbmvax.UUCP (Carolyn Scheppner CATS) says:
> Keywords: warning unsupported

>                               IMPORTANT !    

>      Do not use assembler instructions which are priviledged on any 
> 68000 family processor.  All addresses must be 32 bits.  Do not use
> the upper 8 bits for other data.  Do not execute code on your stack or
> put system structures on your stack.  Do not use the TAS instruction.
> Do not use software instruction based timimg loops or delays.

Along similar lines:

	Don't write self-modifying code.  It currently CAN'T be supported
	for future systems.  Even if you get clever and manage to always
	overrun the cache on a 68020 system, you'll probably not overrun
	the cache on a future system.

	If you're messing with exception stacks, you're responsible for
	doing the right things for each 680x0 processor.  Note that even
	the 68010 has it's own special exception stack in some cases.

	Don't expect OS level things done by user level programs to always
	work.  Things like changing cache parameters or MMU banging are by
	definition things that should be managed by the operating system.
	Currently, some of these aren't.  In the future, they should be.  And
	programs that muck with them today will not likely work once OS 
	support is provided.

>   Carolyn Scheppner -- CATS  Commodore Amiga Technical Support
>   PHONE 215-431-9180   UUCP  ...{uunet,allegra,rutgers}!cbmvax!carolyn 
-- 
Dave Haynie  "The 32 Bit Guy"     Commodore-Amiga  "The Crew That Never Rests"
   {uunet|pyramid|rutgers}!cbmvax!daveh      PLINK: D-DAVE H     BIX: hazy
              Amiga -- It's not just a job, it's an obsession