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From: henry@utzoo.UUCP (Henry Spencer)
Newsgroups: net.micro.68k,net.micro.16k
Subject: Re: Re: PDP11s vs the micros
Message-ID: <5874@utzoo.UUCP>
Date: Wed, 14-Aug-85 13:07:57 EDT
Article-I.D.: utzoo.5874
Posted: Wed Aug 14 13:07:57 1985
Date-Received: Wed, 14-Aug-85 13:07:57 EDT
References: <1617@hao.UUCP> <847@mako.UUCP> <2422@sun.uucp>, <2607@sun.uucp>
Organization: U of Toronto Zoology
Lines: 16

> > Any particular reason to do this rather than restart the instruction from
> > where it left off?
> 
> Less internal state to dump?  (Which means less microcode/whatever to do the
> dumping and restoring, and less code in the kernel to check that the state,
> if accessible to the user, hasn't been tampered with.)

Motorola obviously :-) views its 68020 line primarily as a way to sell
memory chips.  Between the incredible pile of trash it heaves onto the
stack when you take a page fault, and the huge internal state of the
68881 FPU that has to be shoveled in and out every time you context-switch
(what's the betting Motorola's next FPU chip has DMA? :-), the memory
market is clearly what they're aiming at.  That and the cache market.
-- 
				Henry Spencer @ U of Toronto Zoology
				{allegra,ihnp4,linus,decvax}!utzoo!henry