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From: peter@graffiti.UUCP (Peter da Silva)
Newsgroups: net.arch
Subject: Re: 386 info
Message-ID: <414@graffiti.UUCP>
Date: Wed, 6-Nov-85 12:21:58 EST
Article-I.D.: graffiti.414
Posted: Wed Nov  6 12:21:58 1985
Date-Received: Sat, 9-Nov-85 06:44:52 EST
References: <965@mcnc.mcnc.UUCP> <2359@ukma.UUCP>
Distribution: net
Organization: The Power Elite, Houston, TX
Lines: 16

> also possible to use just about any register as an index register.  (I
> think SP is the only register that can't be used this way - it remains
> almost exclusively as a stack pointer.)  So it should be a lot easier
> to write an optimizing compiler - the only thing is that to use use
> these additional addressing options usually lengthens the instruction
> by an extra byte.

Yes, but indexing off the stack pointer is something compilers like to do:
it's a very convenient way of accessing local storage. If you can't
index off the SP you have to waste a general purpose register as a base
register for these local variables...
-- 
Name: Peter da Silva
Graphic: `-_-'
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