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From: mslater@cup.portal.com (Michael Z Slater)
Newsgroups: comp.sys.intel,comp.misc
Subject: Re: RISC/CISC Dual Processor
Message-ID: <24752@cup.portal.com>
Date: 6 Dec 89 16:45:22 GMT
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Organization: The Portal System (TM)
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>I have recently been reading some articles and advertisements for a dual
>processor system including both an Intel 80486 and an Intel 80860. Olivetti
>has manufactured such a system and is using the i860 as a co-processor of
>some sort on the motherboard - not an add-on board. Both processors have
>their own cache and share the main memory. It seems the i860 is controlled
>by (and held back by) the 25MHz limit of the 80486.
>
>What I can not figure out is how the i860 is used in a configuration like
>this. Is it used as a special purpose processor with a library of routines
>that it can execute?

For the moment, the short answer to how the i860 is used is "not at all".

Eventually, there will be application programs that support the i860 in this
configuration. Intel has a standard software loader and execution environment
for the i860, which provides the same application environment whether the
i860 is on an add-in card (e.g., Wizard) or on the system board.

I expect that, for the most part, program ported to the i860 will run
mostly, if not entirely, on the 860, and that it will be used  more as an 
"alternative processor" that as a "coprocessor".  I suppose there's on reason
why the main program loop couldn't remain on the 486, with certain subroutines
offloaded to the 860.

Michael Slater, Microprocessor Report    mslater@cup.portal.com