Newsgroups: comp.arch
Path: utzoo!utgpu!watserv1!watdragon!rose!ccplumb
From: ccplumb@rose.uwaterloo.ca (Colin Plumb)
Subject: Re: Vector processors, i860
Message-ID: <1991Feb3.061217.21988@watdragon.waterloo.edu>
Keywords: Vector, array processors, i860.
Sender: daemon@watdragon.waterloo.edu (Owner of Many System Processes)
Organization: University of Waterloo
References: <798@nvuxl.UUCP>
Date: Sun, 3 Feb 91 06:12:17 GMT
Lines: 16

hsong@nvuxl.UUCP (g hugh song) wrote:
> Why is it so hard to build a UNIX machine with Intel's i860 chip?  What is
> missing in this chip for building a UNIX machine out of this chip?

Return from interrupt.  When the chip takes an exception, it sort of
drops all the bits in the pipleine on the floor and lets software
put the pieces back together.  The code to restart from an interrupt
is, I'm told, 10,000 lines of assembler.  And you still have to
avoid one or two code sequences.

It's a great hot box, but for taking interrupts, it's a pig.

(It's also, as Henry points out, a pain in the ass to program... nobody
has a compiler which can come close to hand coding yet.)
-- 
	-Colin
