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From: pop@mtu.UUCP (Dave Poplawski)
Newsgroups: net.arch
Subject: Re: The little assembler that lies...
Message-ID: <194@mtu.UUCP>
Date: Sat, 1-Jun-85 09:04:47 EDT
Article-I.D.: mtu.194
Posted: Sat Jun  1 09:04:47 1985
Date-Received: Thu, 6-Jun-85 10:20:12 EDT
References: <893@sdcsvax.UUCP>
Reply-To: pop@mtu.UUCP (Dave Poplawski)
Organization: Michigan Tech, Houghton, MI
Lines: 13


The reason the assembler gives the sequence instead of the  single  RESTORE
instruction  is because of a chip bug.  I don't remember the exact problem,
but as I recall,  if  a  page  fault  happened  when  the  instruction  was
executing  a  timing problem in the chip would cause the WRONG registers to
be restored.  It was easier (schedule-wise) to fix the  assembler  than  to
fix  the chip.  Hopefully this will be fixed in future versions of the chip
- it should help performance a bit.
-- 
Dave Poplawski
Michigan Technological University
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