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From: dave@uwvax.UUCP (Dave Cohrs)
Newsgroups: net.unix
Subject: Re: RE: UNIX on uVAXen
Message-ID: <320@uwvax.UUCP>
Date: Fri, 20-Sep-85 09:24:37 EDT
Article-I.D.: uwvax.320
Posted: Fri Sep 20 09:24:37 1985
Date-Received: Sun, 22-Sep-85 06:11:07 EDT
References: <1619@brl-tgr.ARPA> <1639@umcp-cs.UUCP>
Organization: U of Wisconsin CS Dept
Lines: 25

> Another problem is that some of the string instructions on the
> uVax-II are ``minicoded'':  the arguments are put in the appropriate
> registers, then the CPU traps somewhere to let an assembly code
> routine handle the work.  Examples are scanc and matchc, but, I
> have been told, *not* movc3.

movc3 and movc5 are both 'real' instructions on the uvax-I, so I assume
they are also real on the uvax-II.  The silly COBOL instructions are
all simulated in software.  I've looked at the code -- they are long
and rather complex (I think that DEC was trying for efficiency).  The
emulated instructions on the uvax-I are:

ashp, cvtlp, cvtps, crc, addp4, subp4, cvtpt, subp6, milp, cvttp, divp,
cmpc3, scanc, spanc, cmpc5, movtc, movtuc, movp, cmpp3, cvtpl, cmpp4,
editpc, matchc, locc, skpc.

Of course, using these instructions should still be faster in general
usage that a C routine doing the same thing because the assembly code
*should* be well optimised.

-- 
Dave Cohrs
(608) 262-1204
...!{harvard,ihnp4,seismo,topaz}!uwvax!dave
dave@wisc-romano.arpa


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