UNIX on uVAXen
Dave Cohrs
dave at uwvax.UUCP
Fri Sep 20 23:24:37 AEST 1985
> 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 at wisc-romano.arpa
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