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From: tabu6@CCVAX.IASTATE.EDU (Adam Goldberg)
Newsgroups: comp.lang.asm370
Subject: New System/3x0 Instruction
Message-ID: <1991Mar18.011255.15806@news.iastate.edu>
Date: 18 Mar 91 01:12:55 GMT
Sender: news@news.iastate.edu (USENET News System)
Reply-To: tabu6@CCVAX.IASTATE.EDU
Organization: Iowa State University, Ames, IA.
Lines: 24

It seems that we're trying to say some opcodes, say LA is a machine
instruction, while other more complicated and implemented in microcode
instructions are not 'instructions'.  Where would you draw the line?  Clearly
L, LA, STH etc are instructions.  But what about MVC? MVCL? PACK? Then there is
at least one (don't have the opcode handy) instruction that used to be about a
4K block of MVS code that IBM (in their infinite wisdom) decided to implement
in microcode for speed.  Even if opcode WXYZ does about 10,000 different
things, if it's an opcode, it's an opcode--therefore a 3x0 instrucion.  On the
other hand, if it's a macro that makes a SVC (or equivalent), it's an operating
system function.  It seems that that is the line that has to be drawn.

And by the way, someone asked a little while back if anyone could provide a
list of SVC's and what they do.  My response would be that there are a number
of IBM-defined SVC's, and there are also installation-dependent SVCs that are
configured by the site--for example, RACF vs ACF/2...


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+ Adam Goldberg                         Bitnet:   tabu6@ISUVAX.BITNET        +
+ Iowa State University                 Internet: tabu6@CCVAX.IASTATE.EDU    +
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