Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!usc!rpi!eliot
From: eliot@aix01.aix.rpi.edu (Brian Eliot)
Newsgroups: comp.lang.asm370
Subject: Re: New System/3x0 Instruction
Keywords: MVS, ESA, instructions, assists, microcode
Message-ID: <$2_=MK#@rpi.edu>
Date: 17 Mar 91 18:26:58 GMT
References: <9103171023.AA28323@ucbvax.Berkeley.EDU> <9103171404.AA01042@ucbvax.Berkeley.EDU>
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Organization: Rensselaer Polytechnic Institute, Troy NY
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> Neil Rickert <rickert@CS.NIU.EDU> said:
>
>>Really?  Ever heard of the MVS assists "OBTAIN LOCAL LOCK", "ADD FRR",
>>etc.?
>
> Sure they are.  But they are not considered System/3x0 instructions, and
>are not documented in Principles of Operation.  Rather they are considered
>part of a microcode assist for MVS.

I don't pretend to know what is considered to be a System/3x0 instruction
given that the descriptions are scattered among so many manuals besides
the Principles of Operation.  But the MVS assists are described in

  GA22-7079   System/370 Assists for MVS
  SA22-7092   Assists for MVS/XA

A bigger concern is the new architectural category added by ESA/390
oxymoronically defined as "architected but not described".  Expanded
storage and Move Page, which pre-date ESA/390, already fall into that
category.  ESA/390 adds to it things like ETR (Sysplex) and ICF
(Cryptographic Facility) which in practical terms means such things
will be confined to use by MVS alone.

Brian Eliot
Information Technology Services
Rensselaer Polytechnic Institute