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From: A01MES1@NIU.BITNET (Michael Stack)
Newsgroups: comp.lang.asm370
Subject: Re:  Need string handling macros
Message-ID: <9011081730.AA21056@ucbvax.Berkeley.EDU>
Date: 8 Nov 90 17:24:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: IBM 370 Assembly Programming Discussion List
              <ASM370@OHSTVMA.BITNET>
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> If you're coding in 370 Assembler, then simply use the equivalent
> machine instructions.  SUBSTR ends up being either an EX (Execute) of
> an MVC (Move) instruction for "short" strings ...

Better, use MVCK.  The length is expected to be in a register so you
don't need to EXecute, and it is a true length so you don't need to
worry about decrementing by one (and it can be zero if that's useful).

The only drawback is that it requires an R3 operand containing the
storage key of the source location.  See POO for an example.

Michael Stack
Northern Illinois University
Bitnet:   A01MES1@NIU