All the instructions mentioned below have their lengths determined at
compile
time. String instructions (and strings in the sense of this thread) are
strings
with lengths varying at run time. This can be done on the mainframe
using EX
or MVCL, CLCL etc ... but not with the instructions mentioned below.
In my post, I really meant instructions to support null-terminated strings
at a hardware level, which were introduced into z-Arch a long time AFTER the
first commercially available C compiler (C/370) was introduced by IBM and
widely used by customers. I worked with C/370 on the mainframe starting
in the early 1990s, and the string instructions in z/Arch came about 10
years
later, IIRC. I may be wrong with the years, but the 10 years delay
should be
correct ...
Kind regards
Bernd
Am 08.02.2018 um 21:14 schrieb Seymour J Metz:
WTF? How are CLC, MVC, TR and TRT not string instructions? Or do you only
consider it to be a string if it conforms to the abominable C use of 0 as a
string delimiter?
--
Shmuel (Seymour J.) Metz
http://mason.gmu.edu/~smetz3
________________________________________
From: IBM Mainframe Assembler List <[email protected]> on behalf of
Paul Raulerson <[email protected]>
Sent: Monday, February 5, 2018 10:53 PM
To: [email protected]
Subject: Re: Fair comparison C vs HLASM
On Feb 5, 2018, at 7:29 PM, Robin Vowels <[email protected]> wrote:
From: "Bernd Oppolzer" <[email protected]>
Sent: Tuesday, February 06, 2018 1:23 AM
Am 05.02.2018 um 14:42 schrieb Gord Tomlin:
And, BTW, the historic facts are simply wrong:
IBM had a C compiler for MVS (and VM, I believe) long before there were
string instructions on z/Arch.
MVC, CLC, MVCL, CLCL, MVO, MVN, ED, EDMK, TR, TRT
are all string instructions. Most of these were available in 1965 with the
S/360. Long before C.
Oh my - but no. These are >character< operators, not string operators. Much
more akin to C’s memcpy() than anything else. (Yes, memcpy() was built, in part, to
emulate them.)
CLST, CUSE, MVST, SRTST, and the later generations of these and other
instructions work on strings. Albeit, I think the definition of “string” in
this case is a little dodgy.
I must say, it is a lot of fun to read some of these postings. I don’t
necessarily agree with a lot of them, but they are fun to read.
z/OS as the epitome of a portable OS? HLASM more portable that C? Does anyone
really buy into that? I assumed it was a just leg pulling… :)
-Paul
