I think there are many better uses of IBM development time.
-Original Message-
From: IBM Mainframe Assembler List [mailto:ASSEMBLER-LIST@LISTSERV.UGA.EDU] On
Behalf Of MELVYN MALTZ
Sent: Friday, June 11, 2021 4:36 PM
To: ASSEMBLER-LIST@LISTSERV.UGA.EDU
Subject: A problem with OPEN and
Forgive me for belaboring this but you have gotten me thinking.
If you can come up with an example of OPEN MF=E/L coding, no matter how
contrived and obscure, that will
- Let you store data into the MVS supervisor or an MVS control block
(despite your being KEY=8)
- Let you store data into some
OK, I kind of get your point. The OPEN will store the new R5 into the
executed MVC, which will cause it to move 256 bytes, regardless of the value
in R2.
But so what? I can write examples of assembler code all day that will work
very, very badly. (Sometimes I even do it unintentionally.) Your
I think one of the features (ha!) of assembler is your gun, your bullet,
your foot. A store instruction (ST) into a halfword will probably cause
storage corruption, with probably unhappy results. There might be a halfword
of slack after the halfword in some cases, and then some unrelated change
No.
On Fri, Jun 11, 2021 at 4:36 PM MELVYN MALTZ <
072265160664-dmarc-requ...@listserv.uga.edu> wrote:
> 1) An OPEN/CLOSE with MF=L,MODE=24 can be overlayed with an
> MF=E,MODE=31 (and vice-versa). This results in destruction of the
> list,
> abends would occur
>
> 2) An OPEN/CLOSE
1) An OPEN/CLOSE with MF=L,MODE=24 can be overlayed with an
MF=E,MODE=31 (and vice-versa). This results in destruction of the list,
abends would occur
2) An OPEN/CLOSE with MF=L with (say) 2 entries can be overlayed with an
MF=E with 3 entries. The end-of-list bit isn't touched, but
