On 2020-06-02, at 14:01:28, MELVYN MALTZ wrote:
>
> Labels...
> Even back in the 60's I was taught never to put a label on an instruction
> I only break that rule now for the subject of an EX (and its variants)
>
It's safer than
label EQU *
> Returning CC from a subroutine...
> Have to point out that IBM do this in the VSAM TESTCB macro
>
I had one co-worker who insisted on doing that. He augmented
our MVS/XA common return macro to:
IPM
...
SH R13,=Y(workarea_length)
...
SPM , restore CC
then *I* was tasked with porting to VM/370. No IPM. I did:
LH R1,=Y(-workarea_length)
LA R13,0(R1,R13)
I had a tough time in code review. Reviewers called me
naive for using a negative value in a base register. No,
the were ignorant; the code worked and was correct.
-- gil
