Once upon a time, if you wanted to put a label on a separate line you used
DS 0H not EQU * because 1) you got 1/2 wd alignment needed for code and
not possible S0C1s and 2) DS 0H worked with TSO TEST and EQU * did not

> From: glen herrmannsfeldt <[email protected]>

> Someone wrote:

> > MYCSECT  CSECT
> >          USING *,R15
> >          B     BYID
> > ID       DC    C'module-name'
> > BASES    DC    A(MYCSECT)
> >          DC    A(MYCSECT+4096)
> >          DC    A(MYCSECT+2*4096)
> >          DC    A(MYCSECT+3*4096)
> > BYID     DS    0H
> >          LM    R9,R12,BASES
> >          DROP R15
> >          USING MYCSECT,R9,R10,R11,R12

> This looks more like compiler generated code than what I
> would expect from a person. Then again, my start on learning
> assembler was reading the LIST output from the compilers.

> When I saw the 4095 in the subject, I was expecting the old:

>         L 12,4095(15)
>         L 11,4095(12)
>         L 10,4095(11)
>         USING MYCSECT,15
>         USING MYCSECT+4095,12
>         USING MYCSECT+2*4095,11
>         USING MYCSECT+3*4095,10

> The LM form seems to waste fewer bytes loading the base registers
> (including the A constants), especially if one already has the
> branch around the csect name.

> But, why the DS 0H instead of putting the label on the LM?

> -- glen


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