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ASSEMBLER-L - Makro für DIAG-Befehl (und Diskussion dazu)

Subject:

Re: macros to implement opcodes

From:

Bernd Oppolzer <bernd.oppolzer@T-ONLINE.DE>

Reply-To:

IBM Mainframe Assembler List <ASSEMBLER-LIST@LISTSERV.UGA.EDU>

Date:

2013.12.21 14:33:44


This will not work, because you have to consider the case where there is no
label coded on the calling instruction, then the ORG &LABEL is failing, because
it is a ORG without operand.

Kind regards

Bernd



Am 21.12.2013 13:51, schrieb J.G.:
> EJ's macro can of course be written in the form
>
>           MACRO ,
>   &LABEL  DIAG  &R1,&R2,&I1
>   &LABEL  LA    &R1,&I1.(&R2.,0)    Diagnose
>           ORG   &LABEL
>           DC    X'83'
>           ORG  ,
>           MEXIT  ,
>           MEND  ,
>
> and this form, which delegates the location-counter arithmetic to the
> assembler, seems to me to be at once clearer and less error-prone.
>
> Dijkstra's epigoni have conditioned many people to avoid the use of
> labels whenever possible, even at the expense of real ugliness, not
> present here; but the use of an already present label in this way
> seems to me to be entirely benign.   Moreover, their judicious use
> often makes it possible to avoid what T.H. has just called
> "fancier ORGs".
>
> J.G.
>

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