On 2017-04-05, at 09:49, somitcw wrote:

> I use IFOX00.  Okay, you can laugh now.
>  
Why?  Money?  But why not IEV90?  (We long deferred conversion
to ASMA90 because we were stuck with a SYSPRINT postprocessor.)

Where did you find it?

> Since IFOX00 doesn't support any RXE or RXY instructions,
> someone wrote a MACRO to use an RX instruction to generate RXE and RXY 
> instructions.
> It just codes an RX instruction like LA, STC, or IC and then overlays the 
> opcode and adds two bytes to the end.
> Displacement-high is not supported so is always zero.
> 
> The question is on the ORG use.
> 
> The code does:
>   ORG *-4
>   DC   XL1'E3'  Overlay the opcode
>   ORG *+3
> 
> My question is the second ORG.
> Should it instead be ORG , ?
> Which is safer?
> Could a later errant "ORG ,' mess thing up royally?
>  
Actually, a prior ORG presents the greater hazard.

> Am I needlessly worrying?
> 
No.

> Note: IFOX00 was before LOCTR instruction existed.
>  
I think IEV90 has LOCTR.  With determination, you could implement
the entire z instruction set as macros.

-- gil

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