Martin,

As I understand LARL, the current PSW is used as the base to address the 
symbol.  If the symbol is in a DSECT, the LARL instruction should generate an 
assembler error.

John

-----Original Message-----
From: IBM Mainframe Assembler List [mailto:[email protected]] On 
Behalf Of Steve Comstock
Sent: Monday, December 20, 2010 9:25 AM
To: [email protected]
Subject: Re: Baseless vs Based

On 12/20/2010 7:05 AM, Bodoh John Robert wrote:
> Ed, Martin, John, Tony, et al,
>
> What I am doing is creating macros that are used by any other
> application.  I was hoping to avoid having the user of these
> macros have to specify the technique needed to address symbols.

> That sounds clutzy and it nowhere else in the assembler do I
> have to tell the assembler that kind of detail.
>
> At the time the macro is being used, the macro does not know
> whether baseless coding is being used or not and whether or not
> a symbol is within the current CSECT or not.  If the symbol is
> within the current CSECT and code invoking the macro is using
> baseless coding, the macro MUST use baseless instructions.


> AsI understand it, the symbol is within the current CSECT,
> baseless instructions can be used whether or not the invoking
> code is using baseless or not.  Otherwise, based instructions
> MUST be used.

I'm at a loss here. First, you reference symbols for one
of two reasons: 1) a target for a branch or execute instruction,
and 2) a location for an operand.

In case 1), you can always use the so-called baseless instructions;
in case 2), it depends on the operation you need to perform.

For example, loading an address of a location can always be done
by LARL - unless the item is at an odd address! If you need to
work with packed decimal data, you must use the xP instructions,
all of which require base / displacement.

What instructions are you thinking of where you would choose
between baseless and based?

>
> I am surprised this not considered a hole in the assembler
> and is not more pervasive than just for me and my simple case.
> Do not other macros have the same problem?
>
> John
>
> -----Original Message-----
> From: IBM Mainframe Assembler List [mailto:[email protected]] 
> On Behalf Of Martin Trübner
> Sent: Saturday, December 18, 2010 3:55 AM
> To: [email protected]
> Subject: Re: Baseless vs Based
>
> Ed,
>
> While I understand your point (missed you anyway in this thread ;-) ) I
> do not see the word DSECT mentioned in the OP-s stmt.
>
> John, was your question as simple as I assume or was it as
> sophisticated as Tony and Ed answered (with solutions from John E. and
> Paul)?
>
> --
> Martin
>
> Pi_cap_CPU - all you ever need around MWLC/SCRT/CMT in z/VSE
> more at http://www.picapcpu.de
>


--

Kind regards,

-Steve Comstock
The Trainer's Friend, Inc.

303-393-8716
http://www.trainersfriend.com

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