Maybe a little less of a kludge using SETA arithmetic function SLL, but maybe
not:
LCLA &IIHFARG
&IIHFARG SETA SLL(X'01', 16)+X'2345'
IIHF R00,&IIHFARG
Being able to code the SETA argument in the instruction would be nicer:
IIHF R00, SLL(X'01', 16)+X'2345'
Have not tried either of those in an actual assembly yet, just guessing here.
Peter
-----Original Message-----
From: IBM Mainframe Assembler List [mailto:[email protected]] On
Behalf Of Ngan, Robert
Sent: Monday, February 27, 2017 5:45 PM
To: [email protected]
Subject: Re: HLASM anomaly
The ability to specify:
IIHF R00,H'12345,0'
to insert 12345 into bytes 0-1, and zero into bytes 2-3 of register would be
useful.
Kludge for this is:
IIHF R00,12345*65536
which is ugly, while:
IIHL R00, 809041920
is even uglier!
Robert Ngan
-----Original Message-----
From: IBM Mainframe Assembler List [mailto:[email protected]] On
Behalf Of Steve Smith
Sent: Saturday, February 25, 2017 11:24
To: [email protected]
Subject: Re: HLASM anomaly
Exactly. HLASM is inconsistent in conflating storage types (F, H, etc.) and
data types (B, X, C), which definitely adds to the confusion. C (and its
derivatives) makes more sense in this regard. OTOH, C does have the
interesting feature that the size of ints (and shorts and
longs) and pointers can vary. PL/I might have the best model, but I haven't
done any serious work with it in many years.
sas
On 2/25/2017 11:42, Charles Mills wrote:
> Another way of looking at things is that X' serves two different roles in the
> assembler syntax. I became aware of this when I moved from a long career
> writing assembler to C++ as my primary language.
>
> X' signifies (a.) that the constant that follows is in hexadecimal notation
> and (b.) a unit of storage, a byte.
>
> Thus you can say LHI 0,X'23' (role a.) or DC X'23' (roles a. and b.).
> Consider the contrast with H' which is only a unit of storage. You can say DC
> H'23' but you would not expect to be able to code LHI 0,H'23'. So, similarly,
> you can code DC 2X'23' but not LHI 0,2X'23'
>
> FWIW and OT, C/C++ separates the two functions. 0x23 represents only the
> quantity 23 base 16, not a unit of storage. You can say foo = 0x23 (roughly
> analogous to LHI) but if you want to define storage, you must explicitly
> state the unit of storage that you are defining: char foo = 0x23 or short foo
> = 0x23 (roughly equivalent to FOO DC X'23' and FOO DC H'35' respectively).
>
> Charles
>
>
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