Tom,
IIUC, what you're suggesting is this:
CLC &FIELD1(2),&FIELD2
and that works if &FIELD1 is a relocatable symbol. But &FIELD1 might be a
displacement and a base; e.g., 7(R3) , in which case this would be generated:
CLC 7(R3)(2),<etc>
Or &FIELD1 could be any other valid relocatable expression that would generate
invalid syntax if I simply append (2) to the end of the string. That's my
problem: the syntax of the explicit length insertion depends on the syntax of
the relocatable expression used for &FIELD1.
David
On Mon, 26 Feb 2024 10:21:37 -0500, Tom Marchant <[email protected]>
wrote:
>Perhaps I'm being dense, but why not
> CLC FIELD1(2),FIELD2
>
>--
>Tom Marchant
>
>On Mon, 26 Feb 2024 09:47:29 -0500, David Eisenberg
><[email protected]> wrote:
>
>>Well, it's a CLC (not an MVC)... but I understand your solution. With that
>>approach, and PRINT NOGEN is in effect, I get this in the listing:
>>
>> Loc Object Code Addr1 Addr2
>>0002AC D501 0000 0000 00000 00000
>>
>>and what I'm trying to do (if possible) is to show the relocatable addresses
>>under Addr1 and Addr2 in the listing alongside the D501. I.e., I'd like to
>>generate a single CLC instruction, so that it looks that way in the printed
>>object code. (I realize that PRINT NOGEN would show the addresses in the
>>expansion, but they still wouldn't appear on the same line as the CLC
>>opcode.) So far, the best solution I've come up with is my approach # 2 below
>>(a single DC statement) which produces:
>>
>> Loc Object Code Addr1 Addr2
>>0002AC D501BE65BE63
>>
>>That's not bad, but the assembler treats it like a DC (which it is), and not
>>a machine instruction... and it looks like a DC in the object code.
>>
>>The reason I'm generating the CLC in a macro is because the macro is doing
>>much more than this. There are various macro keyword parameters that I
>>haven't bothered showing here, and lots of analysis going on with the
>>comparands before I generate the CLC. I genuinely believe that showing all
>>those things here would only serve to complicate my question.
>>
>>David
>>
>>On Mon, 26 Feb 2024 13:44:17 +0000, Seymour J Metz <[email protected]> wrote:
>>
>>>Why? What are you trying to solve by wrappng the MVC in a macro?
>>>
>>> MVC 0(2),0
>>> ORG *-4
>>> DC S(&OP1)
>>> DC S(&OP2)
>>>
>>>but, again, why?
>>>
>>>--
>>>Shmuel (Seymour J.) Metz
>>>http://mason.gmu.edu/~smetz3
>>>עַם יִשְׂרָאֵל חַי
>>>נֵ֣צַח יִשְׂרָאֵ֔ל לֹ֥א יְשַׁקֵּ֖ר
>>>
>>>________________________________________
>>>From: IBM Mainframe Assembler List <[email protected]> on
>>>behalf of David Eisenberg <[email protected]>
>>>Sent: Monday, February 26, 2024 8:22 AM
>>>To: [email protected]
>>>Subject: Macro parameters: parsing a relocatable address
>>>
>>>I’m seeking some guidance if anyone is able to help. I’d like to write a
>>>macro like this:
>>>
>>>&NAME MYCLC &FIELD1,&FIELD2
>>>
>>>in which both &FIELD1 and &FIELD2 are relocatable addresses. It’s &FIELD1
>>>that is of particular interest to me. &FIELD1 might be expressed as a
>>>hard-coded displacement and base register, or a relocatable symbol… or it
>>>could be an absolute symbol equivalent to a displacement, followed by a base
>>>register… etc. I.e., it could be any valid relocatable address syntax. What
>>>&FIELD1 will *not* have is an *explicit length.* The macro parameters will
>>>specify valid relocatable addresses, and nothing more.
>>>
>>>My question: I’d like the MYCLC macro to generate a CLC instruction in which
>>>the two parameters are compared to each other for a constant length of 2. So
>>>far, the only ways I can think of to do this are:
>>>
>>>1. Parse &FIELD1 to figure out how the relocatable address is expressed, and
>>>insert an explicit length of 2 to generate a valid CLC first operand. I
>>>would do it that way, but (unless I'm missing something) it seems quite
>>>complex to code.
>>>2. Generate this DC statement: DC X’D501’,S(&FIELD1,&FIELD2) . This seems to
>>>work, but it’s a bit unattractive in a PRINT GEN (and it looks a bit odd in
>>>the assembly listing, because the assembler doesn't treat it like a machine
>>>instruction in the object code on the left side of the listing).
>>>
>>>I’m wondering if anyone can suggest a reasonable way to code option 1 above.
>>>Can the macro assembler give me any help in parsing &FIELD1 so that I can
>>>transform that parameter to insert an explicit length, regardless of how
>>>&FIELD1 is expressed? Or is there some other approach that I haven’t
>>>considered at all? Or should I just go with option 2 above?
>>>
>>>Please note that I don’t want the macro to generate more than one machine
>>>instruction. One way or another, I just want the macro to generate a CLC for
>>>a length of 2. (And I really do want the CLC located in the macro as opposed
>>>to open code, because the macro does some analysis on the comparands prior
>>>to generating the CLC.)
>>>
>>>Any advice would be appreciated... thank you!
>>>
>>>David
