René, thanks much, I'm aware of those, and no, they don't answer my question.
And no slam on you intended of course. Thank you for your answer. The shortcomings of the doc are of course not your fault! The first link I am well aware of. They don't tell one how to write satisfactory code. "GRP8-15 => preserved" -- Preserved by who? Does that mean "the programmer must preserver them" or "they will be preserved for you"? What does is say about my obligations when writing code? And the examples are not what I am looking for at all. They are examples of what the interfaces must be if you are writing a new LE-conforming compiler. "These are examples, not definitive code sequences that must be generated by conforming compilers." They are of no help in writing basic everyday code that runs under the existing interface. Really, thanks. Charles -----Original Message----- From: IBM Mainframe Assembler List <[email protected]> On Behalf Of Rene BRANDT Sent: Monday, April 21, 2025 1:48 PM To: [email protected] Subject: Re: XPLINK register conventions for called HLASM? Hi Charles, Is that of interest for you ? https://www.ibm.com/docs/en/zos/3.1.0?topic=conventions-extra-performance-linkage-xplink-call-linkage and examples : https://www.ibm.com/docs/en/zos/3.1.0?topic=SSLTBW_3.1.0/com.ibm.zos.v3r1.ceev100/cee1v269.html HTH René Le lundi 21 avril 2025 à 20:43:22 UTC+2, Charles Mills <[email protected]> a écrit : Jonathon, yes there is a lot in the LE PG. But it's not really what you would want if you were writing a program. Yes, the stack frame layout is documented. But how do I define variables in the DSA? How do I address it? Yes, the register "conventions" are "documented." What does "preserved" mean? Does that mean that I am supposed to preserve it? I think it is classic documentation in that if you already know the answers, then yup, sure enough, you can prove that the answer is right there on page 487. But if you are trying to learn to use it for the first time then -- at least in my reading -- it is a jumble of random facts. Or perhaps I asked the wrong question. Let me rephrase my question: Can you recommend a tutorial on writing a C++ XPLINK subroutine in HLASM? (And if not, then how DOES IBM expect customers to do so?) Charles -----Original Message----- From: IBM Mainframe Assembler List <[email protected]> On Behalf Of Jonathan Scott Sent: Monday, April 21, 2025 9:49 AM To: [email protected] Subject: Re: XPLINK register conventions for called HLASM? You said "a little bit" in the LE PG. From a quick glance, I'd say there is "a lot" in the LE PG and that most of your questions are answered by what is in there, especially in subtopics (stack frame, save area layout, register usage) so it's difficult to know what else to add. https://www.ibm.com/docs/en/zos/3.1.0?topic=environment-using-extra-performa nce-linkage-xplink Jonathan Scott -----Original Message----- From: IBM Mainframe Assembler List <[email protected]> On Behalf Of Charles Mills Sent: 21 April 2025 17:37 To: [email protected] Subject: Re: XPLINK register conventions for called HLASM? Really? No one knows this stuff? I don't feel so bad. Charles
