Well, depending on his exact logic, quite possibly yes. Charles
-----Original Message----- From: IBM Mainframe Assembler List [mailto:[email protected]] On Behalf Of Robin Vowels Sent: Friday, October 27, 2017 6:26 PM To: [email protected] Subject: Re: Using the High Halfs of registers From: "Tony Harminc" <[email protected]> Sent: Saturday, October 28, 2017 11:13 AM > On 27 October 2017 at 19:31, Wendell Lovewell > <[email protected]> > wrote: > >> ... >> Sorry for all the background. What I'm looking for are "high-half" >> versions of LA and BCTR commands, so that the incrementing and >> decrementing could be done with 2 statements per CSECT--without >> affecting the low halves of the register. For example in 31-bit land >> if R2 was always available, I could say "LA R2,1(R2)" at the start >> of the modules, and "BCTR R2,0" at the end. In this case reg 2 >> would always be the stack level. >> > > Add Immediate High (AIH). But when was it introduced...? There are no > change bars in the -10 edition of the PofO, so before then. Wouldn't it be necessary to clear the high half first?
