Hi Mark, The AHI options seem clearer for the junior programmers.
I've been using LA Rx,1(Rx) and BCTR Rx,0 since forever but in my newer code I'll use baseless and AHI for cleaner code that my junior partners can understand. There's nothing worse than having to find a PoP manual for that old junk you wrote back in the dark ages. Regards, Dougie On Thu, 10 Jul 2025 at 17:39, Mark Hammack < [email protected]> wrote: > Is there any advantage to using: > > LA Rx,1(,Rx) vs. > AHI Rx,1 > > Back in the old days (I started on S/370 with MVS right before XA came > out), to increment a register, you had to use option 1. Now, either will > work. I prefer the latter because I think it is clearer what you intend > but since it sets the CC flags, I'm not sure it is any "better" and may be > (slightly) slower. > > Really, the same question can be asked about: > > BCTR Rx,0 vs. > AHI Rx,-1 > > and > > LA Rx,value > LHI Rx,value > > Same thing, the latter is much clearer, especially for new-to-assembler > programmers. In the LA vs LHI case, LA is limited to 4095 whereas LHI can > go to 32767 so there is an advantage in some situations. > > IDK, maybe it's the closet C programmer in me... > > > > > *Mark Hammack* > -- DL1 @ Mastodon (https://mas.to/@dl1) <https://mas.to/@dl1>
