On 27 October 2017 at 20:12, Charles Mills <[email protected]> wrote: > Unfortunately, a lot of the high half instructions come along (not > surprisingly) with the "high-word facility" which is z196 and above. I've > never used it, but Add Immediate High (AIH) looks like what you are looking > for -- but it's high-word facility.
Great minds, etc. > How about the floating point registers? Could you use one of them to hold > your depth code? I don't know the FP instruction set at all. I see a > number of storage to register adds. > Or if you aren't otherwise using them, put a 1 in an FPR on entry, and then use the RR instructions to add and subtract it. But of course unless you just want to be sure your counter is zero at appropriate times, you'll need to convert to integer. That's not hard, but then how much unfamiliar stuff would you be introducing for the next programmer? There's always old-style packed decimal. Storage to storage. Probably not as slow as one might expect, but certainly worse than RR or RI type instructions. Tony H.
