On 17 February 2014 09:37, John McKown <john.archie.mck...@gmail.com> wrote: > LT R0,CURRENT #LOAD CURRENT AND SET CC > SPM R1 #SAVE CC FROM LT > A R0,SUM #ADD SUM TO IT > IPM R1 #RESTORE CC FROM LT > STOC R0,SUM,NZ #STORE SUM ONLY IF CC OF LT WAS NZ > > Basically this loads CURRENT into R0, setting the CC based on its value. > Then saves the CC in R1. Adds the SUM value into R0. Restores the CC from > the LT, because the Add destroyed it. Then only stores the result in SUM if > the CC is "Not Zero", as set by the LT.
Not that it affects your proposal, but I think your SPM and IPM are reversed there... It's perhaps interesting that IPM appeared only in 370/XA; on 24-bit systems BALR was expected to do. Tony H. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
