FWIW, If the "branch technique" is faster, and depending on how high a percentage "most of the time" (as in "most of the time CURRENT will be zero") is, then the branch technique given as the alternative to no-branch is likely not optimal. Even with branch prediction technology, it is still better to have the "expected path" not take a branch.
So, for example (when LT is available), LT Rx,CURRENT JNZ Need_To_Add Return_From_Need_To_Add DS 0H ... Need_To_Add DS 0H A Rx,SUM ST Rx,SUM J Return_From_Need_To_Add Then you get to factor in how much "readability" is worth to you. Peter Relson z/OS Core Technology Design ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN