On Mon, 17 Feb 2014 07:49:18 -0500, Peter Relson wrote: > >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), > (It's possible that CURRENT has just been calculated and CC is already set.)
> 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 > Is there a maxim here? When the programmer expects that a branch will usually be taken, is it better to avoid: BC C,USUALLY and code instad: BC 15-C,*+8 B USUALLY ??? >Then you get to factor in how much "readability" is worth to you. > Macros are your friend. But does providing "readability" at the programming interface level make such a macro unpleasantly verbose internally? -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN