Given that jumps are no longer than the equivalent branches, that's hard to argue with. LAY and LHI are other ones that I would expect to see used a lot, possibly more than LARL.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 עַם יִשְׂרָאֵל חַי ________________________________________ From: IBM Mainframe Assembler List <ASSEMBLER-LIST@LISTSERV.UGA.EDU> on behalf of Ed Jaffe <edja...@phoenixsoftware.com> Sent: Thursday, November 9, 2023 11:27 AM To: ASSEMBLER-LIST@LISTSERV.UGA.EDU Subject: Re: Internal Exit Routine Handling On 11/9/2023 4:06 AM, Seymour J Metz wrote: > The relative instructions are invaluable for large csects, but in this case I > believe that they are overkill. All he needs is the judicious placement of > DROP. > > OTOH, they are definitely instructions worth his time to learn. In addition to extending the practical size of a code segment and potentially making additional general-purpose registers available, relative branches are also better understood/optimized by the branch-prediction circuitry in the hardware since there is no question what the final branch target address will be. Furthermore, relative branches avoid the AGI suffered by based branches that occurs every time a code base register is loaded (or re-loaded). IMHO, relative branch use is a "best practice" in all situations. I *never* use a based branch if an equivalent relative branch will suffice... -- Phoenix Software International Edward E. Jaffe 831 Parkview Drive North El Segundo, CA 90245 https://secure-web.cisco.com/1EL3QVedrIpZxwM7sZ-eG4OTKZrFwZSVKNvDOpv0LAnPdIeYl0eiWPKhHkTf4Wa-E_U9tiD6Pp6YPt5FhK6Y-5MGD_0ePM4kCT1CHMFsINcD__zwf_7y0Mmw16F-gmHQt_HnbDUNt2d6DwG-nzK7U7X_6WrBQsI6MLDviLk6mH9higY_fcqB71b6d0r7uB4_JEFMuHsDl3II3oJPIXN43sl-7ZqGoNNLNd_9l3J4-RteKw1lmsdNavSGR4ZpXa918K4Y6WUaiA4_B9S_GsO8yvgNVXOiGvE7H1Ct2knUVuPD5qslEyOjWZhYY6ZqLYknkVxa0hReXwXPnM8CkPr8ytMsMkThJwO3pWt_feiB4HSmTPK1RhSDkk1XpFfn-UZ1TRrjk6XZNdSgwPoNHliTzrNXtV2Ag-W7z35ngoZoOgzs/https%3A%2F%2Fwww.phoenixsoftware.com%2F -------------------------------------------------------------------------------- This e-mail message, including any attachments, appended messages and the information contained therein, is for the sole use of the intended recipient(s). If you are not an intended recipient or have otherwise received this email message in error, any use, dissemination, distribution, review, storage or copying of this e-mail message and the information contained therein is strictly prohibited. If you are not an intended recipient, please contact the sender by reply e-mail and destroy all copies of this email message and do not otherwise utilize or retain this email message or any or all of the information contained therein. Although this email message and any attachments or appended messages are believed to be free of any virus or other defect that might affect any computer system into which it is received and opened, it is the responsibility of the recipient to ensure that it is virus free and no responsibility is accepted by the sender for any loss or damage arising in any way from its opening or use.
