I don't know why he uses the term indirect; if anything, they're more direct then the old branches. I wouldn't expect them to be more efficient, but if you use them for all branches then you can save a register, which can avoid otherwise extraneous saves and restores. Unless I have to run on a really old box, I'd use the jump instructions all the time.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Assembler List [ASSEMBLER-LIST@LISTSERV.UGA.EDU] on behalf of Schmitt, Michael [michael.schm...@dxc.com] Sent: Friday, March 4, 2022 1:33 PM To: ASSEMBLER-LIST@LISTSERV.UGA.EDU Subject: Jump vs. Branch Am I correct in assuming that branch relative (HLASM "jump") instructions are more efficient than branches using register+displacement? C. Kevin Shum's IBM Z System Processor Optimization Primer says: Use relative branches instead of non-relative (indirect branches) when possible but "indirect" is what throws me. The only indirect branch I'm aware of is Branch Indirect on Condition (BIC).
