If I had to do it on an old machine before MVHHI then I'D use XC for clarity. I suspect that the XR/STH is the fastest of your three.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 עַם יִשְׂרָאֵל חַי נֵ֣צַח יִשְׂרָאֵ֔ל לֹ֥א יְשַׁקֵּ֖ר ________________________________________ From: IBM Mainframe Assembler List <[email protected]> on behalf of David Clark <[email protected]> Sent: Monday, February 9, 2026 1:48 PM To: [email protected] <[email protected]> Subject: Half-word Counter in Storage -- Best Practice External Message: Use Caution If a half-word counter has to be in storage (to save on registers) and must start at zero, which is better or which would you prefer to do as a best practice? ...simply clear storage? XC STRGLEN,STRGLEN FOR USED STRING LENGTH COUNTER ...or clear a register and save to storage? XR R5,R5 STARTING AT ZERO STH R5,STRGLEN SET USED STRING LENGTH COUNTER ...or use an immediate value and save to storage? LHI R5,0 STARTING AT ZERO STH R5,STRGLEN SET USED STRING LENGTH COUNTER Sincerely, Dave Clark -- int.ext: 91078 direct: (937) 531-6378 home: (937) 751-3300 Winsupply Group Services 3110 Kettering Boulevard Dayton, Ohio 45439 USA (937) 294-5331
