IEFSD095 is still part of z/OS and has not been changed, so it still has BXH instructions which use register 5 for both operands.
Jim Mulder -----Original Message----- From: IBM Mainframe Assembler List <ASSEMBLER-LIST@LISTSERV.UGA.EDU> On Behalf Of Mike Kerford-Byrnes Sent: Wednesday, December 11, 2024 8:33 PM To: ASSEMBLER-LIST@LISTSERV.UGA.EDU Subject: BXLE/BXH I may be mistaken, but I do recall that IEFSD095 - the code that produced the Block letters for printout separator pages - used the same register for the operands in a BXLE??BXH to generate the block letters from a bit map coded inline. I also recall a rumour from someone who had found the source code that there were at least 2 pages of comments explaining the instruction operation. But it was a looooong time ago, and I may have "misremembered". Perhaps someone with access to the OS/360 source (Hercules project?) may be able to confirm/deny/modify. All corrections welcome, if only to repair crusty brain cells! Mike Kerford-Byrnes
