I would think not much at all (but what I think and $4 will get you a coffee at the Poughkeepsie Starbucks). How hard long could it take to start using all of the bits of the registers for addressing rather than half of them? I would guess it might cause a refresh of the data cache, but that is something that happens all the time.
Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Jerry Callen Sent: Wednesday, May 04, 2016 1:49 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: How expensive is AMODE switching? Before I sit down and write a test program to time it, can anyone tell me how expensive the AMODE switching instructions are (SAM31/SAM64)? I have an AMODE-64 function that needs to execute a short segment of AMODE-31 code in a loop (I know this sounds wacky, but there is actually a reason why I just can't change the AMODE-31 code), and I'm wondering how painful the mode switching will be. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN