There have also been vendors who used 1-offset numbering. Sometimes manufacturers used different conventions for different product lines.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Discussion List [IBM-MAIN@LISTSERV.UA.EDU] on behalf of Charles Mills [charl...@mcn.org] Sent: Monday, April 18, 2022 6:17 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Trying to understand SMF30_RAXFLAGS You're right of course. Other systems count bits the other direction. You can make an argument for either approach. - 0 as the high bit corresponds to how we generally represent binary integers, with the high order bit on the left. - 0 as the low bit gives you consistency across 8, 16, 32 and 64 bit operands, and makes the bit numbers correspond to powers of 2. Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Michael Oujesky Sent: Monday, April 18, 2022 2:15 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Trying to understand SMF30_RAXFLAGS My reading of Principals of Operation indicates register documentation has bit 0 as the high order bit, not lower order bit. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
