> ITYM bit 0 Nowadays bit 0 is the high-order bit of 64 bits. I mean bit 32, the "first" bit of the low word.
> The high-order bid is always bit 0. Yep. And we have 64 of them nowadays. Charles -----Original Message----- From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] On Behalf Of Paul Gilmartin Sent: Tuesday, February 19, 2019 1:24 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: Any easier way to determine if DD is dummy than GETDSAB? On Tue, 19 Feb 2019 14:47:03 -0500, Steve Smith wrote: >Bit 32 is pervasively used as a flag, most typically the end of a list. As >far as the hardware goes, it is ignored for addressing. I'm not going to >bother looking up the DEVTYPE specifications, but I believe it has a >variable-length parm list. So it would have reason to care. > ITYM bit 0. VL is not supported for 64-bit parameter addresses. From: https://www.ibm.com/support/knowledgecenter/en/SSLTBW_2.3.0/com.ibm.zos.v2r3.idai200/da6i2316.htm VL causes the high-order bit of the last address parameter in the macro expansion to be set to 1. Bits are numbered from left-to-right. The high-order bid is always bit 0. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
