On Friday I submitted this to IBM: Chapter 12. TSO/E REXX programming services of z/OS 2.5 TSO/E REXX Reference, SA32-0972-50 does not specify whether external functions are called with a 72-byte save area or a 144-byte save area.
-- Shmuel (Seymour J.) Metz http://mason.gmu.edu/~smetz3 ________________________________________ From: IBM Mainframe Assembler List [ASSEMBLER-LIST@LISTSERV.UGA.EDU] on behalf of Gary Weinhold [weinh...@dkl.com] Sent: Monday, January 24, 2022 3:37 PM To: ASSEMBLER-LIST@LISTSERV.UGA.EDU Subject: Re: Saving Caller's 64-bit Regsiters For both VSE and zOS, there is REXX documentation (VSE'sis at https://www.ibm.com/docs/en/zvse/6.2?topic=packages-interface-writing-external-function-subroutine-code that states that on entry to the called routine Register 13 contains the address of a register save area. What it doesn't say is how large that save area is. My assumption would be that it is 18 fullwords, just because it's not documented as being any different in VSE or z/OS and REXX is a 31-bit application. The fact that is not explicitly documented is troublesome, since as was pointed out, the writer of the routine sets the requirements for the users of the routine, and it would be reassuring to know that REXX always meets those requirements. On 2022-01-24 2:14 p.m., Dave Clark wrote: > "IBM Mainframe Assembler List"<ASSEMBLER-LIST@LISTSERV.UGA.EDU> wrote on > 01/24/2022 02:01:29 PM: >> When I'm following save area chains in a dump, starting with R13, I look >> at the second word. If it is an address, I know that the save area at > that >> address is a standard 72-byte save area. If it is F4SA, F5SA, F7SA, or > F8SA, >> offset X'80' from R13 is the address of the save area, and I know what >> format it is. > > That is all well and good -- when you're looking at a dump. But > I'm given to understand that none of that information is helpful when a > called program receives control from a 2nd- or 3rd-party caller (i.e., any > caller not written on-site) in terms of being able to tell how much > storage the caller allocated for the savearea whose address is passed to > the called program. Now, if I've got that wrong, then please enlighten > me. Thanks. > > > Sincerely, > > Dave Clark Gary Weinhold Senior Application Architect DATAKINETICS | Data Performance & Optimization Phone:+1.613.523.5500 x216 Email: weinh...@dkl.com Visit us online at http://secure-web.cisco.com/1cIgNo0EiEMdmDHVJsN4rpstJBctwj_pFa1VvrT-vVAvR8IMa9cRNHGowmgnC-CL_kJe1FRoJ1YoCpJyiS2RQ6X4tcIPJ0-nghTwib08SHqxhTygbcWdPgfY_wQskYU5Ih869H6DQghp_glZWRCEK86S05uXaU1OJEocmUeWRs6t8YAOUQQIdrA51gHjWQ2u_XYf7yRB44yPXrqkF1J3GvU5LMr9HYYsUigfRuvnjmHyUTbQzfiK-qFAri_EPeAgkwAylw2AVzRiqHACJ_VydCY_sXMTi6uJyllFVcSTB22nkIvWEJyHZmqzKxsjcq5Vp6CoahGVTSxC4AUnMJt3QA3Pnt_w-aXxQoqqYW_SOYvXgZi5b3nd87B_oWOXqceP_s8AvTUIVxEqpW4OqOoNce8Md-rSAbTPUDP9in4WBd2Jx0cctJPz8itd7ZJ7-dPwU/http%3A%2F%2Fwww.DKL.com E-mail Notification: The information contained in this email and any attachments is confidential and may be subject to copyright or other intellectual property protection. If you are not the intended recipient, you are not authorized to use or disclose this information, and we request that you notify us by reply mail or telephone and delete the original message from your mail system.
