> -----Original Message----- > From: IBM Mainframe Discussion List > [mailto:[email protected]] On Behalf Of Peter Relson > Sent: Saturday, July 24, 2010 9:13 AM > To: [email protected] > Subject: Re: LE calling assembler with 64 bit register usage > > As an assembler routine (especially one that is not utilizing LE > services), you have the responsibility to maintain standard register > saving conventions (unless your caller expects otherwise): > making sure > that the return to the caller is with > - low halves of GPRs 2-13 unchanged > - high halves of GPRs 2-14 unchanged ("14" is not a typo) > - ARs 2-13 unchanged. > > How you accomplish that is up to you. There are many ways including > -- use of linkage stack > -- saving and restoring high halves within the section using > them rather than as part of the prolog/epilog. > > Since the post was about using 8-byte GPRs but not AMODE 64, > it is quite feasible to do the saving/restoring outside of the > prolog/epilog.
Is it guaranteed by LE that the services potentilly invoked by CEEENTRY will not violate those conventions? I.E., initial stack frame allocation, extend stack frame, etc.? Otherwise saving/restoring outside of the prolog/epilog would violate the conventions. Just curious. Peter P.S. -- Given how long that z/OS itself has been 64-bit, it is somewhat suprising to me that CEEENTRY and CEETERM do not have an option to save and restore all 64-bit register contents by using an F4SA-format save area, at least, if not F5SA-format. That would make a lot of sense for calling to assembler routines which use "G"rande instructions, and we are talking about an assembler macro here... This message and any attachments are intended only for the use of the addressee and may contain information that is privileged and confidential. If the reader of the message is not the intended recipient or an authorized representative of the intended recipient, you are hereby notified that any dissemination of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by e-mail and delete the message and any attachments from your system. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
