"At the begining of a rmode64 pgm to look at the register values and register 15 didn’t have the entry point "
Correct. R15 on entry to a 64-bit program will have x'00000000 FFFFF002' - its a flag to say youre running in 64-bit mode. Joe On Sun, Aug 17, 2025 at 11:04 AM Joseph Reichman < [email protected]> wrote: > I inserted a DC H’0’ > At the begining of a rmode64 pgm to look at the register values and > register 15 didn’t have the entry point > > > On Aug 17, 2025, at 11:04 AM, Seymour J Metz <[email protected]> wrote: > > > > Standard linkage is different for AMODE24/31 and AMODE64. An RMODE64 > program should expect R15 to have flag rather than the EP address. > > > > -- > > Shmuel (Seymour J.) Metz > > http://mason.gmu.edu/~smetz3 > > עַם יִשְׂרָאֵל חַי > > נֵ֣צַח יִשְׂרָאֵ֔ל לֹ֥א יְשַׁקֵּ֖ר > > > > > > > > > > ________________________________________ > > From: IBM Mainframe Discussion List <[email protected]> on > behalf of Joe Monk <[email protected]> > > Sent: Sunday, August 17, 2025 11:00 AM > > To: [email protected] <[email protected]> > > Subject: Re: RMODE 64 > > > > > > External Message: Use Caution > > > > > > Standard linkage > > > > Joe > > > >> On Sun, Aug 17, 2025 at 9:52 AM Joseph Reichman < > >> [email protected]> wrote: > >> > >> My only question is when submitting a batch job to execute rmode 64 what > >> is the value > >> > >> Of Register 15 in entry > >> > >>> On Aug 17, 2025, at 10:32 AM, Peter Morrison < > >> [email protected]> wrote: > >>> > >>> People, > >>> > >>> > >>> > >>> I have watched this discussion for several days. I thought I would > weigh > >>> in. I have created and executed programs in RMODE 64. > >>> > >>> > >>> > >>> RMODE 64 has been supported by z/OS for a long time. I am not sure what > >>> level it came in with (someone else can provide that) but all the > >> relevant > >>> items have been changed, as mentioned below. > >>> > >>> > >>> > >>> Note that before I begin to list things, to execute in an RMODE 64 > >>> environment (i.e., located above the 'bar') you *MUST* be in AMODE 64 > (if > >>> you are not sure why, please read the principles of operation. You > *MUST* > >>> also remain in AMODE 64 for as long as the code that is being executed > is > >>> above the bar. > >>> > >>> > >>> > >>> * You can use the assembler to create a CSECT that can be > loaded > >>> into 64-bit storage by using the '<csectname> RMODE 64' statement. > >>> > >>> > >>> > >>> * There is no specific 'xD' ESD entry. Instead, the object > format > >>> has been enhanced to add a bit to the flags field in the ESD which says > >> 'add > >>> 4 to the length of the field'. Thus VD and external AD fields can be > >>> handled. Similarly, the object RLD records also have a flag bit that > says > >>> 'add 4 to the length - allowing an RLD entry for an 8-byte xD. Note > that > >> you > >>> do not need to use GOFF to have RMODE 64 CSECTs. > >>> > >>> > >>> > >>> * When you bind (link-edit) the program, you can specify the > >> binder > >>> option via the JCL Parm field (you can also use an input option, not > >>> discussed here, read the manual). *DO NOT* use 'RMODE=64'. Instead you > >>> *MUST* specify 'RMODEX=64TRUE'. Don't ask me why (RTFM). The resulting > >>> program is an RMODE64 program. > >>> > >>> > >>> > >>> * Note that an RMODE 64 program *DOES NOT* have to be a program > >>> object. The load module format in a PDS (not a PDSE) has been enhanced, > >> The > >>> RMODE in the directory entry has a RMODE64 bit, the CESD entry flags in > >> the > >>> actual load module have a 'add 4 to the length' bit, and the RLD entry > >> flags > >>> in the actual load module have a 'add 4 to the length' bit. > >>> > >>> > >>> > >>> * Program management was enhanced to load RMODE 64 programs > above > >>> the bar. The CDE (still in 24-bit storage) will point to a CDX which > >> point > >>> to a 64-bit extent list, which has 8-byte addresses and lengths. > >>> > >>> > >>> > >>> * The ATTACH[X], LINK[X], XCTL[X], and LOAD facilities all can > >> load > >>> RMODE 64 programs. Whether the parameter list passed to that program > >> will be > >>> correct is another matter (note that the parameter list format depends > on > >>> the AMODE, not the RMODE) - the system doesn't alter the passed R1 > value > >> so > >>> you probably need to specify the correct parameter list format - > >> determining > >>> the target's RMODE (or AMODE) will be fun! (you can't use BLDL, because > >> the > >>> target program could be in the DLPA). I don't know what happens (IPL > >> wait or > >>> ignored) if an RMODE 64 program that is put into PLPA (or MLPA or > FLPA) - > >>> there is no 64-bit xLPA (the DLPA can have RMODE 64 programs in it but > >> is > >>> not built during IPL) and the compressed extent list in the LPDE does > not > >>> have 8-byte addresses and lengths. Note that all RMODE 64 programs > >> *MUST* be > >>> AMODE 64 but the reverse isn't true. (the parameter list format is > based > >> on > >>> the AMODE of the target, not the RMODE) > >>> > >>> > >>> > >>> * The JCL EXEC statement can execute an RMODE 64 program by > >> simply > >>> specifying its name. I don't know whether or not the PARMS passed are > in > >> the > >>> correct format for a AMODE 64 program (does anyone want to test that?). > >>> Under the covers the EXEC statement uses ATTACH[X]. > >>> > >>> > >>> > >>> This list doesn't cover everything, but hopefully covers the main > things. > >>> > >>> > >>> > >>> It's pretty easy to make a program execute in RMODE 64 (as mentioned > >> above, > >>> you *MUST* be in AMODE 64). However, as others have mentioned, only > some > >>> system services allow a user to be in AMODE 64, and even fewer allow a > >> user > >>> to be located above the bar (i.e., RMODE 64). The safest rule is to > >> assume > >>> the AMODE64 and RMODE 64 code cannot use a service unless that service > >>> explicitly says it can. > >>> > >>> > >>> > >>> Peter Morrison > >>> > >>> > >>> > >>> > >>> ---------------------------------------------------------------------- > >>> For IBM-MAIN subscribe / signoff / archive access instructions, > >>> send email to [email protected] with the message: INFO IBM-MAIN > >> > >> ---------------------------------------------------------------------- > >> For IBM-MAIN subscribe / signoff / archive access instructions, > >> send email to [email protected] with the message: INFO IBM-MAIN > >> > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to [email protected] with the message: INFO IBM-MAIN > > > > > > > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > > send email to [email protected] with the message: INFO IBM-MAIN > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
