d ===> IMPORT CODE64,'SYSADATA','opendata' ENTRY CELQSTRT NAME TESTPRGD(R) /* //
-----Original Message----- From: IBM Mainframe Discussion List <IBM-MAIN@LISTSERV.UA.EDU> On Behalf Of Barry Lichtenstein Sent: Thursday, August 22, 2019 6:11 PM To: IBM-MAIN@LISTSERV.UA.EDU Subject: Re: 64 bit Assembler DLL app PSECT parm The value of R5 on entry to an XPLINK (which include AMODE 64) function is not the address of the WSA in its entirety (as R0 was in non-XPLINK), but rather the value of the "environment" of that function, which is somewhere within the WSA of that module (executable file). (As implemented I believe it's the same for the entire compilation unit, but the specification is that it corresponds to the function.) The environment address comes from the caller loading the function descriptor -- the R-con/V-con pair for that function. Where V(function) gives the address of the code, R(function) gives the address of the "environment". That then gives the function the base location for its "writable-static area" on entry -- the non-reentrant area containing writable data items and static data items. Thus when an XPLINK function is to call another function (exception OS linkage), it needs a descriptor to do so. As the address of the environment is unique to each instance of the program (LE enclave), the descriptor of a RENT-compiled program has to live in the WSA so that it can be updated with the environment address of the target program, unlike a V-con which can be relocated during load time. (The V-con in the descriptor also needs to be updated in support of DLLs, i.e. if the function being called is not within the calling module). The net of this is that in XPLINK you need the PSECT in concert with the call macro (CELQCALL), and that call macro automatically takes care of allocating the descriptor. The manual says only under the CELQCALL usage notes: 2. This macro requires that a PSECT was defined by the CELQPRLG prolog macro Though I don't see where there is a similar note, CEEPDDA and CEEPLDA also both require a PSECT for XPLINK (perhaps because these macros also work for non-XPLINK DLLs). These allow you to define and reference data items your environment (WSA) which are exportable/importable respectively. On 21 Aug 2019 11:17:24 AM Joseph Reichman <reichman...@gmail.com> wrote: > Just looked thru LE book shelf would be nice If they had programming > examples Or at the very least documentation on the parameters used for > the EDC macros ---------------------------------------------------------------------- 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
