On Thu, 30 Mar 2023 23:39:30 +0200, Bernd Oppolzer wrote: > >"call by value" in my understanding means, that values are passed, not >addressed. >With the mainframe (or z/OS and CMS) linkage convention, this means, >that values >and not addresses are in the reg1 parameter list. > What happens if there are more value parameters than the total capacity of registers? (But do I misunderstand? Is the "reg1 parameter list" not actual registers but the storage addressed by GR1 in the CALL macrlo? If so, it's no practical limit.)
>see above. Because the values entered into the reg1 list "by value" can >be negative integers >(or other types, which need more that 4 bytes), the VL convention cannot >be used by C callers > Hmmm. In <https://www.ibm.com/docs/en/zos/2.5.0?topic=programs-calling-c-code-from-assembler-c-example> I see: EDCPRLG LA 1,ADDR_BLK parameter address block in r1 L 15,=V(@PRINTF4) address of routine BALR 14,15 call @PRINTF4 EDCEPIL ADDR_BLK DC A(FMTSTR) parameter address block with.. DC A(X'80000000'+INTVAL) ..high bit on the last address * ... INTVAL DC F'222' The integer value displayed * Isn't the "X'80000000'" setting the VL bit? (I note that's a CD not an EQU. But the reg1 PL contains an address not a value.) Again, either the caller or the called routine could be able to convert addresses to values. -- gil ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
