On Mon, 13 Mar 2017 09:37:15 -0500, Tom Marchant <[email protected]> wrote:
>Unless IBM has changed their direction, 64-bit Cobol will only be useful for >new applications. It will not interact with existing code unless that code is >also converted to AMODE 64. > >The reason for that is that 64-bit Cobol will only be supported with >XPLINK-64. The design of XPLINK-64 makes it incompatible with 31-bit XPLINK. >XPLINK-64 can call non-XPLINK programs, but since it passes a save area >located above the bar, it can only call AMODE 64 programs. > >XPLINK is touted as a performance improvement over standard linkage. The small >improvement in performance makes a big difference with C programs, with its >tendency to create very small subroutines. However, the cost of calling a >program that uses standard linkage is considerably higher. > >Every time an XPLINK program issues a GET or PUT, it has to make that >transition. Unless something really dramatic happens, which means unequivocal benefit for everything from 64-bit addressing for a COBOL program, a reasonable expectation is of at least one to two decades where almost all COBOL programs will continue to use 31-bit addressing. As I understand it, if there are sufficient exceptional cases where clients want 64-bit addressing, and what they ask for is genuinely resolved by 64-bit addressing, and there are enough such requests, then Enterprise COBOL, in a future release, will have the option (probably as a compiler option) to generate 64-bit addressing executable code from COBOL source programs. Enterprise COBOL: no longer only knows about ESA OP-codes; uses Program Objects; has a CALLINTERFACE compiler directive; is geared up to react quickly (relative term) in response to change (V6.1, supporting ARCH(11) was announced on announcement of z13); probably lots of other stuff. V5 wasn't only for 2013, but included a lot of "enablement" for future change. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
