On Mon, 7 May 2018 08:42:00 -0500, Joel C. Ewing <[email protected]> wrote:
>From the early days of S/360 the high-order bit of a full-word address >pointer has a documented function in standard subroutine linkage of >indicating the last parameter address for subroutines that accept a >variable number of parameters, so even if the architecture might not >restrict using that bit for memory addressing, long-standing software >standards for AMODE24 and AMODE31 do. > >Changing the documented conventions for using the high-order bit of a >32-bit address word This convention *already* has to change for anyone considering moving to AM64 and using 64-bit pointers. There's no reason why it should be mandatory for a full 64-bit application, but disallowed for a 32-bit program. Updating 32-bit programs to conform to AM64 requirements is far less onerous than the massive changes required to create a 64-bit application. > to create a new "AMODE32" would potentially >adversely effect too many things for minimal benefit. Nobody is affected, and the benefit of going from a 2 GiB address space to a 4 GiB address space is a great improvement. BFN. Paul. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
