Most of your comments can be addressed simply by:
"But, I do know the current addressing mode."
So, unless you are going to add another addressing mode....
Tony Thigpen
Paul Edwards wrote on 05/06/2018 04:00 PM:
On Sun, 6 May 2018 15:45:31 -0400, Tony Thigpen <[email protected]> wrote:
Just for starters.
1) I am looking at the registers at abend. Is it a 31 bit address with
the high-bit on, or is it a 32 bit address?
If you don't want to debug 32-bit programs
that have 4 GiB of memory available to them,
then simply don't code it. There's no reason
to stop other people from using the full 4 GiB.
You also can't tell whether an address is 31-bit
or a 24-bit address with crud in the top 8 bits.
That's no reason for the 24-bit bar from being
there for eternity.
2) The programmer uses GETMAIN LOC=32 forgetting that he is passing an
address that is in that area to a subprogram that is not 32bit. Oops.
Same as calling an AM24 subroutine from an
AM31 caller. No reason to stick with AM24
for eternity.
3) I am looking at a parameter list with 4 parms. The 2nd and the 4th
have the high-bit on. Is the 2nd parm the last parm or is not but
instead it is a 32 bit address and the 4th parm the last parm?
If you don't want to be confused by parameter
lists then simply never use LOC=32 addresses
in the parameter lists. Use LOC=32 memory
for internal use only.
I am a vendor that writes system software that is called by application
programmers. I am not sure how I would validate that a 32 bit address
was 32 bit and not 31 bit. Or, the reverse.
You can't differentiate between an AM24 or AM31
address either. It is up to the caller to provide
data in the expected AMODE.
IBM has the same problem when somebody calls their services. That is why
the BAR exists.
IBM services that can't accept an AM64 caller
are already documented as such.
As far as I can tell, the BAR exists for the same
reasons that 16 MiB LINE exists - historical
curiosity. No reason to be stuck with that forever.
Most other 32-bit programming environments
allow access to the full 4 GiB and z/Arch is
capable of delivering the same functionality
to z/OS users.
BFN. Paul.
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