I'm confused. Is the hole between 2GB & 4GB for all addresses, or just
those in CSA? I thought this thread was only about CSA.
Eric Bielefeld
Sr. z/OS Systems Programmer
Milwaukee, Wisconsin
414-475-7434
----- Original Message -----
From: "Craddock, Chris" <[EMAIL PROTECTED]>
The result of this purely optional, yet extremely wise, design
decision,
is that a 32-bit address word with the high order bit set -- either
accidentally or intentionally -- will cause an 0C4 abend when
processed
by a 64-bit mode program. No need for luck or a smiling deity,. It is
the stated policy of the z/OS operating system that such addresses are
guaranteed never to be valid. Hallelujah!
I would add "what he said" :-) but it might help to add a little visual
to illustrate the point. As we all know, the high order bit has always
been used to signal the last address in a parameter list. This
convention was always a bad idea, but arguably it saved a byte or two in
antediluvian times.
SNIP
CC
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