at 03:08 PM, Chuck Arney <[EMAIL PROTECTED]> said:
I think you are still confused. :>) An LA instruction can not
program check.
It can if it straddles page boundaries and the second page is marked
invalid. That's not something that you should see in an application
program.
Untrue! There are no Program Exceptions whatsoever listed for the LA
instruction in PoOp. In fact, it specifically states:
"No storage references for operands take place, and the address is not
inspected for access exceptions."
--------------------------------------<unsnip>------------------------------------
You said it yourself: no references for OPERANDS. But if INSTRUCTION
FETCH has to cross a boundary to an invalid page, an exception can still
occur. The distinction may seem minor but it's every bit as important as
a invalid operand fetch. That particular distinction resulted in major
HW problems for 360/67 owners that happened to use the DAT feature in a
CP67/CMS environment. It was finally isolated by a BAL instruction
generated by the COBOL-F compiler. I was closely involved in that
particular "exercise".
----------------------------------------------------------------------
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO
Search the archives at http://bama.ua.edu/archives/ibm-main.html
