Edward Jaffe wrote:
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."
you can get instruction fetch program exception ... separate from instruction
execution program exceptions ... recent post
http://www.garlic.com/~lynn/2006x.html#4 S0C1 with ILC 6
the note in the PoP refers to instruction execution program exceptions (storage
references) ... as opposed to possible instruction fetch program exception.
repeat from previous post/reference:
aka, instruction fetch can page fault ... independent of the
instruction execution page fault.
one of the reasons that 360/67 had an 8-entry associative array (dlat,
tlb, etc) ... was the worse case for "EXECXUTE" of SS instructions
required eight different page addresses.
"EX" (execute) of another instruction
2 pages - instruction start and end (crossing page boundary)
target (SS) instruction
2 pages - instruction start and end (crossing page boundary)
2 pages - operand1 start and end (crossing page boundary)
2 pages - operand2 start and end (crossing page boundary)
------
8 pages
=============
load address instruction fetch could have two page faults (when
instruction crosses page boundary).
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