(j3.2006) (SC22WG5.3627) N1751
Michael Ingrassia
michaeli
Wed Nov 5 19:55:05 EST 2008
There's a premiss in N1751.txt that I'm not sure I believe, although
I may be reading it wrong.
>Segments Pi and Qj are unordered, and it is therefore permitted for a
>processor to execute segment Qj to completion before starting segment
Pi.
I accept that in theory, there is no argument based solely on
segment ordering to disallow a processor to execute segment Qj to completion
before starting segment Pi.
But do we actually say that a processor is permitted to predicate
the start of segment Pi on the completion of a different segment? I
didn't think so. And if not, then doesn't the principle of Get On With It
(or whatever you might call it) say that the processor has to
eventually start Pi? After all, we don't worry that the PRINT will
never happen in
R = SIN(3.04789232)
PRINT *, R
because the processor might never get around to advancing the program
counter.
Maybe the principle is that an implementation risks being incorrect if it
introduces extra segment orderings (Qj must precede Pi)
not implied by the standard. In other words, this is a processor problem
not a user problem.
What am I missing?
--Michael I.
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