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Re: Loop unrolling
- To: kaz at espresso dot cafe dot net
- Subject: Re: Loop unrolling
- From: Martin von Loewis <martin at mira dot isdn dot cs dot tu-berlin dot de>
- Date: Fri, 5 Jun 1998 00:42:10 +0200
- CC: amylaar at cygnus dot co dot uk, egcs at cygnus dot com
- References: <Pine.LNX.3.95.980604044030.14158B-100000@latte.cafe.net>
> Is that from the C++ DWP?
Yes. The concepts (sequence point, side effect) are borrowed from C++,
though.
> How does it define observable behavior?
>> The observable behavior of the abstract machine is its sequence of
>> reads and writes to volatile data and calls to library I/O
>> functions.6)
with footnote 6:
>> An implementation can offer additional library I/O functions as an
>> extension. Implementations that do so should treat calls to those
>> functions as ''observable behavior'' as well.
The relation to sequence points is explained as
>> A conforming implementation executing a wellformed program shall
>> produce the same observable behavior as one of the possible
>> execution sequences of the corresponding instance of the abstract
>> machine with the same program and the same input.
> Who is the observer?
This standard does not deal with human-machine interaction. However,
the intent is clear: Observable behaviour really happens, and can be
observed by anyone using the conforming implementation.
Martin