Re: I vote NO on motion 21...
Am 05.12.2010 04:15, schrieb Dan Zuras Intervals:
Folks,
I vote NO on motion 21.
My reason has nothing to do with the set of
comparisons proposed. Any reasonable set is
fine with me.
The reason I vote NO is that the motion is
written in a manner that suggests (or even
implies) the existence of state attached to
the act of making a comparison.
We wrote comparisons in a similar manner in
754-1985& it led to implementers actually
CREATING such state as 4 global variable
bits usually in a PSW attached to the thread
of execution in question.
At the time& in the era of 4 MegaHz 8-bit
microprocessors that implemented their
floating-point in software more often than
not, this was not considered bad.
But in the years that have followed it has
become clear that requiring state is a bad
thing in the era of multi threaded multi
GigaHz 32 or 64 bit microprocessors with
multiple on chip floating-point units. It
creates an interlock choke point similar to
a branch that slows everything down& makes
added headaches for the hardware designer.
And, for us, it will delay the acceptance
of 1788 into general hardware use.
But all is not lost.
It would be sufficient to rewrite motion 21
to describe the list of comparisons only.
Any organization of those comparisons into a
system that requires 13 states to describe it
(such as tables 1& 2& the language that goes
with them) should be left out or, at the very
least, relegated to an informative annex.
If this were done I would change my vote to
YES.
Yours,
Dan
Dear Dan, P1788,
as you can see in the motion text there is no requirement for global state.
>>>>
Motion 21
"P1788 should provide access to the states of the interval overlapping
relation. In particular it should provide a function on two intervals a
and b whose range is the set of 13 states defined by tables 1 and 2.
Additionally the functionality of the abstract data type IOV described
by table 8 in section 5 of the position paper should be available.
For full flexibility the atomic operations should be available as
comparisons, see Table 9."
This motion is to be understood as a supplement to motion 13.04.
The advantages are outlined in the position paper that serves as
rationale for the motion.
<<<<
As Nate indicated in his vote an abstract data type is used.
Jürgen & Marco
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