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Re: Bytes order and words order


On Friday, August 23, 2002, at 09:49 AM, Gabriel Dos Reis wrote:

For example, while on a big or little-endian (for both bytes and words)
machine implementing IEEE-754 and using a 64-bit wide double, I could
plugin a generic definition for infinities, QNaN, SNaN, a
port-maintainer for VAX or ARM, for example, would have to give the
appropriate bytes.
The generic definition of qNaN and sNaN is one of the things I
had in mind.  (I don't remember whether there were others, I'm
afraid; I can try to find and check my notes.)  An NaN has an
exponent with all ones and a nonzero mantissa.  My memory is
that the standard doesn't say how to distinguish between a
qNaN and an sNaN, and that this differs.  On the PPC a qNaN
has the most significant fraction bit 1 and an sNaN has 0, and
for MIPS it's the other way around.

			--Matt



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