Re: is order urgent doubt

In article <lnej7bhm3l.fsf@xxxxxxxxxxxxxxx>,
Keith Thompson <kst-u@xxxxxxx> wrote:

How is a pair of doubles used to represent a single floating-point
number anyway?

One particular implementation:

http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi?coll=0650&db=man&fname=/usr/share/catman/p_man/cat3/standard/math.z&srch=math


Long double arithmetic is supported by the compiler. The
representation used is not IEEE compliant; long doubles are
represented on this system as the sum or difference of two doubles,
normalized so that the smaller double is <= .5 ULP of the larger.
This is equivalent to a 107 bit mantissa with an 11 bit biased
exponent (bias = 1023), and 1 sign bit. In terms of decimal
precision, this is approximately 34 decimal digits.

Long double constants are coded as double precision constants followed
by the letter 'l' (upper or lower case). The largest (finite) long
double constant is 1.797693134862315807937289714053023e308L.

The smallest long double precision constant is
4.940656458412465441765687928682213e-324L.

Long doubles less than 1.805194375864829576069262081173746e-276L may
require a double denormal in their representation and therefore
contain less than 107 bits precision.

Long double NaNs and (signed) infinities are supported by the
compiler. Long double infinity is represented as the sum of a double
infinity and a double zero; similarly for NaNs.

--
"The shallow murmur, but the deep are dumb." -- Sir Walter Raleigh
.

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