Re: [boost] Optimized portable isnan, isfinite, fpclassify etc

From: Markus Schöpflin (markus.schoepflin_at_[hidden])
Date: 2006-12-06 04:31:43

Johan Råde wrote:
> Markus Schöpflin wrote:
> 
>> You can't leave out -ieee as 
>> the Alpha needs some special compiler help for conforming IEEE math 
>> handling, the processor itself is only 'mostly conformant'.
> 
> What happens if you leave out -ieee?

fpclassify/test> cxx -D__USE_STD_IOSTREAM -I /vol2/boost/boost test.cpp -lm 
&& ./a.out
fp_traits<float>::type is specialized
fp_traits<double>::type is specialized
fp_traits<long double>::type is generic
sizeof(long double) = 16

Testing float
Assertion failed: std::numeric_limits<T>::has_denorm, file test.cpp, line 100
IOT/Abort trap (core dumped)

> Could you run the inspect tool with -ieee leaved out?

fpclassify/tools/inspect> cxx -D__USE_STD_IOSTREAM -I /vol2/boost/boost 
inspect.cpp -lm && ./a.out

This platform is little-endian.
BOOST_LITTTLE_ENDIAN is defined.

---------- float --------------------

0         00 00 00 00
sn. min   00 00 00 00
-sn. min  80 00 00 00
n. min/2  00 00 00 00
-n. min/2 00 00 00 00
n. min    00 80 00 00
1         3f 80 00 00
3/2       3f c0 00 00
4/3       3f aa aa ab
max       7f 7f ff ff
inf       -- -- -- --
q. nan    -- -- -- --
s. nan    -- -- -- --

---------- double -------------------

0         00 00 00 00 00 00 00 00
sn. min   00 00 00 00 00 00 00 00
-sn. min  80 00 00 00 00 00 00 00
n. min/2  00 00 00 00 00 00 00 00
-n. min/2 00 00 00 00 00 00 00 00
n. min    00 10 00 00 00 00 00 00
1         3f f0 00 00 00 00 00 00
3/2       3f f8 00 00 00 00 00 00
4/3       3f f5 55 55 55 55 55 55
max       7f ef ff ff ff ff ff ff
inf       -- -- -- -- -- -- -- --
q. nan    -- -- -- -- -- -- -- --
s. nan    -- -- -- -- -- -- -- --

---------- long double --------------

0         00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
sn. min   00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
-sn. min  80 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
n. min/2  00 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00
-n. min/2 80 00 80 00 00 00 00 00 00 00 00 00 00 00 00 00
n. min    00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00
1         3f ff 00 00 00 00 00 00 00 00 00 00 00 00 00 00
3/2       3f ff 80 00 00 00 00 00 00 00 00 00 00 00 00 00
4/3       3f ff 55 55 55 55 55 55 55 55 55 55 55 55 55 55
max       7f fe ff ff ff ff ff ff ff ff ff ff ff ff ff ff
inf       -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
q. nan    -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
s. nan    -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --