Steve Kargl a4e4b355f4 The value small=2**-(p+3), where p is the precision, can be determine from ... lgamma(x) = -log(x) - log(1+x) + x*(1-g) + x**2*P(x) with g = 0.57... being the Euler constant and P(x) a polynomial. Substitution of small into the RHS shows that the last 3 terms are negligible in comparison to the leading term. The choice of 3 may be conservative. The value large=2**(p+3) is detemined from Stirling's approximation lgamma(x) = x*(log(x)-1) - log(x)/2 + log(2*pi)/2 + P(1/x)/x Again, substitution of large into the RHS reveals the last 3 terms are negligible in comparison to the leading term. Move the x=+-0 special case into the |x|<small block. In the ld80 and ld128 implementaion, use fdlibm compatible comparisons involving ix, lx, and llx. This replaces several floating point comparisons (some involving fabsl()) and also fixes the special cases x=1 and x=2. While here . Remove unnecessary parentheses. . Fix/improve comments due to the above changes. . Fix nearby whitespace. * src/e_lgamma_r.c: . Sort declaration. . Remove unneeded explicit cast for type conversion. . Replace a double literal constant by an integer literal constant. * src/e_lgammaf_r.c: . Sort declaration. * ld128/e_lgammal_r.c: . Replace a long double literal constant by a double literal constant. * ld80/e_lgammal_r.c: . Remove unused '#include float.h' . Replace a long double literal constant by a double literal constant. Requested by: bde		2014-10-09 22:39:52 +00:00
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amd64	Merge the 386 and amd64 versions of the fenv.h, to make cc -m32	2013-04-21 13:31:55 +00:00
arm	From https://sourceware.org/ml/newlib/2014/msg00113.html	2014-08-14 04:20:13 +00:00
bsdsrc	Fix some non-standard variable declarations.	2011-10-16 05:37:20 +00:00
i387	Merge the 386 and amd64 versions of the fenv.h, to make cc -m32	2013-04-21 13:31:55 +00:00
ld80	The value small=2**-(p+3), where p is the precision, can be determine from	2014-10-09 22:39:52 +00:00
ld128	The value small=2**-(p+3), where p is the precision, can be determine from	2014-10-09 22:39:52 +00:00
man	* Makefile:	2014-09-15 23:21:57 +00:00
mips	Use #include "fenv.h" instead of #include <fenv.h>. This makes it	2011-10-16 05:37:56 +00:00
powerpc	Use #include "fenv.h" instead of #include <fenv.h>. This makes it	2011-10-16 05:37:56 +00:00
sparc64	Remove ia64.	2014-07-07 00:27:09 +00:00
src	The value small=2**-(p+3), where p is the precision, can be determine from	2014-10-09 22:39:52 +00:00
x86	Merge the 386 and amd64 versions of the fenv.h, to make cc -m32	2013-04-21 13:31:55 +00:00
Makefile	* Makefile:	2014-09-15 23:21:57 +00:00
Symbol.map	* Makefile:	2014-09-15 23:21:57 +00:00