glibc/sysdeps/ieee754
Joseph Myers f8ba1b5654 Fix log2 (1) in round-downward mode (bug 17042).
As with other issues of this kind, bug 17042 is log2 (1) wrongly
returning -0 instead of +0 in round-downward mode because of
implementations effectively in terms of log1p (x - 1).  This patch
fixes the issue in the same way used for log and log10.

Tested x86_64 and x86 and ulps updated accordingly.  Also tested for
mips64 to confirm a fix was needed for ldbl-128 and to validate that
fix (also applied to ldbl-128ibm since that version of log2l is
essentially the same as the ldbl-128 one).

	[BZ #17042]
	* sysdeps/i386/fpu/e_log2.S (__ieee754_log2): Take absolete value
	when x - 1 is zero.
	* sysdeps/i386/fpu/e_log2f.S (__ieee754_log2f): Likewise.
	* sysdeps/i386/fpu/e_log2l.S (__ieee754_log2l): Likewise.
	* sysdeps/ieee754/ldbl-128/e_log2l.c (__ieee754_log2l): Return
	0.0L for an argument of 1.0L.
	* sysdeps/ieee754/ldbl-128ibm/e_log2l.c (__ieee754_log2l):
	Likewise.
	* sysdeps/x86_64/fpu/e_log2l.S (__ieee754_log2l): Take absolute
	value when x - 1 is zero.
	* math/libm-test.inc (log2_test): Use ALL_RM_TEST.
	* sysdeps/i386/fpu/libm-test-ulps: Update.
	* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
2014-06-10 12:07:15 +00:00
..
bits Update copyright notices with scripts/update-copyrights 2014-01-01 22:00:23 +10:00
dbl-64 Fix erf underflow handling near 0 (bug 16516). 2014-05-14 12:34:03 +00:00
flt-32 Fix excessive ULP for y1_upward (0x2p+0) in test-float and test-ifloat. 2014-05-31 20:05:00 -07:00
ldbl-64-128 Update copyright notices with scripts/update-copyrights 2014-01-01 22:00:23 +10:00
ldbl-96 Fix acosh (1) in round-downward mode (bug 16927). 2014-05-14 12:35:40 +00:00
ldbl-128 Fix log2 (1) in round-downward mode (bug 17042). 2014-06-10 12:07:15 +00:00
ldbl-128ibm Fix log2 (1) in round-downward mode (bug 17042). 2014-06-10 12:07:15 +00:00
ldbl-opt Update copyright notices with scripts/update-copyrights 2014-01-01 22:00:23 +10:00
ieee754.h Update copyright notices with scripts/update-copyrights 2014-01-01 22:00:23 +10:00
k_standard.c Fix Bessel function error handling (bug 6807, bug 15901). 2013-12-04 14:39:37 +00:00
Makefile Update. 2000-02-26 01:21:37 +00:00
s_lib_version.c Remove trailing whitespace. 2013-06-05 20:44:03 +00:00
s_matherr.c Use <> for math.h and math_private.h everywhere. 2012-03-09 16:09:10 -08:00
s_signgam.c Use <> for math.h and math_private.h everywhere. 2012-03-09 16:09:10 -08:00
support.c Fix leading whitespaces. 2013-06-06 20:36:07 +02:00