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authorJoseph Myers <joseph@codesourcery.com>2014-05-23 12:07:50 +0000
committerJoseph Myers <joseph@codesourcery.com>2014-05-23 12:07:50 +0000
commitb72592e75fdecb34e2ac5f931730409a1fb68e8a (patch)
tree9a7f71aecd06da02f507abf536a72a1bcbd69209 /math
parent2302d679ce8b36854022207b58e554b3e89dd8c7 (diff)
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Fix log10 (1) in round-downward mode (bug 16977).
As with various other issues of this kind, bug 16977 is log10 (1)
wrongly returning -0 rather than +0 in round-downward mode because of
an implementation effectively in terms of log1p (x - 1).  This patch
fixes the issue in the same way used for log.

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 logl is
essentially the same as the ldbl-128 one).

	[BZ #16977]
	* sysdeps/i386/fpu/e_log10.S (__ieee754_log10): Take absolute
	value when x - 1 is zero.
	* sysdeps/i386/fpu/e_log10f.S (__ieee754_log10f): Likewise.
	* sysdeps/i386/fpu/e_log10l.S (__ieee754_log10l): Likewise.
	* sysdeps/ieee754/ldbl-128/e_log10l.c (__ieee754_log10l): Return
	0.0L for an argument of 1.0L.
	* sysdeps/ieee754/ldbl-128ibm/e_log10l.c (__ieee754_log10l):
	Likewise.
	* sysdeps/x86_64/fpu/e_log10l.S (__ieee754_log10l): Take absolute
	value when x - 1 is zero.
	* math/libm-test.inc (log10_test): Use ALL_RM_TEST.
	* sysdeps/i386/fpu/libm-test-ulps: Update.
	* sysdeps/x86_64/fpu/libm-test-ulps: Likewise.
Diffstat (limited to 'math')
-rw-r--r--math/libm-test.inc4
1 files changed, 1 insertions, 3 deletions
diff --git a/math/libm-test.inc b/math/libm-test.inc
index de7bc8ad94..0d467a2195 100644
--- a/math/libm-test.inc
+++ b/math/libm-test.inc
@@ -7798,9 +7798,7 @@ static const struct test_f_f_data log10_test_data[] =
 static void
 log10_test (void)
 {
-  START (log10, 0);
-  RUN_TEST_LOOP_f_f (log10, log10_test_data, );
-  END;
+  ALL_RM_TEST (log10, 0, log10_test_data, RUN_TEST_LOOP_f_f, END);
 }