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authorJoseph Myers <joseph@codesourcery.com>2014-06-10 12:07:15 +0000
committerJoseph Myers <joseph@codesourcery.com>2014-06-10 12:07:15 +0000
commitf8ba1b5654d876c8db4c9a020e6fa976d434f988 (patch)
treef5e34ce57471cbb1c54ec4cd0492b665f94151bb /ChangeLog
parent2c3520d98d9773d9e092196c3c36150244eed1dd (diff)
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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.
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+2014-06-10 Joseph Myers <joseph@codesourcery.com>
+
+ [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.
+
2014-06-09 Bernard Ogden <bernie.ogden@linaro.org>
[BZ #15119]