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author | Joseph Myers <joseph@codesourcery.com> | 2015-02-12 19:02:45 +0000 |
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committer | Joseph Myers <joseph@codesourcery.com> | 2015-02-12 19:02:45 +0000 |
commit | 03d95bd48319256bd29cfaece45919fc58bf56cc (patch) | |
tree | 5ed21769ade47b69e555932587a23f69201c7ba6 /ChangeLog | |
parent | 98408b95b155464e760c22dce4842f29499db821 (diff) | |
download | glibc-03d95bd48319256bd29cfaece45919fc58bf56cc.tar.gz glibc-03d95bd48319256bd29cfaece45919fc58bf56cc.tar.xz glibc-03d95bd48319256bd29cfaece45919fc58bf56cc.zip |
Fix exp2 spurious underflows (bug 16560).
This patch fixes the remaining part of bug 16560, spurious underflows from exp2 of arguments close to 0 (when the result is close to 1, so should not underflow), by just using 1+x instead of a more complicated calculation when the argument is sufficiently small. Tested for x86_64, x86 and mips64. [BZ #16560] * math/e_exp2l.c [LDBL_MANT_DIG == 106] (LDBL_EPSILON): Undefine and redefine. (__ieee754_exp2l): Do not multiply small fractional parts by M_LN2l. * sysdeps/i386/fpu/e_exp2l.S (__ieee754_exp2l): Just add 1 to small argument. * sysdeps/ieee754/dbl-64/e_exp2.c (__ieee754_exp2): Likewise. * sysdeps/ieee754/flt-32/e_exp2f.c (__ieee754_exp2f): Likewise. * sysdeps/x86_64/fpu/e_exp2l.S (__ieee754_exp2l): Likewise. * math/auto-libm-test-in: Add more tests of exp2. * math/auto-libm-test-out: Regenerated.
Diffstat (limited to 'ChangeLog')
-rw-r--r-- | ChangeLog | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/ChangeLog b/ChangeLog index d431c29f04..54da8c5fac 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,18 @@ +2015-02-12 Joseph Myers <joseph@codesourcery.com> + + [BZ #16560] + * math/e_exp2l.c [LDBL_MANT_DIG == 106] (LDBL_EPSILON): Undefine + and redefine. + (__ieee754_exp2l): Do not multiply small fractional parts by + M_LN2l. + * sysdeps/i386/fpu/e_exp2l.S (__ieee754_exp2l): Just add 1 to + small argument. + * sysdeps/ieee754/dbl-64/e_exp2.c (__ieee754_exp2): Likewise. + * sysdeps/ieee754/flt-32/e_exp2f.c (__ieee754_exp2f): Likewise. + * sysdeps/x86_64/fpu/e_exp2l.S (__ieee754_exp2l): Likewise. + * math/auto-libm-test-in: Add more tests of exp2. + * math/auto-libm-test-out: Regenerated. + 2015-02-12 Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com> * sysdeps/powerpc/powerpc64/power7/strncpy.S (strncpy): Optimize |