From 03d95bd48319256bd29cfaece45919fc58bf56cc Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Thu, 12 Feb 2015 19:02:45 +0000 Subject: 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. --- math/auto-libm-test-in | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'math/auto-libm-test-in') diff --git a/math/auto-libm-test-in b/math/auto-libm-test-in index ad43113fd1..6bcfd54e55 100644 --- a/math/auto-libm-test-in +++ b/math/auto-libm-test-in @@ -938,6 +938,24 @@ exp2 1023 exp2 -1074 exp2 16383 exp2 -16400 +exp2 0x1p-10 +exp2 -0x1p-10 +exp2 0x1p-20 +exp2 -0x1p-20 +exp2 0x1p-30 +exp2 -0x1p-30 +exp2 0x1p-40 +exp2 -0x1p-40 +exp2 0x1p-50 +exp2 -0x1p-50 +exp2 0x1p-60 +exp2 -0x1p-60 +exp2 0x1p-100 +exp2 -0x1p-100 +exp2 min +exp2 -min +exp2 min_subnorm +exp2 -min_subnorm expm1 0 expm1 -0 -- cgit 1.4.1