From 2dec468fd82c6d968f622c2c519fcb8dc09bddac Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Wed, 18 Dec 2013 11:38:27 +0000 Subject: Fix ldbl-128 logl for subnormals (bug 16338). This patch fixes bug 16338, ldbl-128 logl not handling subnormals (with consequent inaccuracy for lgammal as well). The fix is simply to use __frexpl when determining the exponent, as done already in log2l and log10l. Given the lack of testing of small arguments to any of the log* functions, appropriate tests are added for all of them. Tested x86_64 and x86 and ulps updated accordingly, and spot tests also run for mips64 to confirm the ldbl-128 fix. Note that while this fixes lgammal inaccuracy for small positive arguments, I suspect that there will still be problems with spurious underflows in that case. * sysdeps/ieee754/ldbl-128/e_logl.c (__ieee754_logl): Use __frexpl to determine exponent and adjust argument to have exponent of -1. * math/auto-libm-test-in: Add more tests of log, log10, log1p and log2. * math/auto-libm-test-out: Regenerated. * sysdeps/x86_64/fpu/libm-test-ulps: Update. --- sysdeps/i386/fpu/libm-test-ulps | 3 +++ 1 file changed, 3 insertions(+) (limited to 'sysdeps/i386/fpu') diff --git a/sysdeps/i386/fpu/libm-test-ulps b/sysdeps/i386/fpu/libm-test-ulps index ce4e631..5ed3fee 100644 --- a/sysdeps/i386/fpu/libm-test-ulps +++ b/sysdeps/i386/fpu/libm-test-ulps @@ -6684,6 +6684,9 @@ ldouble: 1 Test "log10 (0x2.b7e151628aed2p+0)": ildouble: 1 ldouble: 1 +Test "log10 (0x4p-128)": +ildouble: 1 +ldouble: 1 Test "log10 (0xcp-4)": ildouble: 1 ldouble: 1 -- cgit v1.1