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authorDavid S. Miller <davem@davemloft.net>2012-11-16 09:31:38 -0800
committerDavid S. Miller <davem@davemloft.net>2012-11-16 09:31:38 -0800
commit447885ebf1c1fc8adf4084f5e2708ff84d0da43b (patch)
tree95a48aa60e330d4afc6de73d70879e9e52ca47ff /sysdeps/ieee754/ldbl-128
parentbcbf9830b735acdd9b0d49fe96da73dfacfa17d0 (diff)
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Don't generate underflow for very small values in log1pl.
* sysdeps/ieee754/ldbl-128/s_log1pl.c (__log1pl): If xm1 is smaller than LDBL_EPSILON/2.0L, just return xm1.
Diffstat (limited to 'sysdeps/ieee754/ldbl-128')
-rw-r--r--sysdeps/ieee754/ldbl-128/s_log1pl.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/sysdeps/ieee754/ldbl-128/s_log1pl.c b/sysdeps/ieee754/ldbl-128/s_log1pl.c
index 4ecea0f..fad18e9 100644
--- a/sysdeps/ieee754/ldbl-128/s_log1pl.c
+++ b/sysdeps/ieee754/ldbl-128/s_log1pl.c
@@ -138,6 +138,12 @@ __log1pl (long double xm1)
&& (u.parts32.w1 | u.parts32.w2 | u.parts32.w3) == 0)
return xm1;
+ if ((hx & 0x7fffffff) < 0x3f8e0000)
+ {
+ if ((int) xm1 == 0)
+ return xm1;
+ }
+
x = xm1 + 1.0L;
/* log1p(-1) = -inf */