diff options
Diffstat (limited to 'math/s_cacosh.c')
| -rw-r--r-- | math/s_cacosh.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/math/s_cacosh.c b/math/s_cacosh.c index 95bf005cd3..ef49088c3d 100644 --- a/math/s_cacosh.c +++ b/math/s_cacosh.c @@ -1,5 +1,5 @@ /* Return arc hyperbole cosine for double value. - Copyright (C) 1997, 2006, 2011 Free Software Foundation, Inc. + Copyright (C) 1997-2012 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. @@ -66,9 +66,13 @@ __cacosh (__complex__ double x) } /* The factor 16 is just a guess. */ else if (16.0 * fabs (__imag__ x) < fabs (__real__ x)) - /* Kahan's formula which avoid cancellation through subtraction in - some cases. */ - res = 2.0 * __clog (__csqrt ((x + 1.0) / 2.0) + __csqrt ((x - 1.0) / 2.0)); + { + /* Kahan's formula which avoid cancellation through subtraction in + some cases. */ + res = 2.0 * __clog (__csqrt ((x + 1.0) / 2.0) + __csqrt ((x - 1.0) / 2.0)); + if (signbit (__real__ res)) + __real__ res = 0.0; + } else { __complex__ double y; |