1 /* Compute complex natural logarithm.
2 Copyright (C) 1997-2012 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <http://www.gnu.org/licenses/>. */
22 #include <math_private.h>
25 __complex__
long double
26 __clogl (__complex__
long double x
)
28 __complex__
long double result
;
29 int rcls
= fpclassify (__real__ x
);
30 int icls
= fpclassify (__imag__ x
);
32 if (__builtin_expect (rcls
== FP_ZERO
&& icls
== FP_ZERO
, 0))
34 /* Real and imaginary part are 0.0. */
35 __imag__ result
= signbit (__real__ x
) ? M_PIl
: 0.0;
36 __imag__ result
= __copysignl (__imag__ result
, __imag__ x
);
37 /* Yes, the following line raises an exception. */
38 __real__ result
= -1.0 / fabsl (__real__ x
);
40 else if (__builtin_expect (rcls
!= FP_NAN
&& icls
!= FP_NAN
, 1))
42 /* Neither real nor imaginary part is NaN. */
43 long double absx
= fabsl (__real__ x
), absy
= fabsl (__imag__ x
);
47 if (absx
> LDBL_MAX
/ 2.0L)
50 absx
= __scalbnl (absx
, scale
);
51 absy
= (absy
>= LDBL_MIN
* 2.0L ? __scalbnl (absy
, scale
) : 0.0L);
53 else if (absy
> LDBL_MAX
/ 2.0L)
56 absx
= (absx
>= LDBL_MIN
* 2.0L ? __scalbnl (absx
, scale
) : 0.0L);
57 absy
= __scalbnl (absy
, scale
);
59 else if (absx
< LDBL_MIN
&& absy
< LDBL_MIN
)
61 scale
= LDBL_MANT_DIG
;
62 absx
= __scalbnl (absx
, scale
);
63 absy
= __scalbnl (absy
, scale
);
66 d
= __ieee754_hypotl (absx
, absy
);
68 __real__ result
= __ieee754_logl (d
) - scale
* M_LN2l
;
69 __imag__ result
= __ieee754_atan2l (__imag__ x
, __real__ x
);
73 __imag__ result
= __nanl ("");
74 if (rcls
== FP_INFINITE
|| icls
== FP_INFINITE
)
75 /* Real or imaginary part is infinite. */
76 __real__ result
= HUGE_VALL
;
78 __real__ result
= __nanl ("");
83 weak_alias (__clogl
, clogl
)