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[/] [openrisc/] [trunk/] [gnu-old/] [newlib-1.17.0/] [newlib/] [libc/] [sys/] [linux/] [cmath/] [s_csqrt.c] - Blame information for rev 816

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/* Complex square root of double value.
   Copyright (C) 1997, 1998 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Based on an algorithm by Stephen L. Moshier <moshier@world.std.com>.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.
 
   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.
 
   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.
 
   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */
 
#include <complex.h>
#include <math.h>
 
#include "math_private.h"
 
 
__complex__ double
__csqrt (__complex__ double x)
{
  __complex__ double res;
  int rcls = fpclassify (__real__ x);
  int icls = fpclassify (__imag__ x);
 
  if (rcls <= FP_INFINITE || icls <= FP_INFINITE)
    {
      if (icls == FP_INFINITE)
        {
          __real__ res = HUGE_VAL;
          __imag__ res = __imag__ x;
        }
      else if (rcls == FP_INFINITE)
        {
          if (__real__ x < 0.0)
            {
              __real__ res = icls == FP_NAN ? __nan ("") : 0;
              __imag__ res = __copysign (HUGE_VAL, __imag__ x);
            }
          else
            {
              __real__ res = __real__ x;
              __imag__ res = (icls == FP_NAN
                              ? __nan ("") : __copysign (0.0, __imag__ x));
            }
        }
      else
        {
          __real__ res = __nan ("");
          __imag__ res = __nan ("");
        }
    }
  else
    {
      if (icls == FP_ZERO)
        {
          if (__real__ x < 0.0)
            {
              __real__ res = 0.0;
              __imag__ res = __copysign (__ieee754_sqrt (-__real__ x),
                                         __imag__ x);
            }
          else
            {
              __real__ res = fabs (__ieee754_sqrt (__real__ x));
              __imag__ res = __copysign (0.0, __imag__ x);
            }
        }
      else if (rcls == FP_ZERO)
        {
          double r = __ieee754_sqrt (0.5 * fabs (__imag__ x));
 
          __real__ res = __copysign (r, __imag__ x);
          __imag__ res = r;
        }
      else
        {
          double d, r, s;
 
          d = __ieee754_hypot (__real__ x, __imag__ x);
          /* Use the identity   2  Re res  Im res = Im x
             to avoid cancellation error in  d +/- Re x.  */
          if (__real__ x > 0)
            {
              r = __ieee754_sqrt (0.5 * d + 0.5 * __real__ x);
              s = (0.5 * __imag__ x) / r;
            }
          else
            {
              s = __ieee754_sqrt (0.5 * d - 0.5 * __real__ x);
              r = fabs ((0.5 * __imag__ x) / s);
            }
 
          __real__ res = r;
          __imag__ res = __copysign (s, __imag__ x);
        }
    }
 
  return res;
}
weak_alias (__csqrt, csqrt)
#ifdef NO_LONG_DOUBLE
strong_alias (__csqrt, __csqrtl)
weak_alias (__csqrt, csqrtl)
#endif

Line No.	Rev	Author	Line
1	148	jeremybenn	`/* Complex square root of double value.`
2			`Copyright (C) 1997, 1998 Free Software Foundation, Inc.`
3			`This file is part of the GNU C Library.`
4			`Based on an algorithm by Stephen L. Moshier <moshier@world.std.com>.`
5			`Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997.`
6
7			`The GNU C Library is free software; you can redistribute it and/or`
8			`modify it under the terms of the GNU Lesser General Public`
9			`License as published by the Free Software Foundation; either`
10			`version 2.1 of the License, or (at your option) any later version.`
11
12			`The GNU C Library is distributed in the hope that it will be useful,`
13			`but WITHOUT ANY WARRANTY; without even the implied warranty of`
14			`MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU`
15			`Lesser General Public License for more details.`
16
17			`You should have received a copy of the GNU Lesser General Public`
18			`License along with the GNU C Library; if not, write to the Free`
19			`Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA`
20			`02111-1307 USA. */`
21
22			`#include <complex.h>`
23			`#include <math.h>`
24
25			`#include "math_private.h"`
26
27
28			`__complex__ double`
29			`__csqrt (__complex__ double x)`
30			`{`
31			`__complex__ double res;`
32			`int rcls = fpclassify (__real__ x);`
33			`int icls = fpclassify (__imag__ x);`
34
35			`if (rcls <= FP_INFINITE \|\| icls <= FP_INFINITE)`
36			`{`
37			`if (icls == FP_INFINITE)`
38			`{`
39			`__real__ res = HUGE_VAL;`
40			`__imag__ res = __imag__ x;`
41			`}`
42			`else if (rcls == FP_INFINITE)`
43			`{`
44			`if (__real__ x < 0.0)`
45			`{`
46			`__real__ res = icls == FP_NAN ? __nan ("") : 0;`
47			`__imag__ res = __copysign (HUGE_VAL, __imag__ x);`
48			`}`
49			`else`
50			`{`
51			`__real__ res = __real__ x;`
52			`__imag__ res = (icls == FP_NAN`
53			`? __nan ("") : __copysign (0.0, __imag__ x));`
54			`}`
55			`}`
56			`else`
57			`{`
58			`__real__ res = __nan ("");`
59			`__imag__ res = __nan ("");`
60			`}`
61			`}`
62			`else`
63			`{`
64			`if (icls == FP_ZERO)`
65			`{`
66			`if (__real__ x < 0.0)`
67			`{`
68			`__real__ res = 0.0;`
69			`__imag__ res = __copysign (__ieee754_sqrt (-__real__ x),`
70			`__imag__ x);`
71			`}`
72			`else`
73			`{`
74			`__real__ res = fabs (__ieee754_sqrt (__real__ x));`
75			`__imag__ res = __copysign (0.0, __imag__ x);`
76			`}`
77			`}`
78			`else if (rcls == FP_ZERO)`
79			`{`
80			`double r = __ieee754_sqrt (0.5 * fabs (__imag__ x));`
81
82			`__real__ res = __copysign (r, __imag__ x);`
83			`__imag__ res = r;`
84			`}`
85			`else`
86			`{`
87			`double d, r, s;`
88
89			`d = __ieee754_hypot (__real__ x, __imag__ x);`
90			`/* Use the identity 2 Re res Im res = Im x`
91			`to avoid cancellation error in d +/- Re x. */`
92			`if (__real__ x > 0)`
93			`{`
94			`r = __ieee754_sqrt (0.5 * d + 0.5 * __real__ x);`
95			`s = (0.5 * __imag__ x) / r;`
96			`}`
97			`else`
98			`{`
99			`s = __ieee754_sqrt (0.5 * d - 0.5 * __real__ x);`
100			`r = fabs ((0.5 * __imag__ x) / s);`
101			`}`
102
103			`__real__ res = r;`
104			`__imag__ res = __copysign (s, __imag__ x);`
105			`}`
106			`}`
107
108			`return res;`
109			`}`
110			`weak_alias (__csqrt, csqrt)`
111			`#ifdef NO_LONG_DOUBLE`
112			`strong_alias (__csqrt, __csqrtl)`
113			`weak_alias (__csqrt, csqrtl)`
114			`#endif`

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[/] [openrisc/] [trunk/] [gnu-old/] [newlib-1.17.0/] [newlib/] [libc/] [sys/] [linux/] [cmath/] [s_csqrt.c] - Blame information for rev 816