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[/] [or1k/] [trunk/] [newlib/] [newlib/] [libm/] [mathfp/] [sf_sine.c] - Blame information for rev 1774

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/* @(#)z_sinef.c 1.0 98/08/13 */
/******************************************************************
 * The following routines are coded directly from the algorithms
 * and coefficients given in "Software Manual for the Elementary
 * Functions" by William J. Cody, Jr. and William Waite, Prentice
 * Hall, 1980.
 ******************************************************************/
/******************************************************************
 * sine generator
 *
 * Input:
 *   x - floating point value
 *   cosine - indicates cosine value
 *
 * Output:
 *   Sine of x.
 *
 * Description:
 *   This routine calculates sines and cosines.
 *
 *****************************************************************/
 
#include "fdlibm.h"
#include "zmath.h"
 
static const float HALF_PI = 1.570796326;
static const float ONE_OVER_PI = 0.318309886;
static const float r[] = { -0.1666665668,
                            0.8333025139e-02,
                           -0.1980741872e-03,
                            0.2601903036e-5 };
 
float
_DEFUN (sinef, (float, int),
        float x _AND
        int cosine)
{
  int sgn, N;
  float y, XN, g, R, res;
  float YMAX = 210828714.0;
 
  switch (numtestf (x))
    {
      case NAN:
        errno = EDOM;
        return (x);
      case INF:
        errno = EDOM;
        return (z_notanum_f.f);
    }
 
  /* Use sin and cos properties to ease computations. */
  if (cosine)
    {
      sgn = 1;
      y = fabsf (x) + HALF_PI;
    }
  else
    {
      if (x < 0.0)
        {
          sgn = -1;
          y = -x;
        }
      else
        {
          sgn = 1;
          y = x;
        }
    }
 
  /* Check for values of y that will overflow here. */
  if (y > YMAX)
    {
      errno = ERANGE;
      return (x);
    }
 
  /* Calculate the exponent. */
  if (y < 0.0)
    N = (int) (y * ONE_OVER_PI - 0.5);
  else
    N = (int) (y * ONE_OVER_PI + 0.5);
  XN = (float) N;
 
  if (N & 1)
    sgn = -sgn;
 
  if (cosine)
    XN -= 0.5;
 
  y = fabsf (x) - XN * __PI;
 
  if (-z_rooteps_f < y && y < z_rooteps_f)
    res = y;
 
  else
    {
      g = y * y;
 
      /* Calculate the Taylor series. */
      R = (((r[3] * g + r[2]) * g + r[1]) * g + r[0]) * g;
 
      /* Finally, compute the result. */
      res = y + y * R;
    }
 
  res *= sgn;
 
  return (res);
}

Line No.	Rev	Author	Line
1	56	joel
2			`/* @(#)z_sinef.c 1.0 98/08/13 */`
3			`/******************************************************************`
4			`* The following routines are coded directly from the algorithms`
5			`* and coefficients given in "Software Manual for the Elementary`
6			`* Functions" by William J. Cody, Jr. and William Waite, Prentice`
7			`* Hall, 1980.`
8			`******************************************************************/`
9			`/******************************************************************`
10			`* sine generator`
11			`*`
12			`* Input:`
13			`* x - floating point value`
14			`* cosine - indicates cosine value`
15			`*`
16			`* Output:`
17			`* Sine of x.`
18			`*`
19			`* Description:`
20			`* This routine calculates sines and cosines.`
21			`*`
22			`*****************************************************************/`
23
24			`#include "fdlibm.h"`
25			`#include "zmath.h"`
26
27			`static const float HALF_PI = 1.570796326;`
28			`static const float ONE_OVER_PI = 0.318309886;`
29			`static const float r[] = { -0.1666665668,`
30			`0.8333025139e-02,`
31			`-0.1980741872e-03,`
32			`0.2601903036e-5 };`
33
34			`float`
35			`_DEFUN (sinef, (float, int),`
36			`float x _AND`
37			`int cosine)`
38			`{`
39			`int sgn, N;`
40			`float y, XN, g, R, res;`
41			`float YMAX = 210828714.0;`
42
43			`switch (numtestf (x))`
44			`{`
45			`case NAN:`
46			`errno = EDOM;`
47			`return (x);`
48			`case INF:`
49			`errno = EDOM;`
50			`return (z_notanum_f.f);`
51			`}`
52
53			`/* Use sin and cos properties to ease computations. */`
54			`if (cosine)`
55			`{`
56			`sgn = 1;`
57			`y = fabsf (x) + HALF_PI;`
58			`}`
59			`else`
60			`{`
61			`if (x < 0.0)`
62			`{`
63			`sgn = -1;`
64			`y = -x;`
65			`}`
66			`else`
67			`{`
68			`sgn = 1;`
69			`y = x;`
70			`}`
71			`}`
72
73			`/* Check for values of y that will overflow here. */`
74			`if (y > YMAX)`
75			`{`
76			`errno = ERANGE;`
77			`return (x);`
78			`}`
79
80			`/* Calculate the exponent. */`
81			`if (y < 0.0)`
82			`N = (int) (y * ONE_OVER_PI - 0.5);`
83			`else`
84			`N = (int) (y * ONE_OVER_PI + 0.5);`
85			`XN = (float) N;`
86
87			`if (N & 1)`
88			`sgn = -sgn;`
89
90			`if (cosine)`
91			`XN -= 0.5;`
92
93			`y = fabsf (x) - XN * __PI;`
94
95			`if (-z_rooteps_f < y && y < z_rooteps_f)`
96			`res = y;`
97
98			`else`
99			`{`
100			`g = y * y;`
101
102			`/* Calculate the Taylor series. */`
103			`R = (((r[3] * g + r[2]) * g + r[1]) * g + r[0]) * g;`
104
105			`/* Finally, compute the result. */`
106			`res = y + y * R;`
107			`}`
108
109			`res *= sgn;`
110
111			`return (res);`
112			`}`

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[/] [or1k/] [trunk/] [newlib/] [newlib/] [libm/] [mathfp/] [sf_sine.c] - Blame information for rev 1774