diff options
Diffstat (limited to 'newlib/libm/mathfp/s_atangent.c')
| -rw-r--r-- | newlib/libm/mathfp/s_atangent.c | 213 |
1 files changed, 0 insertions, 213 deletions
diff --git a/newlib/libm/mathfp/s_atangent.c b/newlib/libm/mathfp/s_atangent.c deleted file mode 100644 index c6f3c9b..0000000 --- a/newlib/libm/mathfp/s_atangent.c +++ /dev/null @@ -1,213 +0,0 @@ - -/* @(#)z_atangent.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. - ******************************************************************/ - -/* -FUNCTION - <<atan>>, <<atanf>>, <<atan2>>, <<atan2f>>, <<atangent>>, <<atangentf>>---arc tangent - -INDEX - atan2 -INDEX - atan2f -INDEX - atan -INDEX - atanf - -ANSI_SYNOPSIS - #include <math.h> - double atan(double <[x]>); - float atan(float <[x]>); - double atan2(double <[y]>,double <[x]>); - float atan2f(float <[y]>,float <[x]>); - -TRAD_SYNOPSIS - #include <math.h> - double atan2(<[y]>,<[x]>); - double <[y]>; - double <[x]>; - - float atan2f(<[y]>,<[x]>); - float <[y]>; - float <[x]>; - - #include <math.h> - double atan(<[x]>); - double <[x]>; - - float atanf(<[x]>); - float <[x]>; - -DESCRIPTION - -<<atan2>> computes the inverse tangent (arc tangent) of y / x. - -<<atan2f>> is identical to <<atan2>>, save that it operates on <<floats>>. - -<<atan>> computes the inverse tangent (arc tangent) of the input value. - -<<atanf>> is identical to <<atan>>, save that it operates on <<floats>>. - -RETURNS -@ifinfo -<<atan>> returns a value in radians, in the range of -pi/2 to pi/2. -<<atan2>> returns a value in radians, in the range of -pi/2 to pi/2. -@end ifinfo -@tex -<<atan>> returns a value in radians, in the range of $-\pi/2$ to $\pi/2$. -<<atan2>> returns a value in radians, in the range of $-\pi/2$ to $\pi/2$. -@end tex - -PORTABILITY -<<atan>> is ANSI C. <<atanf>> is an extension. -<<atan2>> is ANSI C. <<atan2f>> is an extension. - -*/ - -/****************************************************************** - * Arctangent - * - * Input: - * x - floating point value - * - * Output: - * arctangent of x - * - * Description: - * This routine calculates arctangents. - * - *****************************************************************/ -#include <float.h> -#include "fdlibm.h" -#include "zmath.h" - -#ifndef _DOUBLE_IS_32BITS - -static const double ROOT3 = 1.73205080756887729353; -static const double a[] = { 0.0, 0.52359877559829887308, 1.57079632679489661923, - 1.04719755119659774615 }; -static const double q[] = { 0.41066306682575781263e+2, - 0.86157349597130242515e+2, - 0.59578436142597344465e+2, - 0.15024001160028576121e+2 }; -static const double p[] = { -0.13688768894191926929e+2, - -0.20505855195861651981e+2, - -0.84946240351320683534e+1, - -0.83758299368150059274 }; - -double -_DEFUN (atangent, (double, double, double, int), - double x _AND - double v _AND - double u _AND - int arctan2) -{ - double f, g, R, P, Q, A, res; - int N; - int branch = 0; - int expv, expu; - - /* Preparation for calculating arctan2. */ - if (arctan2) - { - if (u == 0.0) - if (v == 0.0) - { - errno = ERANGE; - return (z_notanum.d); - } - else - { - branch = 1; - res = __PI_OVER_TWO; - } - - if (!branch) - { - int e; - /* Get the exponent values of the inputs. */ - g = frexp (v, &expv); - g = frexp (u, &expu); - - /* See if a divide will overflow. */ - e = expv - expu; - if (e > DBL_MAX_EXP) - { - branch = 1; - res = __PI_OVER_TWO; - } - - /* Also check for underflow. */ - else if (e < DBL_MIN_EXP) - { - branch = 2; - res = 0.0; - } - } - } - - if (!branch) - { - if (arctan2) - f = fabs (v / u); - else - f = fabs (x); - - if (f > 1.0) - { - f = 1.0 / f; - N = 2; - } - else - N = 0; - - if (f > (2.0 - ROOT3)) - { - A = ROOT3 - 1.0; - f = (((A * f - 0.5) - 0.5) + f) / (ROOT3 + f); - N++; - } - - /* Check for values that are too small. */ - if (-z_rooteps < f && f < z_rooteps) - res = f; - - /* Calculate the Taylor series. */ - else - { - g = f * f; - P = (((p[3] * g + p[2]) * g + p[1]) * g + p[0]) * g; - Q = (((g + q[3]) * g + q[2]) * g + q[1]) * g + q[0]; - R = P / Q; - - res = f + f * R; - } - - if (N > 1) - res = -res; - - res += a[N]; - } - - if (arctan2) - { - if (u < 0.0 || branch == 2) - res = __PI - res; - if (v < 0.0 || branch == 1) - res = -res; - } - else if (x < 0.0) - { - res = -res; - } - - return (res); -} - -#endif /* _DOUBLE_IS_32BITS */ |