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[/] [openrisc/] [trunk/] [gnu-src/] [newlib-1.18.0/] [newlib/] [libm/] [mathfp/] [s_sineh.c] - Rev 301
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/* @(#)z_sineh.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 <<sinh>>, <<sinhf>>, <<cosh>>, <<coshf>>, <<sineh>>---hyperbolic sine or cosine INDEX sinh INDEX sinhf INDEX cosh INDEX coshf ANSI_SYNOPSIS #include <math.h> double sinh(double <[x]>); float sinhf(float <[x]>); double cosh(double <[x]>); float coshf(float <[x]>); TRAD_SYNOPSIS #include <math.h> double sinh(<[x]>) double <[x]>; float sinhf(<[x]>) float <[x]>; double cosh(<[x]>) double <[x]>; float coshf(<[x]>) float <[x]>; DESCRIPTION <<sinh>> and <<cosh>> compute the hyperbolic sine or cosine of the argument <[x]>. Angles are specified in radians. <<sinh>>(<[x]>) is defined as @ifnottex . (exp(<[x]>) - exp(-<[x]>))/2 @end ifnottex @tex $${e^x - e^{-x}}\over 2$$ @end tex <<cosh>> is defined as @ifnottex . (exp(<[x]>) - exp(-<[x]>))/2 @end ifnottex @tex $${e^x + e^{-x}}\over 2$$ @end tex <<sinhf>> and <<coshf>> are identical, save that they take and returns <<float>> values. RETURNS The hyperbolic sine or cosine of <[x]> is returned. When the correct result is too large to be representable (an overflow), the functions return <<HUGE_VAL>> with the appropriate sign, and sets the global value <<errno>> to <<ERANGE>>. PORTABILITY <<sinh>> is ANSI C. <<sinhf>> is an extension. <<cosh>> is ANSI C. <<coshf>> is an extension. */ /****************************************************************** * Hyperbolic Sine * * Input: * x - floating point value * * Output: * hyperbolic sine of x * * Description: * This routine calculates hyperbolic sines. * *****************************************************************/ #include <float.h> #include "fdlibm.h" #include "zmath.h" static const double q[] = { -0.21108770058106271242e+7, 0.36162723109421836460e+5, -0.27773523119650701667e+3 }; static const double p[] = { -0.35181283430177117881e+6, -0.11563521196851768270e+5, -0.16375798202630751372e+3, -0.78966127417357099479 }; static const double LNV = 0.6931610107421875000; static const double INV_V2 = 0.24999308500451499336; static const double V_OVER2_MINUS1 = 0.13830277879601902638e-4; double _DEFUN (sineh, (double, int), double x _AND int cosineh) { double y, f, P, Q, R, res, z, w; int sgn = 1; double WBAR = 18.55; /* Check for special values. */ switch (numtest (x)) { case NAN: errno = EDOM; return (x); case INF: errno = ERANGE; return (ispos (x) ? z_infinity.d : -z_infinity.d); } y = fabs (x); if (!cosineh && x < 0.0) sgn = -1; if ((y > 1.0 && !cosineh) || cosineh) { if (y > BIGX) { w = y - LNV; /* Check for w > maximum here. */ if (w > BIGX) { errno = ERANGE; return (x); } z = exp (w); if (w > WBAR) res = z * (V_OVER2_MINUS1 + 1.0); } else { z = exp (y); if (cosineh) res = (z + 1 / z) / 2.0; else res = (z - 1 / z) / 2.0; } if (sgn < 0) res = -res; } else { /* Check for y being too small. */ if (y < z_rooteps) { res = x; } /* Calculate the Taylor series. */ else { f = x * x; Q = ((f + q[2]) * f + q[1]) * f + q[0]; P = ((p[3] * f + p[2]) * f + p[1]) * f + p[0]; R = f * (P / Q); res = x + x * R; } } return (res); }
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