diff options
Diffstat (limited to 'sysdeps/ieee754/dbl-64/e_cosh.c')
| -rw-r--r-- | sysdeps/ieee754/dbl-64/e_cosh.c | 60 |
1 files changed, 27 insertions, 33 deletions
diff --git a/sysdeps/ieee754/dbl-64/e_cosh.c b/sysdeps/ieee754/dbl-64/e_cosh.c index 65106b9989..180ca42881 100644 --- a/sysdeps/ieee754/dbl-64/e_cosh.c +++ b/sysdeps/ieee754/dbl-64/e_cosh.c @@ -1,11 +1,11 @@ -/* @(#)e_cosh.c 5.1 93/09/24 */ +/* Optimized by Ulrich Drepper <drepper@gmail.com>, 2011 */ /* * ==================================================== * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. * * Developed at SunPro, a Sun Microsystems, Inc. business. * Permission to use, copy, modify, and distribute this - * software is freely granted, provided that this notice + * software is freely granted, provided that this notice * is preserved. * ==================================================== */ @@ -15,18 +15,18 @@ static char rcsid[] = "$NetBSD: e_cosh.c,v 1.7 1995/05/10 20:44:58 jtc Exp $"; #endif /* __ieee754_cosh(x) - * Method : + * Method : * mathematically cosh(x) if defined to be (exp(x)+exp(-x))/2 - * 1. Replace x by |x| (cosh(x) = cosh(-x)). - * 2. - * [ exp(x) - 1 ]^2 + * 1. Replace x by |x| (cosh(x) = cosh(-x)). + * 2. + * [ exp(x) - 1 ]^2 * 0 <= x <= ln2/2 : cosh(x) := 1 + ------------------- - * 2*exp(x) + * 2*exp(x) * - * exp(x) + 1/exp(x) + * exp(x) + 1/exp(x) * ln2/2 <= x <= 22 : cosh(x) := ------------------- - * 2 - * 22 <= x <= lnovft : cosh(x) := exp(x)/2 + * 2 + * 22 <= x <= lnovft : cosh(x) := exp(x)/2 * lnovft <= x <= ln2ovft: cosh(x) := exp(x/2)/2 * exp(x/2) * ln2ovft < x : cosh(x) := huge*huge (overflow) * @@ -38,19 +38,11 @@ static char rcsid[] = "$NetBSD: e_cosh.c,v 1.7 1995/05/10 20:44:58 jtc Exp $"; #include "math.h" #include "math_private.h" -#ifdef __STDC__ static const double one = 1.0, half=0.5, huge = 1.0e300; -#else -static double one = 1.0, half=0.5, huge = 1.0e300; -#endif -#ifdef __STDC__ - double __ieee754_cosh(double x) -#else - double __ieee754_cosh(x) - double x; -#endif -{ +double +__ieee754_cosh (double x) +{ double t,w; int32_t ix; u_int32_t lx; @@ -59,19 +51,17 @@ static double one = 1.0, half=0.5, huge = 1.0e300; GET_HIGH_WORD(ix,x); ix &= 0x7fffffff; - /* x is INF or NaN */ - if(ix>=0x7ff00000) return x*x; - - /* |x| in [0,0.5*ln2], return 1+expm1(|x|)^2/(2*exp(|x|)) */ - if(ix<0x3fd62e43) { - t = __expm1(fabs(x)); - w = one+t; - if (ix<0x3c800000) return w; /* cosh(tiny) = 1 */ - return one+(t*t)/(w+w); - } - - /* |x| in [0.5*ln2,22], return (exp(|x|)+1/exp(|x|)/2; */ + /* |x| in [0,22] */ if (ix < 0x40360000) { + /* |x| in [0,0.5*ln2], return 1+expm1(|x|)^2/(2*exp(|x|)) */ + if(ix<0x3fd62e43) { + t = __expm1(fabs(x)); + w = one+t; + if (ix<0x3c800000) return w; /* cosh(tiny) = 1 */ + return one+(t*t)/(w+w); + } + + /* |x| in [0.5*ln2,22], return (exp(|x|)+1/exp(|x|)/2; */ t = __ieee754_exp(fabs(x)); return half*t+half/t; } @@ -87,6 +77,10 @@ static double one = 1.0, half=0.5, huge = 1.0e300; return t*w; } + /* x is INF or NaN */ + if(ix>=0x7ff00000) return x*x; + /* |x| > overflowthresold, cosh(x) overflow */ return huge*huge; } +strong_alias (__ieee754_cosh, __cosh_finite) |