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Diffstat (limited to 'libm/src/e_cosh.c')
-rw-r--r-- | libm/src/e_cosh.c | 86 |
1 files changed, 0 insertions, 86 deletions
diff --git a/libm/src/e_cosh.c b/libm/src/e_cosh.c deleted file mode 100644 index 40a943a..0000000 --- a/libm/src/e_cosh.c +++ /dev/null @@ -1,86 +0,0 @@ - -/* @(#)e_cosh.c 1.3 95/01/18 */ -/* - * ==================================================== - * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. - * - * Developed at SunSoft, a Sun Microsystems, Inc. business. - * Permission to use, copy, modify, and distribute this - * software is freely granted, provided that this notice - * is preserved. - * ==================================================== - */ - -#ifndef lint -static char rcsid[] = "$FreeBSD: src/lib/msun/src/e_cosh.c,v 1.8 2005/02/04 18:26:05 das Exp $"; -#endif - -/* __ieee754_cosh(x) - * 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 - * 0 <= x <= ln2/2 : cosh(x) := 1 + ------------------- - * 2*exp(x) - * - * exp(x) + 1/exp(x) - * ln2/2 <= x <= 22 : cosh(x) := ------------------- - * 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) - * - * Special cases: - * cosh(x) is |x| if x is +INF, -INF, or NaN. - * only cosh(0)=1 is exact for finite x. - */ - -#include "math.h" -#include "math_private.h" - -static const double one = 1.0, half=0.5, huge = 1.0e300; - -double -__ieee754_cosh(double x) -{ - double t,w; - int32_t ix; - u_int32_t lx; - - /* High word of |x|. */ - 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; */ - if (ix < 0x40360000) { - t = __ieee754_exp(fabs(x)); - return half*t+half/t; - } - - /* |x| in [22, log(maxdouble)] return half*exp(|x|) */ - if (ix < 0x40862E42) return half*__ieee754_exp(fabs(x)); - - /* |x| in [log(maxdouble), overflowthresold] */ - GET_LOW_WORD(lx,x); - if (ix<0x408633CE || - ((ix==0x408633ce)&&(lx<=(u_int32_t)0x8fb9f87d))) { - w = __ieee754_exp(half*fabs(x)); - t = half*w; - return t*w; - } - - /* |x| > overflowthresold, cosh(x) overflow */ - return huge*huge; -} |