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author | Ulrich Drepper <drepper@gmail.com> | 2011-10-15 20:47:01 -0400 |
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committer | Ulrich Drepper <drepper@gmail.com> | 2011-10-15 20:47:01 -0400 |
commit | b61099b50a028d3ac69aa9500ffa9871d23e3884 (patch) | |
tree | 9c33a5998b9f0d4a16bd68fb62973d30fd310aab /sysdeps | |
parent | bcf01e6d800e837622ddbc851b42b55fa99e5636 (diff) | |
download | glibc-b61099b50a028d3ac69aa9500ffa9871d23e3884.zip glibc-b61099b50a028d3ac69aa9500ffa9871d23e3884.tar.gz glibc-b61099b50a028d3ac69aa9500ffa9871d23e3884.tar.bz2 |
Add cosh optimized for 64-bit architectures
Diffstat (limited to 'sysdeps')
-rw-r--r-- | sysdeps/ieee754/dbl-64/e_cosh.c | 4 | ||||
-rw-r--r-- | sysdeps/ieee754/dbl-64/wordsize-64/e_cosh.c | 82 |
2 files changed, 82 insertions, 4 deletions
diff --git a/sysdeps/ieee754/dbl-64/e_cosh.c b/sysdeps/ieee754/dbl-64/e_cosh.c index 180ca42..b9f79e4 100644 --- a/sysdeps/ieee754/dbl-64/e_cosh.c +++ b/sysdeps/ieee754/dbl-64/e_cosh.c @@ -10,10 +10,6 @@ * ==================================================== */ -#if defined(LIBM_SCCS) && !defined(lint) -static char rcsid[] = "$NetBSD: e_cosh.c,v 1.7 1995/05/10 20:44:58 jtc Exp $"; -#endif - /* __ieee754_cosh(x) * Method : * mathematically cosh(x) if defined to be (exp(x)+exp(-x))/2 diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/e_cosh.c b/sysdeps/ieee754/dbl-64/wordsize-64/e_cosh.c new file mode 100644 index 0000000..41dc42c --- /dev/null +++ b/sysdeps/ieee754/dbl-64/wordsize-64/e_cosh.c @@ -0,0 +1,82 @@ +/* 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 + * is preserved. + * ==================================================== + */ + +/* __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; + + /* High word of |x|. */ + GET_HIGH_WORD(ix,x); + ix &= 0x7fffffff; + + /* |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; + } + + /* |x| in [22, log(maxdouble)] return half*exp(|x|) */ + if (ix < 0x40862e42) return half*__ieee754_exp(fabs(x)); + + /* |x| in [log(maxdouble), overflowthresold] */ + int64_t fix; + EXTRACT_WORDS64(fix, x); + if (fix <= UINT64_C(0x408633ce8fb9f87d)) { + w = __ieee754_exp(half*fabs(x)); + t = half*w; + 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) |