6796bc807a
1998-09-06 09:53 -0400 Zack Weinberg <zack@rabi.phys.columbia.edu> * Makeconfig (+gccwarn): Remove -Wno-parentheses. * elf/dl-open.c: Quiet -Wparentheses warnings. * iconvdata/johab.c: Likewise. * iconvdata/uhc.c: Likewise. * inet/inet_net.c: Likewise. * io/fts.c: Likewise. * locale/newlocale.c: Likewise. * misc/getttyent.c: Likewise. * misc/mntent_r.c: Likewise. * misc/ttyslot.c: Likewise. * nscd/nscd_conf.c: Likewise. * nss/nsswitch.c: Likewise. * resolv/gethnamaddr.c: Likewise. * resolv/nsap_addr.c: Likewise. * resolv/res_debug.c: Likewise. * stdio-common/_itoa.c: Likewise. * stdlib/strtod.c: Likewise. * string/strverscmp.c: Likewise. * sunrpc/svc.c: Likewise. * sysdeps/libm-ieee754/e_cosh.c: Likewise. * sysdeps/libm-ieee754/e_gamma_r.c: Likewise. * sysdeps/libm-ieee754/e_sinh.c: Likewise. * sysdeps/posix/getaddrinfo.c: Likewise. * include/dlfcn.h: Likewise. * elf/dlfcn.h: Declare dladdr only for __USE_GNU. Define RTLD_DEFAULT.
93 lines
2.5 KiB
C
93 lines
2.5 KiB
C
/* @(#)e_cosh.c 5.1 93/09/24 */
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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#if defined(LIBM_SCCS) && !defined(lint)
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static char rcsid[] = "$NetBSD: e_cosh.c,v 1.7 1995/05/10 20:44:58 jtc Exp $";
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#endif
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/* __ieee754_cosh(x)
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* Method :
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* mathematically cosh(x) if defined to be (exp(x)+exp(-x))/2
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* 1. Replace x by |x| (cosh(x) = cosh(-x)).
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* 2.
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* [ exp(x) - 1 ]^2
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* 0 <= x <= ln2/2 : cosh(x) := 1 + -------------------
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* 2*exp(x)
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*
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* exp(x) + 1/exp(x)
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* ln2/2 <= x <= 22 : cosh(x) := -------------------
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* 2
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* 22 <= x <= lnovft : cosh(x) := exp(x)/2
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* lnovft <= x <= ln2ovft: cosh(x) := exp(x/2)/2 * exp(x/2)
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* ln2ovft < x : cosh(x) := huge*huge (overflow)
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*
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* Special cases:
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* cosh(x) is |x| if x is +INF, -INF, or NaN.
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* only cosh(0)=1 is exact for finite x.
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*/
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#include "math.h"
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#include "math_private.h"
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#ifdef __STDC__
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static const double one = 1.0, half=0.5, huge = 1.0e300;
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#else
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static double one = 1.0, half=0.5, huge = 1.0e300;
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#endif
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#ifdef __STDC__
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double __ieee754_cosh(double x)
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#else
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double __ieee754_cosh(x)
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double x;
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#endif
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{
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double t,w;
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int32_t ix;
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u_int32_t lx;
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/* High word of |x|. */
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GET_HIGH_WORD(ix,x);
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ix &= 0x7fffffff;
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/* x is INF or NaN */
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if(ix>=0x7ff00000) return x*x;
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/* |x| in [0,0.5*ln2], return 1+expm1(|x|)^2/(2*exp(|x|)) */
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if(ix<0x3fd62e43) {
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t = __expm1(fabs(x));
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w = one+t;
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if (ix<0x3c800000) return w; /* cosh(tiny) = 1 */
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return one+(t*t)/(w+w);
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}
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/* |x| in [0.5*ln2,22], return (exp(|x|)+1/exp(|x|)/2; */
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if (ix < 0x40360000) {
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t = __ieee754_exp(fabs(x));
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return half*t+half/t;
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}
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/* |x| in [22, log(maxdouble)] return half*exp(|x|) */
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if (ix < 0x40862e42) return half*__ieee754_exp(fabs(x));
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/* |x| in [log(maxdouble), overflowthresold] */
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GET_LOW_WORD(lx,x);
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if (ix<0x408633ce || ((ix==0x408633ce)&&(lx<=(u_int32_t)0x8fb9f87d))) {
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w = __ieee754_exp(half*fabs(x));
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t = half*w;
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return t*w;
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}
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/* |x| > overflowthresold, cosh(x) overflow */
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return huge*huge;
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}
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