2aa62f2bc9
This set of three packages: AppPkg, StdLib, StdLibPrivateInternalFiles; contains the implementation of libraries based upon non-UEFI standards such as ISO/IEC-9899, the library portion of the C Language Standard, POSIX, etc. AppPkg contains applications that make use of the standard libraries defined in the StdLib Package. StdLib contains header (include) files and the implementations of the standard libraries. StdLibPrivateInternalFiles contains files for the exclusive use of the library implementations in StdLib. These files should never be directly referenced from applications or other code. git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@11600 6f19259b-4bc3-4df7-8a09-765794883524
92 lines
2.7 KiB
C
92 lines
2.7 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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#include <LibConfig.h>
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#include <sys/EfiCdefs.h>
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#if defined(LIBM_SCCS) && !defined(lint)
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__RCSID("$NetBSD: e_cosh.c,v 1.11 2002/05/26 22:01:49 wiz Exp $");
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#endif
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#if defined(_MSC_VER) /* Handle Microsoft VC++ compiler specifics. */
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// C4756: overflow in constant arithmetic
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#pragma warning ( disable : 4756 )
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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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static const double one = 1.0, half=0.5, huge = 1.0e300;
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double
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__ieee754_cosh(double x)
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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 ||
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((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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