upload sdk

git-svn-id: svn://kolibrios.org@4349 a494cfbc-eb01-0410-851d-a64ba20cac60

contrib/sdk/sources/newlib/math/s_asinh.c

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+
+/* @(#)s_asinh.c 5.1 93/09/24 */
+/*
+ * ====================================================
+ * 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.
+ * ====================================================
+ */
+
+/*
+FUNCTION
+	<<asinh>>, <<asinhf>>---inverse hyperbolic sine 
+
+INDEX
+	asinh
+INDEX
+	asinhf
+
+ANSI_SYNOPSIS
+	#include <math.h>
+	double asinh(double <[x]>);
+	float asinhf(float <[x]>);
+
+TRAD_SYNOPSIS
+	#include <math.h>
+	double asinh(<[x]>)
+	double <[x]>;
+
+	float asinhf(<[x]>)
+	float <[x]>;
+
+DESCRIPTION
+<<asinh>> calculates the inverse hyperbolic sine of <[x]>.
+<<asinh>> is defined as 
+@ifnottex
+. sgn(<[x]>) * log(abs(<[x]>) + sqrt(1+<[x]>*<[x]>))
+@end ifnottex
+@tex
+$$sign(x) \times ln\Bigl(|x| + \sqrt{1+x^2}\Bigr)$$
+@end tex
+
+<<asinhf>> is identical, other than taking and returning floats.
+
+RETURNS
+<<asinh>> and <<asinhf>> return the calculated value.
+
+PORTABILITY
+Neither <<asinh>> nor <<asinhf>> are ANSI C.
+
+*/
+
+/* asinh(x)
+ * Method :
+ *	Based on 
+ *		asinh(x) = sign(x) * log [ |x| + sqrt(x*x+1) ]
+ *	we have
+ *	asinh(x) := x  if  1+x*x=1,
+ *		 := sign(x)*(log(x)+ln2)) for large |x|, else
+ *		 := sign(x)*log(2|x|+1/(|x|+sqrt(x*x+1))) if|x|>2, else
+ *		 := sign(x)*log1p(|x| + x^2/(1 + sqrt(1+x^2)))  
+ */
+
+#include "fdlibm.h"
+
+#ifndef _DOUBLE_IS_32BITS
+
+#ifdef __STDC__
+static const double 
+#else
+static double 
+#endif
+one =  1.00000000000000000000e+00, /* 0x3FF00000, 0x00000000 */
+ln2 =  6.93147180559945286227e-01, /* 0x3FE62E42, 0xFEFA39EF */
+huge=  1.00000000000000000000e+300; 
+
+#ifdef __STDC__
+	double asinh(double x)
+#else
+	double asinh(x)
+	double x;
+#endif
+{	
+	double t,w;
+	__int32_t hx,ix;
+	GET_HIGH_WORD(hx,x);
+	ix = hx&0x7fffffff;
+	if(ix>=0x7ff00000) return x+x;	/* x is inf or NaN */
+	if(ix< 0x3e300000) {	/* |x|<2**-28 */
+	    if(huge+x>one) return x;	/* return x inexact except 0 */
+	} 
+	if(ix>0x41b00000) {	/* |x| > 2**28 */
+	    w = __ieee754_log(fabs(x))+ln2;
+	} else if (ix>0x40000000) {	/* 2**28 > |x| > 2.0 */
+	    t = fabs(x);
+	    w = __ieee754_log(2.0*t+one/(__ieee754_sqrt(x*x+one)+t));
+	} else {		/* 2.0 > |x| > 2**-28 */
+	    t = x*x;
+	    w =log1p(fabs(x)+t/(one+__ieee754_sqrt(one+t)));
+	}
+	if(hx>0) return w; else return -w;
+}
+
+#endif /* _DOUBLE_IS_32BITS */