initial import

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diff --git a/sysdeps/generic/expm1.c b/sysdeps/generic/expm1.c
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+/*
+ * Copyright (c) 1985, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+static char sccsid[] = "@(#)expm1.c	8.1 (Berkeley) 6/4/93";
+#endif /* not lint */
+
+/* EXPM1(X)
+ * RETURN THE EXPONENTIAL OF X MINUS ONE
+ * DOUBLE PRECISION (IEEE 53 BITS, VAX D FORMAT 56 BITS)
+ * CODED IN C BY K.C. NG, 1/19/85; 
+ * REVISED BY K.C. NG on 2/6/85, 3/7/85, 3/21/85, 4/16/85.
+ *
+ * Required system supported functions:
+ *	scalb(x,n)	
+ *	copysign(x,y)	
+ *	finite(x)
+ *
+ * Kernel function:
+ *	exp__E(x,c)
+ *
+ * Method:
+ *	1. Argument Reduction: given the input x, find r and integer k such 
+ *	   that
+ *	                   x = k*ln2 + r,  |r| <= 0.5*ln2 .  
+ *	   r will be represented as r := z+c for better accuracy.
+ *
+ *	2. Compute EXPM1(r)=exp(r)-1 by 
+ *
+ *			EXPM1(r=z+c) := z + exp__E(z,c)
+ *
+ *	3. EXPM1(x) =  2^k * ( EXPM1(r) + 1-2^-k ).
+ *
+ * 	Remarks: 
+ *	   1. When k=1 and z < -0.25, we use the following formula for
+ *	      better accuracy:
+ *			EXPM1(x) = 2 * ( (z+0.5) + exp__E(z,c) )
+ *	   2. To avoid rounding error in 1-2^-k where k is large, we use
+ *			EXPM1(x) = 2^k * { [z+(exp__E(z,c)-2^-k )] + 1 }
+ *	      when k>56. 
+ *
+ * Special cases:
+ *	EXPM1(INF) is INF, EXPM1(NaN) is NaN;
+ *	EXPM1(-INF)= -1;
+ *	for finite argument, only EXPM1(0)=0 is exact.
+ *
+ * Accuracy:
+ *	EXPM1(x) returns the exact (exp(x)-1) nearly rounded. In a test run with
+ *	1,166,000 random arguments on a VAX, the maximum observed error was
+ *	.872 ulps (units of the last place).
+ *
+ * Constants:
+ * The hexadecimal values are the intended ones for the following constants.
+ * The decimal values may be used, provided that the compiler will convert
+ * from decimal to binary accurately enough to produce the hexadecimal values
+ * shown.
+ */
+
+#include "mathimpl.h"
+
+vc(ln2hi,  6.9314718055829871446E-1  ,7217,4031,0000,f7d0,   0, .B17217F7D00000)
+vc(ln2lo,  1.6465949582897081279E-12 ,bcd5,2ce7,d9cc,e4f1, -39, .E7BCD5E4F1D9CC)
+vc(lnhuge, 9.4961163736712506989E1   ,ec1d,43bd,9010,a73e,   7, .BDEC1DA73E9010)
+vc(invln2, 1.4426950408889634148E0   ,aa3b,40b8,17f1,295c,   1, .B8AA3B295C17F1)
+
+ic(ln2hi,  6.9314718036912381649E-1,   -1, 1.62E42FEE00000)
+ic(ln2lo,  1.9082149292705877000E-10, -33, 1.A39EF35793C76)
+ic(lnhuge, 7.1602103751842355450E2,     9, 1.6602B15B7ECF2)
+ic(invln2, 1.4426950408889633870E0,     0, 1.71547652B82FE)
+
+#ifdef vccast
+#define	ln2hi	vccast(ln2hi)
+#define	ln2lo	vccast(ln2lo)
+#define	lnhuge	vccast(lnhuge)
+#define	invln2	vccast(invln2)
+#endif
+
+double expm1(x)
+double x;
+{
+	const static double one=1.0, half=1.0/2.0; 
+	double  z,hi,lo,c;
+	int k;
+#if defined(vax)||defined(tahoe)
+	static prec=56;
+#else	/* defined(vax)||defined(tahoe) */
+	static prec=53;
+#endif	/* defined(vax)||defined(tahoe) */
+
+#if !defined(vax)&&!defined(tahoe)
+	if(x!=x) return(x);	/* x is NaN */
+#endif	/* !defined(vax)&&!defined(tahoe) */
+
+	if( x <= lnhuge ) {
+		if( x >= -40.0 ) {
+
+		    /* argument reduction : x - k*ln2 */
+			k= invln2 *x+copysign(0.5,x);	/* k=NINT(x/ln2) */
+			hi=x-k*ln2hi ; 
+			z=hi-(lo=k*ln2lo);
+			c=(hi-z)-lo;
+
+			if(k==0) return(z+__exp__E(z,c));
+			if(k==1)
+			    if(z< -0.25) 
+				{x=z+half;x +=__exp__E(z,c); return(x+x);}
+			    else
+				{z+=__exp__E(z,c); x=half+z; return(x+x);}
+		    /* end of k=1 */
+
+			else {
+			    if(k<=prec)
+			      { x=one-scalb(one,-k); z += __exp__E(z,c);}
+			    else if(k<100)
+			      { x = __exp__E(z,c)-scalb(one,-k); x+=z; z=one;}
+			    else 
+			      { x = __exp__E(z,c)+z; z=one;}
+
+			    return (scalb(x+z,k));  
+			}
+		}
+		/* end of x > lnunfl */
+
+		else 
+		     /* expm1(-big#) rounded to -1 (inexact) */
+		     if(finite(x))  
+			 { ln2hi+ln2lo; return(-one);}
+
+		     /* expm1(-INF) is -1 */
+		     else return(-one);
+	}
+	/* end of x < lnhuge */
+
+	else 
+	/*  expm1(INF) is INF, expm1(+big#) overflows to INF */
+	    return( finite(x) ?  scalb(one,5000) : x);
+}
+
+weak_alias (__expm1, expm1)