diff options
Diffstat (limited to 'libm/bsdsrc/b_exp.c')
| -rw-r--r-- | libm/bsdsrc/b_exp.c | 177 |
1 files changed, 0 insertions, 177 deletions
diff --git a/libm/bsdsrc/b_exp.c b/libm/bsdsrc/b_exp.c deleted file mode 100644 index 32873b9..0000000 --- a/libm/bsdsrc/b_exp.c +++ /dev/null @@ -1,177 +0,0 @@ -/* - * 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[] = "@(#)exp.c 8.1 (Berkeley) 6/4/93"; -#endif /* not lint */ -#include <sys/cdefs.h> -/* __FBSDID("$FreeBSD: src/lib/msun/bsdsrc/b_exp.c,v 1.7 2004/12/16 20:40:37 das Exp $"); */ - - -/* EXP(X) - * RETURN THE EXPONENTIAL OF X - * 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, 2/15/85, 3/7/85, 3/24/85, 4/16/85, 6/14/86. - * - * Required system supported functions: - * scalb(x,n) - * copysign(x,y) - * finite(x) - * - * 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 exp(r) by - * - * exp(r) = 1 + r + r*R1/(2-R1), - * where - * R1 = x - x^2*(p1+x^2*(p2+x^2*(p3+x^2*(p4+p5*x^2)))). - * - * 3. exp(x) = 2^k * exp(r) . - * - * Special cases: - * exp(INF) is INF, exp(NaN) is NaN; - * exp(-INF)= 0; - * for finite argument, only exp(0)=1 is exact. - * - * Accuracy: - * exp(x) returns the exponential of x nearly rounded. In a test run - * with 1,156,000 random arguments on a VAX, the maximum observed - * error was 0.869 ulps (units in the last place). - */ - -#include "mathimpl.h" - -const static double p1 = 0x1.555555555553ep-3; -const static double p2 = -0x1.6c16c16bebd93p-9; -const static double p3 = 0x1.1566aaf25de2cp-14; -const static double p4 = -0x1.bbd41c5d26bf1p-20; -const static double p5 = 0x1.6376972bea4d0p-25; -const static double ln2hi = 0x1.62e42fee00000p-1; -const static double ln2lo = 0x1.a39ef35793c76p-33; -const static double lnhuge = 0x1.6602b15b7ecf2p9; -const static double lntiny = -0x1.77af8ebeae354p9; -const static double invln2 = 0x1.71547652b82fep0; - -#if 0 -double exp(x) -double x; -{ - double z,hi,lo,c; - int k; - -#if !defined(vax)&&!defined(tahoe) - if(x!=x) return(x); /* x is NaN */ -#endif /* !defined(vax)&&!defined(tahoe) */ - if( x <= lnhuge ) { - if( x >= lntiny ) { - - /* argument reduction : x --> x - k*ln2 */ - - k=invln2*x+copysign(0.5,x); /* k=NINT(x/ln2) */ - - /* express x-k*ln2 as hi-lo and let x=hi-lo rounded */ - - hi=x-k*ln2hi; - x=hi-(lo=k*ln2lo); - - /* return 2^k*[1+x+x*c/(2+c)] */ - z=x*x; - c= x - z*(p1+z*(p2+z*(p3+z*(p4+z*p5)))); - return scalb(1.0+(hi-(lo-(x*c)/(2.0-c))),k); - - } - /* end of x > lntiny */ - - else - /* exp(-big#) underflows to zero */ - if(finite(x)) return(scalb(1.0,-5000)); - - /* exp(-INF) is zero */ - else return(0.0); - } - /* end of x < lnhuge */ - - else - /* exp(INF) is INF, exp(+big#) overflows to INF */ - return( finite(x) ? scalb(1.0,5000) : x); -} -#endif - -/* returns exp(r = x + c) for |c| < |x| with no overlap. */ - -double __exp__D(x, c) -double x, c; -{ - double z,hi,lo; - int k; - - if (x != x) /* x is NaN */ - return(x); - if ( x <= lnhuge ) { - if ( x >= lntiny ) { - - /* argument reduction : x --> x - k*ln2 */ - z = invln2*x; - k = z + copysign(.5, x); - - /* express (x+c)-k*ln2 as hi-lo and let x=hi-lo rounded */ - - hi=(x-k*ln2hi); /* Exact. */ - x= hi - (lo = k*ln2lo-c); - /* return 2^k*[1+x+x*c/(2+c)] */ - z=x*x; - c= x - z*(p1+z*(p2+z*(p3+z*(p4+z*p5)))); - c = (x*c)/(2.0-c); - - return scalb(1.+(hi-(lo - c)), k); - } - /* end of x > lntiny */ - - else - /* exp(-big#) underflows to zero */ - if(finite(x)) return(scalb(1.0,-5000)); - - /* exp(-INF) is zero */ - else return(0.0); - } - /* end of x < lnhuge */ - - else - /* exp(INF) is INF, exp(+big#) overflows to INF */ - return( finite(x) ? scalb(1.0,5000) : x); -} |