diff options
Diffstat (limited to 'sysdeps/generic/pow.c')
| -rw-r--r-- | sysdeps/generic/pow.c | 215 |
1 files changed, 0 insertions, 215 deletions
diff --git a/sysdeps/generic/pow.c b/sysdeps/generic/pow.c deleted file mode 100644 index 5121f30464..0000000000 --- a/sysdeps/generic/pow.c +++ /dev/null @@ -1,215 +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[] = "@(#)pow.c 8.1 (Berkeley) 6/4/93"; -#endif /* not lint */ - -/* POW(X,Y) - * RETURN X**Y - * DOUBLE PRECISION (VAX D format 56 bits, IEEE DOUBLE 53 BITS) - * CODED IN C BY K.C. NG, 1/8/85; - * REVISED BY K.C. NG on 7/10/85. - * KERNEL pow_P() REPLACED BY P. McILROY 7/22/92. - * Required system supported functions: - * scalb(x,n) - * logb(x) - * copysign(x,y) - * finite(x) - * drem(x,y) - * - * Required kernel functions: - * exp__D(a,c) exp(a + c) for |a| << |c| - * struct d_double dlog(x) r.a + r.b, |r.b| < |r.a| - * - * Method - * 1. Compute and return log(x) in three pieces: - * log(x) = n*ln2 + hi + lo, - * where n is an integer. - * 2. Perform y*log(x) by simulating muti-precision arithmetic and - * return the answer in three pieces: - * y*log(x) = m*ln2 + hi + lo, - * where m is an integer. - * 3. Return x**y = exp(y*log(x)) - * = 2^m * ( exp(hi+lo) ). - * - * Special cases: - * (anything) ** 0 is 1 ; - * (anything) ** 1 is itself; - * (anything) ** NaN is NaN; - * NaN ** (anything except 0) is NaN; - * +(anything > 1) ** +INF is +INF; - * -(anything > 1) ** +INF is NaN; - * +-(anything > 1) ** -INF is +0; - * +-(anything < 1) ** +INF is +0; - * +(anything < 1) ** -INF is +INF; - * -(anything < 1) ** -INF is NaN; - * +-1 ** +-INF is NaN and signal INVALID; - * +0 ** +(anything except 0, NaN) is +0; - * -0 ** +(anything except 0, NaN, odd integer) is +0; - * +0 ** -(anything except 0, NaN) is +INF and signal DIV-BY-ZERO; - * -0 ** -(anything except 0, NaN, odd integer) is +INF with signal; - * -0 ** (odd integer) = -( +0 ** (odd integer) ); - * +INF ** +(anything except 0,NaN) is +INF; - * +INF ** -(anything except 0,NaN) is +0; - * -INF ** (odd integer) = -( +INF ** (odd integer) ); - * -INF ** (even integer) = ( +INF ** (even integer) ); - * -INF ** -(anything except integer,NaN) is NaN with signal; - * -(x=anything) ** (k=integer) is (-1)**k * (x ** k); - * -(anything except 0) ** (non-integer) is NaN with signal; - * - * Accuracy: - * pow(x,y) returns x**y nearly rounded. In particular, on a SUN, a VAX, - * and a Zilog Z8000, - * pow(integer,integer) - * always returns the correct integer provided it is representable. - * In a test run with 100,000 random arguments with 0 < x, y < 20.0 - * on a VAX, the maximum observed error was 1.79 ulps (units in 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 <errno.h> -#include <math.h> - -#include "mathimpl.h" - -#if (defined(vax) || defined(tahoe)) -#define TRUNC(x) x = (double) (float) x -#define _IEEE 0 -#else -#define _IEEE 1 -#define endian (((*(int *) &one)) ? 1 : 0) -#define TRUNC(x) *(((int *) &x)+endian) &= 0xf8000000 -#define infnan(x) 0.0 -#endif /* vax or tahoe */ - -const static double zero=0.0, one=1.0, two=2.0, negone= -1.0; - -static double pow_P __P((double, double)); - -double pow(x,y) -double x,y; -{ - double t; - if (y==zero) - return (one); - else if (y==one || (_IEEE && x != x)) - return (x); /* if x is NaN or y=1 */ - else if (_IEEE && y!=y) /* if y is NaN */ - return (y); - else if (!finite(y)) /* if y is INF */ - if ((t=fabs(x))==one) /* +-1 ** +-INF is NaN */ - return (y - y); - else if (t>one) - return ((y<0)? zero : ((x<zero)? y-y : y)); - else - return ((y>0)? zero : ((x<0)? y-y : -y)); - else if (y==two) - return (x*x); - else if (y==negone) - return (one/x); - /* x > 0, x == +0 */ - else if (copysign(one, x) == one) - return (pow_P(x, y)); - - /* sign(x)= -1 */ - /* if y is an even integer */ - else if ( (t=drem(y,two)) == zero) - return (pow_P(-x, y)); - - /* if y is an odd integer */ - else if (copysign(t,one) == one) - return (-pow_P(-x, y)); - - /* Henceforth y is not an integer */ - else if (x==zero) /* x is -0 */ - return ((y>zero)? -x : one/(-x)); - else if (_IEEE) - return (zero/zero); - else - return (infnan(EDOM)); -} -/* kernel function for x >= 0 */ -static double -#ifdef _ANSI_SOURCE -pow_P(double x, double y) -#else -pow_P(x, y) double x, y; -#endif -{ - struct Double s, t, __log__D(); - double __exp__D(), huge = 1e300, tiny = 1e-300; - - if (x == zero) - if (y > zero) - return (zero); - else if (_IEEE) - return (huge*huge); - else - return (infnan(ERANGE)); - if (x == one) - return (one); - if (!finite(x)) - if (y < zero) - return (zero); - else if (_IEEE) - return (huge*huge); - else - return (infnan(ERANGE)); - if (y >= 7e18) /* infinity */ - if (x < 1) - return(tiny*tiny); - else if (_IEEE) - return (huge*huge); - else - return (infnan(ERANGE)); - - /* Return exp(y*log(x)), using simulated extended */ - /* precision for the log and the multiply. */ - - s = __log__D(x); - t.a = y; - TRUNC(t.a); - t.b = y - t.a; - t.b = s.b*y + t.b*s.a; - t.a *= s.a; - s.a = t.a + t.b; - s.b = (t.a - s.a) + t.b; - return (__exp__D(s.a, s.b)); -} |