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Diffstat (limited to 'sysdeps/ieee754/cbrt.c')
| -rw-r--r-- | sysdeps/ieee754/cbrt.c | 120 |
1 files changed, 0 insertions, 120 deletions
diff --git a/sysdeps/ieee754/cbrt.c b/sysdeps/ieee754/cbrt.c deleted file mode 100644 index fe5fb95511..0000000000 --- a/sysdeps/ieee754/cbrt.c +++ /dev/null @@ -1,120 +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[] = "@(#)cbrt.c 8.1 (Berkeley) 6/4/93"; -#endif /* not lint */ - -#include <sys/cdefs.h> - -/* kahan's cube root (53 bits IEEE double precision) - * for IEEE machines only - * coded in C by K.C. Ng, 4/30/85 - * - * Accuracy: - * better than 0.667 ulps according to an error analysis. Maximum - * error observed was 0.666 ulps in an 1,000,000 random arguments test. - * - * Warning: this code is semi machine dependent; the ordering of words in - * a floating point number must be known in advance. I assume that the - * long interger at the address of a floating point number will be the - * leading 32 bits of that floating point number (i.e., sign, exponent, - * and the 20 most significant bits). - * On a National machine, it has different ordering; therefore, this code - * must be compiled with flag -DNATIONAL. - */ -#if !defined(vax)&&!defined(tahoe) - -static const unsigned long - B1 = 715094163, /* B1 = (682-0.03306235651)*2**20 */ - B2 = 696219795; /* B2 = (664-0.03306235651)*2**20 */ -static const double - C= 19./35., - D= -864./1225., - E= 99./70., - F= 45./28., - G= 5./14.; - -double cbrt(x) -double x; -{ - double r,s,t=0.0,w; - unsigned long *px = (unsigned long *) &x, - *pt = (unsigned long *) &t, - mexp,sign; - -#ifdef national /* ordering of words in a floating points number */ - const int n0=1,n1=0; -#else /* national */ - const int n0=0,n1=1; -#endif /* national */ - - mexp=px[n0]&0x7ff00000; - if(mexp==0x7ff00000) return(x); /* cbrt(NaN,INF) is itself */ - if(x==0.0) return(x); /* cbrt(0) is itself */ - - sign=px[n0]&0x80000000; /* sign= sign(x) */ - px[n0] ^= sign; /* x=|x| */ - - - /* rough cbrt to 5 bits */ - if(mexp==0) /* subnormal number */ - {pt[n0]=0x43500000; /* set t= 2**54 */ - t*=x; pt[n0]=pt[n0]/3+B2; - } - else - pt[n0]=px[n0]/3+B1; - - - /* new cbrt to 23 bits, may be implemented in single precision */ - r=t*t/x; - s=C+r*t; - t*=G+F/(s+E+D/s); - - /* chopped to 20 bits and make it larger than cbrt(x) */ - pt[n1]=0; pt[n0]+=0x00000001; - - - /* one step newton iteration to 53 bits with error less than 0.667 ulps */ - s=t*t; /* t*t is exact */ - r=x/s; - w=t+t; - r=(r-t)/(w+r); /* r-t is exact */ - t=t+t*r; - - - /* retore the sign bit */ - pt[n0] |= sign; - return(t); -} -#endif |