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Diffstat (limited to 'sysdeps/generic/exp.c')
| -rw-r--r-- | sysdeps/generic/exp.c | 203 |
1 files changed, 0 insertions, 203 deletions
diff --git a/sysdeps/generic/exp.c b/sysdeps/generic/exp.c deleted file mode 100644 index 9b4f045f82..0000000000 --- a/sysdeps/generic/exp.c +++ /dev/null @@ -1,203 +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 */ - -/* 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). - * - * 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(lntiny,-9.5654310917272452386E1 ,4f01,c3bf,33af,d72e, 7,-.BF4F01D72E33AF) -vc(invln2, 1.4426950408889634148E0 ,aa3b,40b8,17f1,295c, 1, .B8AA3B295C17F1) -vc(p1, 1.6666666666666602251E-1 ,aaaa,3f2a,a9f1,aaaa, -2, .AAAAAAAAAAA9F1) -vc(p2, -2.7777777777015591216E-3 ,0b60,bc36,ec94,b5f5, -8,-.B60B60B5F5EC94) -vc(p3, 6.6137563214379341918E-5 ,b355,398a,f15f,792e, -13, .8AB355792EF15F) -vc(p4, -1.6533902205465250480E-6 ,ea0e,b6dd,5f84,2e93, -19,-.DDEA0E2E935F84) -vc(p5, 4.1381367970572387085E-8 ,bb4b,3431,2683,95f5, -24, .B1BB4B95F52683) - -#ifdef vccast -#define ln2hi vccast(ln2hi) -#define ln2lo vccast(ln2lo) -#define lnhuge vccast(lnhuge) -#define lntiny vccast(lntiny) -#define invln2 vccast(invln2) -#define p1 vccast(p1) -#define p2 vccast(p2) -#define p3 vccast(p3) -#define p4 vccast(p4) -#define p5 vccast(p5) -#endif - -ic(p1, 1.6666666666666601904E-1, -3, 1.555555555553E) -ic(p2, -2.7777777777015593384E-3, -9, -1.6C16C16BEBD93) -ic(p3, 6.6137563214379343612E-5, -14, 1.1566AAF25DE2C) -ic(p4, -1.6533902205465251539E-6, -20, -1.BBD41C5D26BF1) -ic(p5, 4.1381367970572384604E-8, -25, 1.6376972BEA4D0) -ic(ln2hi, 6.9314718036912381649E-1, -1, 1.62E42FEE00000) -ic(ln2lo, 1.9082149292705877000E-10,-33, 1.A39EF35793C76) -ic(lnhuge, 7.1602103751842355450E2, 9, 1.6602B15B7ECF2) -ic(lntiny,-7.5137154372698068983E2, 9, -1.77AF8EBEAE354) -ic(invln2, 1.4426950408889633870E0, 0, 1.71547652B82FE) - -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); -} - -/* returns exp(r = x + c) for |c| < |x| with no overlap. */ - -double __exp__D(x, c) -double x, c; -{ - double z,hi,lo, t; - 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 */ - 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); -} |