X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Fmath%2Fe_log.c;fp=src%2Fmath%2Fe_log.c;h=0000000000000000000000000000000000000000;hb=b69f695acedd4ce2798ef9ea28d834ceccc789bd;hp=9eb0e4448064c05be3e8f16c20e5dfc095ed1ce4;hpb=d46cf2e14cc4df7cc75e77d7009fcb6df1f48a33;p=musl

diff --git a/src/math/e_log.c b/src/math/e_log.c
deleted file mode 100644
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--- a/src/math/e_log.c
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@@ -1,131 +0,0 @@
-
-/* @(#)e_log.c 1.3 95/01/18 */
-/*
- * ====================================================
- * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
- *
- * Developed at SunSoft, a Sun Microsystems, Inc. business.
- * Permission to use, copy, modify, and distribute this
- * software is freely granted, provided that this notice 
- * is preserved.
- * ====================================================
- */
-
-/* log(x)
- * Return the logrithm of x
- *
- * Method :                  
- *   1. Argument Reduction: find k and f such that 
- *                      x = 2^k * (1+f), 
- *         where  sqrt(2)/2 < 1+f < sqrt(2) .
- *
- *   2. Approximation of log(1+f).
- *      Let s = f/(2+f) ; based on log(1+f) = log(1+s) - log(1-s)
- *               = 2s + 2/3 s**3 + 2/5 s**5 + .....,
- *               = 2s + s*R
- *      We use a special Reme algorithm on [0,0.1716] to generate 
- *      a polynomial of degree 14 to approximate R The maximum error 
- *      of this polynomial approximation is bounded by 2**-58.45. In
- *      other words,
- *                      2      4      6      8      10      12      14
- *          R(z) ~ Lg1*s +Lg2*s +Lg3*s +Lg4*s +Lg5*s  +Lg6*s  +Lg7*s
- *      (the values of Lg1 to Lg7 are listed in the program)
- *      and
- *          |      2          14          |     -58.45
- *          | Lg1*s +...+Lg7*s    -  R(z) | <= 2 
- *          |                             |
- *      Note that 2s = f - s*f = f - hfsq + s*hfsq, where hfsq = f*f/2.
- *      In order to guarantee error in log below 1ulp, we compute log
- *      by
- *              log(1+f) = f - s*(f - R)        (if f is not too large)
- *              log(1+f) = f - (hfsq - s*(hfsq+R)).     (better accuracy)
- *      
- *      3. Finally,  log(x) = k*ln2 + log(1+f).  
- *                          = k*ln2_hi+(f-(hfsq-(s*(hfsq+R)+k*ln2_lo)))
- *         Here ln2 is split into two floating point number: 
- *                      ln2_hi + ln2_lo,
- *         where n*ln2_hi is always exact for |n| < 2000.
- *
- * Special cases:
- *      log(x) is NaN with signal if x < 0 (including -INF) ; 
- *      log(+INF) is +INF; log(0) is -INF with signal;
- *      log(NaN) is that NaN with no signal.
- *
- * Accuracy:
- *      according to an error analysis, the error is always less than
- *      1 ulp (unit 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 <math.h>
-#include "math_private.h"
-
-static const double
-ln2_hi  =  6.93147180369123816490e-01,  /* 3fe62e42 fee00000 */
-ln2_lo  =  1.90821492927058770002e-10,  /* 3dea39ef 35793c76 */
-two54   =  1.80143985094819840000e+16,  /* 43500000 00000000 */
-Lg1 = 6.666666666666735130e-01,  /* 3FE55555 55555593 */
-Lg2 = 3.999999999940941908e-01,  /* 3FD99999 9997FA04 */
-Lg3 = 2.857142874366239149e-01,  /* 3FD24924 94229359 */
-Lg4 = 2.222219843214978396e-01,  /* 3FCC71C5 1D8E78AF */
-Lg5 = 1.818357216161805012e-01,  /* 3FC74664 96CB03DE */
-Lg6 = 1.531383769920937332e-01,  /* 3FC39A09 D078C69F */
-Lg7 = 1.479819860511658591e-01;  /* 3FC2F112 DF3E5244 */
-
-static const double zero   =  0.0;
-
-double
-log(double x)
-{
-        double hfsq,f,s,z,R,w,t1,t2,dk;
-        int32_t k,hx,i,j;
-        uint32_t lx;
-
-        EXTRACT_WORDS(hx,lx,x);
-
-        k=0;
-        if (hx < 0x00100000) {                  /* x < 2**-1022  */
-            if (((hx&0x7fffffff)|lx)==0) 
-                return -two54/zero;             /* log(+-0)=-inf */
-            if (hx<0) return (x-x)/zero;        /* log(-#) = NaN */
-            k -= 54; x *= two54; /* subnormal number, scale up x */
-            GET_HIGH_WORD(hx,x);
-        } 
-        if (hx >= 0x7ff00000) return x+x;
-        k += (hx>>20)-1023;
-        hx &= 0x000fffff;
-        i = (hx+0x95f64)&0x100000;
-        SET_HIGH_WORD(x,hx|(i^0x3ff00000));     /* normalize x or x/2 */
-        k += (i>>20);
-        f = x-1.0;
-        if((0x000fffff&(2+hx))<3) {     /* |f| < 2**-20 */
-            if(f==zero) { if(k==0) return zero;  else {dk=(double)k;
-                                 return dk*ln2_hi+dk*ln2_lo;} }
-            R = f*f*(0.5-0.33333333333333333*f);
-            if(k==0) return f-R; else {dk=(double)k;
-                     return dk*ln2_hi-((R-dk*ln2_lo)-f);}
-        }
-        s = f/(2.0+f); 
-        dk = (double)k;
-        z = s*s;
-        i = hx-0x6147a;
-        w = z*z;
-        j = 0x6b851-hx;
-        t1= w*(Lg2+w*(Lg4+w*Lg6)); 
-        t2= z*(Lg1+w*(Lg3+w*(Lg5+w*Lg7))); 
-        i |= j;
-        R = t2+t1;
-        if(i>0) {
-            hfsq=0.5*f*f;
-            if(k==0) return f-(hfsq-s*(hfsq+R)); else
-                     return dk*ln2_hi-((hfsq-(s*(hfsq+R)+dk*ln2_lo))-f);
-        } else {
-            if(k==0) return f-s*(f-R); else
-                     return dk*ln2_hi-((s*(f-R)-dk*ln2_lo)-f);
-        }
-}