summaryrefslogtreecommitdiff
path: root/StdLib/LibC/Math/e_log2.c
diff options
context:
space:
mode:
Diffstat (limited to 'StdLib/LibC/Math/e_log2.c')
-rw-r--r--StdLib/LibC/Math/e_log2.c85
1 files changed, 0 insertions, 85 deletions
diff --git a/StdLib/LibC/Math/e_log2.c b/StdLib/LibC/Math/e_log2.c
deleted file mode 100644
index 5d15cd3b01..0000000000
--- a/StdLib/LibC/Math/e_log2.c
+++ /dev/null
@@ -1,85 +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.
- * ====================================================
- */
-#include <LibConfig.h>
-#include <sys/EfiCdefs.h>
-#if defined(LIBM_SCCS) && !defined(lint)
-__RCSID("$NetBSD: e_log2.c,v 1.1 2005/07/21 12:55:58 christos Exp $");
-#endif
-
-#include "math.h"
-#include "math_private.h"
-
-#if defined(_MSC_VER) /* Handle Microsoft VC++ compiler specifics. */
- // potential divide by 0 -- near line 53, (x-x)/zero is on purpose
- #pragma warning ( disable : 4723 )
-#endif
-
-static const double
-ln2 = 0.6931471805599452862268,
-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
-__ieee754_log2(double x)
-{
- double hfsq,f,s,z,R,w,t1,t2,dk;
- int32_t k,hx,i,j;
- u_int32_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;
- dk = (double)k;
- if((0x000fffff&(2+hx))<3) { /* |f| < 2**-20 */
- if (f==zero)
- return (dk);
- R = f*f*(0.5-0.33333333333333333*f);
- return (dk-(R-f)/ln2);
- }
- s = f/(2.0+f);
- 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;
- return (dk-(hfsq-s*(hfsq+R)-f)/ln2);
- } else
- return (dk-((s*(f-R))-f)/ln2);
-}