diff options
Diffstat (limited to 'libm/src/e_logf.c')
-rw-r--r-- | libm/src/e_logf.c | 83 |
1 files changed, 0 insertions, 83 deletions
diff --git a/libm/src/e_logf.c b/libm/src/e_logf.c deleted file mode 100644 index 7cee2ab..0000000 --- a/libm/src/e_logf.c +++ /dev/null @@ -1,83 +0,0 @@ -/* e_logf.c -- float version of e_log.c. - * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. - */ - -/* - * ==================================================== - * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. - * - * Developed at SunPro, a Sun Microsystems, Inc. business. - * Permission to use, copy, modify, and distribute this - * software is freely granted, provided that this notice - * is preserved. - * ==================================================== - */ - -#ifndef lint -static char rcsid[] = "$FreeBSD: src/lib/msun/src/e_logf.c,v 1.8 2005/11/12 18:20:09 bde Exp $"; -#endif - -#include "math.h" -#include "math_private.h" - -static const float -ln2_hi = 6.9313812256e-01, /* 0x3f317180 */ -ln2_lo = 9.0580006145e-06, /* 0x3717f7d1 */ -two25 = 3.355443200e+07, /* 0x4c000000 */ -/* |(log(1+s)-log(1-s))/s - Lg(s)| < 2**-34.24 (~[-4.95e-11, 4.97e-11]). */ -Lg1 = 0xaaaaaa.0p-24, /* 0.66666662693 */ -Lg2 = 0xccce13.0p-25, /* 0.40000972152 */ -Lg3 = 0x91e9ee.0p-25, /* 0.28498786688 */ -Lg4 = 0xf89e26.0p-26; /* 0.24279078841 */ - -static const float zero = 0.0; - -float -__ieee754_logf(float x) -{ - float hfsq,f,s,z,R,w,t1,t2,dk; - int32_t k,ix,i,j; - - GET_FLOAT_WORD(ix,x); - - k=0; - if (ix < 0x00800000) { /* x < 2**-126 */ - if ((ix&0x7fffffff)==0) - return -two25/zero; /* log(+-0)=-inf */ - if (ix<0) return (x-x)/zero; /* log(-#) = NaN */ - k -= 25; x *= two25; /* subnormal number, scale up x */ - GET_FLOAT_WORD(ix,x); - } - if (ix >= 0x7f800000) return x+x; - k += (ix>>23)-127; - ix &= 0x007fffff; - i = (ix+(0x95f64<<3))&0x800000; - SET_FLOAT_WORD(x,ix|(i^0x3f800000)); /* normalize x or x/2 */ - k += (i>>23); - f = x-(float)1.0; - if((0x007fffff&(15+ix))<16) { /* |f| < 2**-20 */ - if(f==zero) if(k==0) return zero; else {dk=(float)k; - return dk*ln2_hi+dk*ln2_lo;} - R = f*f*((float)0.5-(float)0.33333333333333333*f); - if(k==0) return f-R; else {dk=(float)k; - return dk*ln2_hi-((R-dk*ln2_lo)-f);} - } - s = f/((float)2.0+f); - dk = (float)k; - z = s*s; - i = ix-(0x6147a<<3); - w = z*z; - j = (0x6b851<<3)-ix; - t1= w*(Lg2+w*Lg4); - t2= z*(Lg1+w*Lg3); - i |= j; - R = t2+t1; - if(i>0) { - hfsq=(float)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); - } -} |