mirror of
https://github.com/opnsense/src.git
synced 2026-02-26 11:20:29 -05:00
7dbbb6dde3
are workarounds for various symptoms of the problem described in clang bugs 3929, 8100, 8241, 10409, and 12958. The regression tests did their job: they failed, someone brought it up on the mailing lists, and then the issue got ignored for 6 months. Oops. There may still be some regressions for functions we don't have test coverage for yet.
89 lines
2.4 KiB
C
89 lines
2.4 KiB
C
/* 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.
|
|
* ====================================================
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#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;
|
|
static volatile float vzero = 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/vzero; /* 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&(0x8000+ix))<0xc000) { /* -2**-9 <= f < 2**-9 */
|
|
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);
|
|
}
|
|
}
|