mirror of
https://github.com/adtools/clib2.git
synced 2025-12-08 14:59:05 +00:00
5ea68e3265
was within the valid range for a log() function. Using DBL_EPSILON as the threshold was not correct as EPSILON is 2.2204460492503131E-16 whereas values like 1E-200 are still valid double values for a log(). git-svn-id: file:///Users/olsen/Code/migration-svn-zu-git/logical-line-staging/clib2/trunk@15175 87f5fb63-7c3d-0410-a384-fd976d0f7a62
264 lines
6.1 KiB
C
264 lines
6.1 KiB
C
/*
|
|
* $Id: math_log.c,v 1.10 2007-11-08 11:23:53 damato Exp $
|
|
*
|
|
* :ts=4
|
|
*
|
|
* Portable ISO 'C' (1994) runtime library for the Amiga computer
|
|
* Copyright (c) 2002-2006 by Olaf Barthel <olsen (at) sourcery.han.de>
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
*
|
|
* - Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
*
|
|
* - Neither the name of Olaf Barthel nor the names of contributors
|
|
* may be used to endorse or promote products derived from this
|
|
* software without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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.
|
|
*
|
|
*
|
|
* PowerPC math library based in part on work by Sun Microsystems
|
|
* 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 _MATH_HEADERS_H
|
|
#include "math_headers.h"
|
|
#endif /* _MATH_HEADERS_H */
|
|
|
|
/****************************************************************************/
|
|
|
|
#if defined(FLOATING_POINT_SUPPORT)
|
|
|
|
/****************************************************************************/
|
|
|
|
#if defined(IEEE_FLOATING_POINT_SUPPORT)
|
|
|
|
/****************************************************************************/
|
|
|
|
#if defined(__GNUC__)
|
|
|
|
/****************************************************************************/
|
|
|
|
#if defined(SMALL_DATA)
|
|
#define A4(x) "a4@(" #x ":W)"
|
|
#elif defined(SMALL_DATA32)
|
|
#define A4(x) "a4@(" #x ":L)"
|
|
#else
|
|
#define A4(x) #x
|
|
#endif /* SMALL_DATA */
|
|
|
|
/****************************************************************************/
|
|
|
|
extern double __log(double x);
|
|
|
|
/****************************************************************************/
|
|
|
|
asm("
|
|
|
|
.text
|
|
.even
|
|
|
|
.globl _MathIeeeDoubTransBase
|
|
.globl ___log
|
|
|
|
___log:
|
|
|
|
movel a6,sp@-
|
|
movel "A4(_MathIeeeDoubTransBase)",a6
|
|
moveml sp@(8),d0/d1
|
|
jsr a6@(-84:W)
|
|
movel sp@+,a6
|
|
rts
|
|
|
|
");
|
|
|
|
/****************************************************************************/
|
|
|
|
#else
|
|
|
|
/****************************************************************************/
|
|
|
|
INLINE STATIC const double
|
|
__log(double x)
|
|
{
|
|
double result;
|
|
|
|
result = IEEEDPLog(x);
|
|
|
|
return(result);
|
|
}
|
|
|
|
/****************************************************************************/
|
|
|
|
#endif /* __GNUC__ */
|
|
|
|
/****************************************************************************/
|
|
|
|
#endif /* IEEE_FLOATING_POINT_SUPPORT */
|
|
|
|
/****************************************************************************/
|
|
|
|
#if defined(M68881_FLOATING_POINT_SUPPORT)
|
|
|
|
INLINE STATIC const double
|
|
__log(double x)
|
|
{
|
|
double result;
|
|
|
|
__asm ("flogn%.x %1,%0"
|
|
: "=f" (result)
|
|
: "f" (x));
|
|
|
|
return(result);
|
|
}
|
|
|
|
#endif /* M68881_FLOATING_POINT_SUPPORT */
|
|
|
|
/****************************************************************************/
|
|
|
|
#if defined(__PPC__)
|
|
|
|
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 */
|
|
zero = 0.0;
|
|
|
|
INLINE STATIC double
|
|
__log(double x)
|
|
{
|
|
double hfsq,f,s,z,R,w,t1,t2,dk;
|
|
int k,hx,i,j;
|
|
unsigned int 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);
|
|
}
|
|
}
|
|
|
|
#endif /* PPC_FLOATING_POINT_SUPPORT */
|
|
|
|
/****************************************************************************/
|
|
|
|
double
|
|
log(double x)
|
|
{
|
|
double result;
|
|
|
|
if(x > 0)
|
|
{
|
|
result = __log(x);
|
|
}
|
|
else
|
|
{
|
|
__set_errno(ERANGE);
|
|
|
|
result = -__inf();
|
|
}
|
|
|
|
return(result);
|
|
}
|
|
|
|
/****************************************************************************/
|
|
|
|
#endif /* FLOATING_POINT_SUPPORT */
|