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git-svn-id: file:///Users/olsen/Code/migration-svn-zu-git/logical-line-staging/clib2/trunk@14731 87f5fb63-7c3d-0410-a384-fd976d0f7a62
268 lines
6.3 KiB
C
268 lines
6.3 KiB
C
/*
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* $Id: math_log.c,v 1.2 2004-09-27 15:06:19 tfrieden Exp $
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*
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* :ts=4
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*
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* Portable ISO 'C' (1994) runtime library for the Amiga computer
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* Copyright (c) 2002-2004 by Olaf Barthel <olsen@sourcery.han.de>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* - Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* - Neither the name of Olaf Barthel nor the names of contributors
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* may be used to endorse or promote products derived from this
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* software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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*
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* PowerPC math library based in part on work by Sun Microsystems
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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*/
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#ifndef _MATH_HEADERS_H
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#include "math_headers.h"
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#endif /* _MATH_HEADERS_H */
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/****************************************************************************/
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#if defined(FLOATING_POINT_SUPPORT)
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/****************************************************************************/
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#if defined(IEEE_FLOATING_POINT_SUPPORT)
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/****************************************************************************/
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#if defined(__GNUC__)
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/****************************************************************************/
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#if defined(SMALL_DATA)
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#define A4(x) "a4@(" #x ":W)"
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#elif defined(SMALL_DATA32)
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#define A4(x) "a4@(" #x ":L)"
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#else
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#define A4(x) #x
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#endif /* SMALL_DATA */
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/****************************************************************************/
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extern double __log(double x);
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/****************************************************************************/
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asm("
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.text
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.even
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.globl _MathIeeeDoubTransBase
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.globl ___log
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___log:
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movel a6,sp@-
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movel "A4(_MathIeeeDoubTransBase)",a6
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moveml sp@(8),d0/d1
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jsr a6@(-84:W)
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movel sp@+,a6
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rts
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");
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/****************************************************************************/
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#else
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/****************************************************************************/
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INLINE static const double
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__log(double x)
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{
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double result;
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result = IEEEDPLog(x);
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return(result);
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}
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/****************************************************************************/
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#endif /* __GNUC__ */
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/****************************************************************************/
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#endif /* IEEE_FLOATING_POINT_SUPPORT */
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/****************************************************************************/
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#if defined(M68881_FLOATING_POINT_SUPPORT)
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INLINE static const double
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__log(double x)
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{
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double result;
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__asm ("flogn%.x %1,%0"
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: "=f" (result)
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: "f" (x));
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return(result);
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}
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#endif /* M68881_FLOATING_POINT_SUPPORT */
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/****************************************************************************/
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#if defined(__PPC__)
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static const double
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ln2_hi = 6.93147180369123816490e-01, /* 3fe62e42 fee00000 */
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ln2_lo = 1.90821492927058770002e-10, /* 3dea39ef 35793c76 */
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two54 = 1.80143985094819840000e+16, /* 43500000 00000000 */
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Lg1 = 6.666666666666735130e-01, /* 3FE55555 55555593 */
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Lg2 = 3.999999999940941908e-01, /* 3FD99999 9997FA04 */
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Lg3 = 2.857142874366239149e-01, /* 3FD24924 94229359 */
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Lg4 = 2.222219843214978396e-01, /* 3FCC71C5 1D8E78AF */
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Lg5 = 1.818357216161805012e-01, /* 3FC74664 96CB03DE */
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Lg6 = 1.531383769920937332e-01, /* 3FC39A09 D078C69F */
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Lg7 = 1.479819860511658591e-01, /* 3FC2F112 DF3E5244 */
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zero = 0.0;
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INLINE static const double
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__log(double x)
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{
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double hfsq,f,s,z,R,w,t1,t2,dk;
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int k,hx,i,j;
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unsigned int lx;
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EXTRACT_WORDS(hx,lx,x);
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k=0;
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if (hx < 0x00100000) /* x < 2**-1022 */
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{
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if (((hx&0x7fffffff)|lx)==0)
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return -two54/zero; /* log(+-0)=-inf */
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if (hx<0)
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return (x-x)/zero; /* log(-#) = NaN */
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k -= 54;
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x *= two54; /* subnormal number, scale up x */
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GET_HIGH_WORD(hx,x);
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}
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if (hx >= 0x7ff00000)
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return x+x;
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k += (hx>>20)-1023;
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hx &= 0x000fffff;
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i = (hx+0x95f64)&0x100000;
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SET_HIGH_WORD(x,hx|(i^0x3ff00000)); /* normalize x or x/2 */
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k += (i>>20);
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f = x-1.0;
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if((0x000fffff&(2+hx))<3) /* |f| < 2**-20 */
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{
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if(f==zero)
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{
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if(k==0)
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return zero;
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else
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{
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dk=(double)k;
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return dk*ln2_hi+dk*ln2_lo;
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}
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}
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R = f*f*(0.5-0.33333333333333333*f);
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if(k==0)
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return f-R;
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else
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{
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dk=(double)k;
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return dk*ln2_hi-((R-dk*ln2_lo)-f);
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}
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}
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s = f/(2.0+f);
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dk = (double)k;
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z = s*s;
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i = hx-0x6147a;
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w = z*z;
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j = 0x6b851-hx;
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t1= w*(Lg2+w*(Lg4+w*Lg6));
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t2= z*(Lg1+w*(Lg3+w*(Lg5+w*Lg7)));
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i |= j;
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R = t2+t1;
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if(i>0)
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{
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hfsq=0.5*f*f;
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if(k==0)
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return f-(hfsq-s*(hfsq+R));
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else
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return dk*ln2_hi-((hfsq-(s*(hfsq+R)+dk*ln2_lo))-f);
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}
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else
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{
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if(k==0)
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return f-s*(f-R);
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else
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return dk*ln2_hi-((s*(f-R)-dk*ln2_lo)-f);
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}
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}
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#endif /* PPC_FLOATING_POINT_SUPPORT */
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/****************************************************************************/
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double
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log(double x)
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{
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double result;
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/* ZZZ when do we consider 'x' to be invalid? If it's close
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* enough to zero or negative. How large is epsilon, and how
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* do we return minus infinity?
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*/
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if(x > 0.0)
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{
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result = __log(x);
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}
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else
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{
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/* ZZZ this should be minus infinity */
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result = -HUGE_VAL;
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errno = ERANGE;
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}
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return(result);
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}
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/****************************************************************************/
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#endif /* FLOATING_POINT_SUPPORT */
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