newlib-cygwin/newlib/libm/math/wf_log.c

86 lines
1.7 KiB
C

/* wf_log.c -- float version of w_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.
* ====================================================
*/
/*
* wrapper logf(x)
*/
#include "fdlibm.h"
#include <errno.h>
#ifdef __STDC__
float logf(float x) /* wrapper logf */
#else
float logf(x) /* wrapper logf */
float x;
#endif
{
#ifdef _IEEE_LIBM
return __ieee754_logf(x);
#else
float z;
struct exception exc;
z = __ieee754_logf(x);
if(_LIB_VERSION == _IEEE_ || isnanf(x) || x > (float)0.0) return z;
#ifndef HUGE_VAL
#define HUGE_VAL inf
double inf = 0.0;
SET_HIGH_WORD(inf,0x7ff00000); /* set inf to infinite */
#endif
exc.name = "logf";
exc.err = 0;
exc.arg1 = exc.arg2 = (double)x;
if (_LIB_VERSION == _SVID_)
exc.retval = -HUGE;
else
exc.retval = -HUGE_VAL;
if(x==(float)0.0) {
/* logf(0) */
exc.type = SING;
if (_LIB_VERSION == _POSIX_)
errno = ERANGE;
else if (!matherr(&exc)) {
errno = EDOM;
}
} else {
/* logf(x<0) */
exc.type = DOMAIN;
if (_LIB_VERSION == _POSIX_)
errno = EDOM;
else if (!matherr(&exc)) {
errno = EDOM;
}
}
if (exc.err != 0)
errno = exc.err;
return (float)exc.retval;
#endif
}
#ifdef _DOUBLE_IS_32BITS
#ifdef __STDC__
double log(double x)
#else
double log(x)
double x;
#endif
{
return (double) logf((float) x);
}
#endif /* defined(_DOUBLE_IS_32BITS) */