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

97 lines
1.9 KiB
C

/* wf_pow.c -- float version of w_pow.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 powf(x,y) return x**y
*/
#include "fdlibm.h"
#if __OBSOLETE_MATH
#include <errno.h>
#ifdef __STDC__
float powf(float x, float y) /* wrapper powf */
#else
float powf(x,y) /* wrapper powf */
float x,y;
#endif
{
#ifdef _IEEE_LIBM
return __ieee754_powf(x,y);
#else
float z;
z=__ieee754_powf(x,y);
if(_LIB_VERSION == _IEEE_|| isnan(y)) return z;
if(isnan(x)) {
if(y==0.0f) {
/* powf(NaN,0.0) */
/* Not an error. */
return 1.0f;
} else
return z;
}
if(x==0.0f){
if(y==0.0f) {
/* powf(0.0,0.0) */
/* Not an error. */
return 1.0f;
}
if(finitef(y)&&y<0.0f) {
/* 0**neg */
errno = ERANGE;
}
return z;
}
if(!finitef(z)) {
if(finitef(x)&&finitef(y)) {
if(isnan(z)) {
/* neg**non-integral */
errno = EDOM;
/* Use a float divide, to avoid a soft-float double
divide call on single-float only targets. */
return 0.0f/0.0f;
} else {
/* powf(x,y) overflow */
errno = ERANGE;
if(x<0.0f&&rintf(y)!=y)
return -HUGE_VALF;
return HUGE_VALF;
}
}
}
if(z==0.0f&&finitef(x)&&finitef(y)) {
/* powf(x,y) underflow */
errno = ERANGE;
return 0.0f;
}
return z;
#endif
}
#ifdef _DOUBLE_IS_32BITS
#ifdef __STDC__
double pow(double x, double y)
#else
double pow(x,y)
double x,y;
#endif
{
return (double) powf((float) x, (float) y);
}
#endif /* defined(_DOUBLE_IS_32BITS) */
#endif /* __OBSOLETE_MATH */