prime/src/Runtime/w_pow.c

59 lines
1.4 KiB
C

/* @(#)w_pow.c 1.2 95/01/04 */
/*
* ====================================================
* 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 pow(x,y) return x**y
*/
#include "fdlibm.h"
#ifdef __STDC__
double pow(double x, double y) /* wrapper pow */
#else
double pow(x, y) /* wrapper pow */
double x, y;
#endif
{
#ifdef _IEEE_LIBM
return __ieee754_pow(x, y);
#else
double z;
z = __ieee754_pow(x, y);
if (_LIB_VERSION == _IEEE_ || isnan(y))
return z;
if (isnan(x)) {
if (y == 0.0)
return __kernel_standard(x, y, 42); /* pow(NaN,0.0) */
else
return z;
}
if (x == 0.0) {
if (y == 0.0)
return __kernel_standard(x, y, 20); /* pow(0.0,0.0) */
if (isfinite(y) && y < 0.0)
return __kernel_standard(x, y, 23); /* pow(0.0,negative) */
return z;
}
if (!isfinite(z)) {
if (isfinite(x) && isfinite(y)) {
if (isnan(z))
return __kernel_standard(x, y, 24); /* pow neg**non-int */
else
return __kernel_standard(x, y, 21); /* pow overflow */
}
}
if (z == 0.0 && isfinite(x) && isfinite(y))
return __kernel_standard(x, y, 22); /* pow underflow */
return z;
#endif
}