/* @(#)w_pow.c 5.2 93/10/01 */ /* * ==================================================== * 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. * ==================================================== */ /* FUNCTION <>, <>---x to the power y INDEX pow INDEX powf SYNOPSIS #include double pow(double <[x]>, double <[y]>); float powf(float <[x]>, float <[y]>); DESCRIPTION <> and <> calculate <[x]> raised to the exponent <[y]>. @tex (That is, $x^y$.) @end tex RETURNS On success, <> and <> return the value calculated. When the argument values would produce overflow, <> returns <> and set <> to <>. If the argument <[x]> passed to <> or <> is a negative noninteger, and <[y]> is also not an integer, then <> is set to <>. If <[x]> and <[y]> are both 0, then <> and <> return <<1>>. PORTABILITY <> is ANSI C. <> is an extension. */ /* * wrapper pow(x,y) return x**y */ #include "fdlibm.h" #if __OBSOLETE_MATH #include #ifndef _DOUBLE_IS_32BITS #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) { /* pow(NaN,0.0) */ /* Not an error. */ return 1.0; } else return z; } if(x==0.0){ if(y==0.0) { /* pow(0.0,0.0) */ /* Not an error. */ return 1.0; } if(finite(y)&&y<0.0) { /* 0**neg */ errno = ERANGE; } return z; } if(!finite(z)) { if(finite(x)&&finite(y)) { if(isnan(z)) { /* neg**non-integral */ errno = EDOM; return 0.0/0.0; } else { /* pow(x,y) overflow */ errno = ERANGE; if(x<0.0&&rint(y)!=y) return -HUGE_VAL; return HUGE_VAL; } } } if(z==0.0&&finite(x)&&finite(y)) { /* pow(x,y) underflow */ errno = ERANGE; return 0.0; } return z; #endif } #endif /* defined(_DOUBLE_IS_32BITS) */ #endif /* __OBSOLETE_MATH */