1 /* @(#)e_scalb.c 5.1 93/09/24 */ 2 /* 3 * ==================================================== 4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 5 * 6 * Developed at SunPro, a Sun Microsystems, Inc. business. 7 * Permission to use, copy, modify, and distribute this 8 * software is freely granted, provided that this notice 9 * is preserved. 10 * ==================================================== 11 */ 12 13 #ifndef lint 14 static char rcsid[] = "$FreeBSD$"; 15 #endif 16 17 /* 18 * __ieee754_scalb(x, fn) is provide for 19 * passing various standard test suite. One 20 * should use scalbn() instead. 21 */ 22 23 #include "math.h" 24 #include "math_private.h" 25 26 /* XXX lost declaration of this and isinf() in math.h but still have funcs. */ 27 int (isnan)(float x); 28 29 #ifdef _SCALB_INT 30 double 31 __ieee754_scalb(double x, int fn) 32 #else 33 double 34 __ieee754_scalb(double x, double fn) 35 #endif 36 { 37 #ifdef _SCALB_INT 38 return scalbn(x,fn); 39 #else 40 if ((isnan)(x)||(isnan)(fn)) return x*fn; 41 if (!finite(fn)) { 42 if(fn>0.0) return x*fn; 43 else return x/(-fn); 44 } 45 if (rint(fn)!=fn) return (fn-fn)/(fn-fn); 46 if ( fn > 65000.0) return scalbn(x, 65000); 47 if (-fn > 65000.0) return scalbn(x,-65000); 48 return scalbn(x,(int)fn); 49 #endif 50 } 51