1 /* origin: FreeBSD /usr/src/lib/msun/src/e_scalb.c */ 2 /* 3 * ==================================================== 4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 5 * 6 * Developed at SunSoft, 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 * scalb(x, fn) is provide for 14 * passing various standard test suite. One 15 * should use scalbn() instead. 16 */ 17 18 #define _GNU_SOURCE 19 #include <math.h> 20 21 double scalb(double x, double fn) 22 { 23 if (isnan(x) || isnan(fn)) 24 return x*fn; 25 if (!isfinite(fn)) { 26 if (fn > 0.0) 27 return x*fn; 28 else 29 return x/(-fn); 30 } 31 if (rint(fn) != fn) return (fn-fn)/(fn-fn); 32 if ( fn > 65000.0) return scalbn(x, 65000); 33 if (-fn > 65000.0) return scalbn(x,-65000); 34 return scalbn(x,(int)fn); 35 } 36