xref: /freebsd/lib/msun/src/e_scalbf.c (revision 2357939bc239bd5334a169b62313806178dd8f30)
1 /* e_scalbf.c -- float version of e_scalb.c.
2  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3  */
4 
5 /*
6  * ====================================================
7  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
8  *
9  * Developed at SunPro, a Sun Microsystems, Inc. business.
10  * Permission to use, copy, modify, and distribute this
11  * software is freely granted, provided that this notice
12  * is preserved.
13  * ====================================================
14  */
15 
16 #ifndef lint
17 static char rcsid[] = "$FreeBSD$";
18 #endif
19 
20 #include "math.h"
21 #include "math_private.h"
22 
23 /* XXX lost declaration of this and isnan() in math.h but still have funcs. */
24 int	(isnanf)(float x);
25 
26 #ifdef _SCALB_INT
27 float
28 __ieee754_scalbf(float x, int fn)
29 #else
30 float
31 __ieee754_scalbf(float x, float fn)
32 #endif
33 {
34 #ifdef _SCALB_INT
35 	return scalbnf(x,fn);
36 #else
37 	if ((isnanf)(x)||(isnanf)(fn)) return x*fn;
38 	if (!finitef(fn)) {
39 	    if(fn>(float)0.0) return x*fn;
40 	    else       return x/(-fn);
41 	}
42 	if (rintf(fn)!=fn) return (fn-fn)/(fn-fn);
43 	if ( fn > (float)65000.0) return scalbnf(x, 65000);
44 	if (-fn > (float)65000.0) return scalbnf(x,-65000);
45 	return scalbnf(x,(int)fn);
46 #endif
47 }
48