1 /* @(#)s_ilogb.c 5.1 93/09/24 */
3 * ====================================================
4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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
10 * ====================================================
13 #if defined(LIBM_SCCS) && !defined(lint)
14 static char rcsid[] = "$NetBSD: s_ilogb.c,v 1.9 1995/05/10 20:47:28 jtc Exp $";
18 * return the binary exponent of non-zero x
19 * ilogb(0) = 0x80000001
20 * ilogb(inf/NaN) = 0x7fffffff (no signal is raised)
24 #include "math_private.h"
40 return FP_ILOGB0; /* ilogb(0) = FP_ILOGB0 */
41 else /* subnormal x */
43 for (ix = -1043; lx>0; lx<<=1) ix -=1;
45 for (ix = -1022,hx<<=11; hx>0; hx<<=1) ix -=1;
49 else if (hx<0x7ff00000) return (hx>>20)-1023;
50 else return FP_ILOGBNAN;
52 weak_alias (__ilogb, ilogb)
54 strong_alias (__ilogb, __ilogbl)
55 weak_alias (__ilogb, ilogbl)