Update.
[glibc.git] / sysdeps / libm-ieee754 / s_ilogbf.c
blobe652b93619662e2ebc30a8c708491ba1f3aa7240
1 /* s_ilogbf.c -- float version of s_ilogb.c.
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3 */
5 /*
6 * ====================================================
7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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 * ====================================================
16 #if defined(LIBM_SCCS) && !defined(lint)
17 static char rcsid[] = "$NetBSD: s_ilogbf.c,v 1.4 1995/05/10 20:47:31 jtc Exp $";
18 #endif
20 #include "math.h"
21 #include "math_private.h"
23 #ifdef __STDC__
24 int __ilogbf(float x)
25 #else
26 int __ilogbf(x)
27 float x;
28 #endif
30 int32_t hx,ix;
32 GET_FLOAT_WORD(hx,x);
33 hx &= 0x7fffffff;
34 if(hx<0x00800000) {
35 if(hx==0)
36 return FP_ILOGB0; /* ilogb(0) = FP_ILOGB0 */
37 else /* subnormal x */
38 for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1;
39 return ix;
41 else if (hx<0x7f800000) return (hx>>23)-127;
42 else return FP_ILOGBNAN;
44 weak_alias (__ilogbf, ilogbf)