1 /* s_logbf.c -- float version of s_logb.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 #include <sys/cdefs.h>
17 #if defined(LIBM_SCCS) && !defined(lint)
18 __RCSID("$NetBSD: s_logbf.c,v 1.7 2002/05/26 22:01:57 wiz Exp $");
19 #endif
20
21 #include "math.h"
22 #include "math_private.h"
23
24 float
logbf(float x)25 logbf(float x)
26 {
27 int32_t ix;
28 GET_FLOAT_WORD(ix,x);
29 ix &= 0x7fffffff; /* high |x| */
30 if(ix==0) return (float)-1.0/fabsf(x);
31 if(ix>=0x7f800000) return x*x;
32 if((ix>>=23)==0) /* IEEE 754 logb */
33 return -126.0;
34 else
35 return (float) (ix-127);
36 }
37