s_logbf.c revision 97409 
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#ifndef lint
17static char rcsid[] = "$FreeBSD: head/lib/msun/src/s_logbf.c 97409 2002-05-28 17:51:46Z alfred $";
18#endif
19
20#include "math.h"
21#include "math_private.h"
22
23	float logbf(float x)
24{
25	int32_t ix;
26	GET_FLOAT_WORD(ix,x);
27	ix &= 0x7fffffff;			/* high |x| */
28	if(ix==0) return (float)-1.0/fabsf(x);
29	if(ix>=0x7f800000) return x*x;
30	if((ix>>=23)==0) 			/* IEEE 754 logb */
31		return -126.0;
32	else
33		return (float) (ix-127);
34}
35