s_logbf.c revision 50476 
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 50476 1999-08-28 00:22:10Z peter $";
18#endif
19
20#include "math.h"
21#include "math_private.h"
22
23#ifdef __STDC__
24	float logbf(float x)
25#else
26	float logbf(x)
27	float x;
28#endif
29{
30	int32_t ix;
31	GET_FLOAT_WORD(ix,x);
32	ix &= 0x7fffffff;			/* high |x| */
33	if(ix==0) return (float)-1.0/fabsf(x);
34	if(ix>=0x7f800000) return x*x;
35	if((ix>>=23)==0) 			/* IEEE 754 logb */
36		return -126.0;
37	else
38		return (float) (ix-127);
39}
40