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 1.6 1999/07/02 15:37:43 simonb Exp $");
19#endif
20
21#include "math.h"
22#include "math_private.h"
23
24float
25logbf(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