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 "math.h"
17 #include "math_private.h"
18 
19 float
20 logbf(float x)
21 {
22 	int32_t ix;
23 	GET_FLOAT_WORD(ix,x);
24 	ix &= 0x7fffffff;			/* high |x| */
25 	if(ix==0) return (float)-1.0/fabsf(x);
26 	if(ix>=0x7f800000) return x*x;
27 	if((ix>>=23)==0) 			/* IEEE 754 logb */
28 		return -126.0;
29 	else
30 		return (float) (ix-127);
31 }
32