Subversion Repositories shark

Rev

Rev 1618 | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
2 pj 1
/* s_ilogbf.c -- float version of s_ilogb.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
17
static char rcsid[] = "$\Id: s_ilogbf.c,v 1.2 1995/05/30 05:49:46 rgrimes Exp $";
18
#endif
19
 
20
#include "math.h"
21
#include "math_private.h"
22
 
23
#ifdef __STDC__
24
        int ilogbf(float x)
25
#else
26
        int ilogbf(x)
27
        float x;
28
#endif
29
{
30
        int32_t hx,ix;
31
 
32
        GET_FLOAT_WORD(hx,x);
33
        hx &= 0x7fffffff;
34
        if(hx<0x00800000) {
35
            if(hx==0)
36
                return 0x80000001;      /* ilogb(0) = 0x80000001 */
37
            else                        /* subnormal x */
38
                for (ix = -126,hx<<=8; hx>0; hx<<=1) ix -=1;
39
            return ix;
40
        }
41
        else if (hx<0x7f800000) return (hx>>23)-127;
42
        else return 0x7fffffff;
43
}