1/* s_floorf.c -- float version of s_floor.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: src/lib/msun/src/s_floorf.c,v 1.7 2002/05/28 18:15:04 alfred Exp $";
18#endif
19
20/*
21 * floorf(x)
22 * Return x rounded toward -inf to integral value
23 * Method:
24 *	Bit twiddling.
25 * Exception:
26 *	Inexact flag raised if x not equal to floorf(x).
27 */
28
29#include "math.h"
30#include "math_private.h"
31
32static const float huge = 1.0e30;
33
34float
35floorf(float x)
36{
37	int32_t i0,j0;
38	u_int32_t i;
39	GET_FLOAT_WORD(i0,x);
40	j0 = ((i0>>23)&0xff)-0x7f;
41	if(j0<23) {
42	    if(j0<0) { 	/* raise inexact if x != 0 */
43		if(huge+x>(float)0.0) {/* return 0*sign(x) if |x|<1 */
44		    if(i0>=0) {i0=0;}
45		    else if((i0&0x7fffffff)!=0)
46			{ i0=0xbf800000;}
47		}
48	    } else {
49		i = (0x007fffff)>>j0;
50		if((i0&i)==0) return x; /* x is integral */
51		if(huge+x>(float)0.0) {	/* raise inexact flag */
52		    if(i0<0) i0 += (0x00800000)>>j0;
53		    i0 &= (~i);
54		}
55	    }
56	} else {
57	    if(j0==0x80) return x+x;	/* inf or NaN */
58	    else return x;		/* x is integral */
59	}
60	SET_FLOAT_WORD(x,i0);
61	return x;
62}
63