1/* @(#)s_floor.c 5.1 93/09/24 */
2/*
3 * ====================================================
4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
5 *
6 * Developed at SunPro, a Sun Microsystems, Inc. business.
7 * Permission to use, copy, modify, and distribute this
8 * software is freely granted, provided that this notice
9 * is preserved.
10 * ====================================================
11 */
12
13#include <sys/cdefs.h>
14__FBSDID("$FreeBSD$");
15
16/*
17 * truncf(x)
18 * Return x rounded toward 0 to integral value
19 * Method:
20 *	Bit twiddling.
21 * Exception:
22 *	Inexact flag raised if x not equal to truncf(x).
23 */
24
25#include "math.h"
26#include "math_private.h"
27
28static const float huge = 1.0e30F;
29
30float
31truncf(float x)
32{
33	int32_t i0,j0;
34	u_int32_t i;
35	GET_FLOAT_WORD(i0,x);
36	j0 = ((i0>>23)&0xff)-0x7f;
37	if(j0<23) {
38	    if(j0<0) { 	/* raise inexact if x != 0 */
39		if(huge+x>0.0F)		/* |x|<1, so return 0*sign(x) */
40		    i0 &= 0x80000000;
41	    } else {
42		i = (0x007fffff)>>j0;
43		if((i0&i)==0) return x; /* x is integral */
44		if(huge+x>0.0F)		/* raise inexact flag */
45		    i0 &= (~i);
46	    }
47	} else {
48	    if(j0==0x80) return x+x;	/* inf or NaN */
49	    else return x;		/* x is integral */
50	}
51	SET_FLOAT_WORD(x,i0);
52	return x;
53}
54