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#include <sys/cdefs.h>
17__FBSDID("$FreeBSD$");
18
19/*
20 * floorf(x)
21 * Return x rounded toward -inf to integral value
22 * Method:
23 *	Bit twiddling.
24 * Exception:
25 *	Inexact flag raised if x not equal to floorf(x).
26 */
27
28#include "math.h"
29#include "math_private.h"
30
31static const float huge = 1.0e30;
32
33float
34floorf(float x)
35{
36	int32_t i0,j0;
37	u_int32_t i;
38	GET_FLOAT_WORD(i0,x);
39	j0 = ((i0>>23)&0xff)-0x7f;
40	if(j0<23) {
41	    if(j0<0) { 	/* raise inexact if x != 0 */
42		if(huge+x>(float)0.0) {/* return 0*sign(x) if |x|<1 */
43		    if(i0>=0) {i0=0;}
44		    else if((i0&0x7fffffff)!=0)
45			{ i0=0xbf800000;}
46		}
47	    } else {
48		i = (0x007fffff)>>j0;
49		if((i0&i)==0) return x; /* x is integral */
50		if(huge+x>(float)0.0) {	/* raise inexact flag */
51		    if(i0<0) i0 += (0x00800000)>>j0;
52		    i0 &= (~i);
53		}
54	    }
55	} else {
56	    if(j0==0x80) return x+x;	/* inf or NaN */
57	    else return x;		/* x is integral */
58	}
59	SET_FLOAT_WORD(x,i0);
60	return x;
61}
62