1286438Sbapt/* @(#)s_floor.c 5.1 93/09/24 */
2286438Sbapt/*
3286438Sbapt * ====================================================
4286438Sbapt * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
5286438Sbapt *
6286438Sbapt * Developed at SunPro, a Sun Microsystems, Inc. business.
7286438Sbapt * Permission to use, copy, modify, and distribute this
8286438Sbapt * software is freely granted, provided that this notice
9286438Sbapt * is preserved.
10286438Sbapt * ====================================================
11286438Sbapt */
12286438Sbapt
13286438Sbapt#include <sys/cdefs.h>
14286438Sbapt__FBSDID("$FreeBSD$");
15312336Sbapt
16286438Sbapt/*
17286438Sbapt * truncf(x)
18286438Sbapt * Return x rounded toward 0 to integral value
19286438Sbapt * Method:
20286438Sbapt *	Bit twiddling.
21286438Sbapt * Exception:
22286438Sbapt *	Inexact flag raised if x not equal to truncf(x).
23286438Sbapt */
24286438Sbapt
25286438Sbapt#include "math.h"
26286438Sbapt#include "math_private.h"
27286438Sbapt
28286438Sbaptstatic const float huge = 1.0e30F;
29286438Sbapt
30286438Sbaptfloat
31286438Sbapttruncf(float x)
32286438Sbapt{
33286438Sbapt	int32_t i0,j0;
34286438Sbapt	u_int32_t i;
35286438Sbapt	GET_FLOAT_WORD(i0,x);
36286438Sbapt	j0 = ((i0>>23)&0xff)-0x7f;
37286438Sbapt	if(j0<23) {
38286438Sbapt	    if(j0<0) { 	/* raise inexact if x != 0 */
39286438Sbapt		if(huge+x>0.0F)		/* |x|<1, so return 0*sign(x) */
40286438Sbapt		    i0 &= 0x80000000;
41286438Sbapt	    } else {
42286438Sbapt		i = (0x007fffff)>>j0;
43286438Sbapt		if((i0&i)==0) return x; /* x is integral */
44286438Sbapt		if(huge+x>0.0F)		/* raise inexact flag */
45286438Sbapt		    i0 &= (~i);
46286438Sbapt	    }
47286438Sbapt	} else {
48286438Sbapt	    if(j0==0x80) return x+x;	/* inf or NaN */
49325928Sbapt	    else return x;		/* x is integral */
50325928Sbapt	}
51325928Sbapt	SET_FLOAT_WORD(x,i0);
52286438Sbapt	return x;
53286438Sbapt}
54312336Sbapt