s_rintf.c revision 175480 
1/* s_rintf.c -- float version of s_rint.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: head/lib/msun/src/s_rintf.c 175480 2008-01-19 16:37:57Z bde $";
18#endif
19
20#include <float.h>
21#include <stdint.h>
22
23#include "math.h"
24#include "math_private.h"
25
26static const float
27TWO23[2]={
28  8.3886080000e+06, /* 0x4b000000 */
29 -8.3886080000e+06, /* 0xcb000000 */
30};
31
32float
33rintf(float x)
34{
35	int32_t i0,j0,sx;
36	float w,t;
37	GET_FLOAT_WORD(i0,x);
38	sx = (i0>>31)&1;
39	j0 = ((i0>>23)&0xff)-0x7f;
40	if(j0<23) {
41	    if(j0<0) {
42		if((i0&0x7fffffff)==0) return x;
43		STRICT_ASSIGN(float,w,TWO23[sx]+x);
44	        t =  w-TWO23[sx];
45		GET_FLOAT_WORD(i0,t);
46		SET_FLOAT_WORD(t,(i0&0x7fffffff)|(sx<<31));
47	        return t;
48	    }
49	    STRICT_ASSIGN(float,w,TWO23[sx]+x);
50	    return w-TWO23[sx];
51	}
52	if(j0==0x80) return x+x;	/* inf or NaN */
53	else return x;			/* x is integral */
54}
55