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 #if defined(LIBM_SCCS) && !defined(lint)
18 __RCSID("$MirOS: src/lib/libm/src/s_floorf.c,v 1.3 2011/10/18 19:46:28 bsiegert Exp $");
19 __RCSID("$NetBSD: s_floorf.c,v 1.8 2008/04/25 22:21:53 christos Exp $");
20 #endif
21
22 /*
23 * floorf(x)
24 * Return x rounded toward -inf to integral value
25 * Method:
26 * Bit twiddling.
27 * Exception:
28 * Inexact flag raised if x not equal to floorf(x).
29 */
30
31 #include "math.h"
32 #include "math_private.h"
33
34 static const float huge = 1.0e30;
35
36 float
floorf(float x)37 floorf(float x)
38 {
39 int32_t i0,jj0;
40 u_int32_t i;
41 GET_FLOAT_WORD(i0,x);
42 jj0 = ((i0>>23)&0xff)-0x7f;
43 if(jj0<23) {
44 if(jj0<0) { /* raise inexact if x != 0 */
45 if(huge+x>(float)0.0) {/* return 0*sign(x) if |x|<1 */
46 if(i0>=0) {i0=0;}
47 else if((i0&0x7fffffff)!=0)
48 { i0=0xbf800000;}
49 }
50 } else {
51 i = (0x007fffff)>>jj0;
52 if((i0&i)==0) return x; /* x is integral */
53 if(huge+x>(float)0.0) { /* raise inexact flag */
54 if(i0<0) i0 += (0x00800000)>>jj0;
55 i0 &= (~i);
56 }
57 }
58 } else {
59 if(jj0==0x80) return x+x; /* inf or NaN */
60 else return x; /* x is integral */
61 }
62 SET_FLOAT_WORD(x,i0);
63 return x;
64 }
65