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
31 static const float huge = 1.0e30;
32
33 float
floorf(float x)34 floorf(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