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 /*
17 * floorf(x)
18 * Return x rounded toward -inf to integral value
19 * Method:
20 * Bit twiddling.
21 * Exception:
22 * Inexact flag raised if x not equal to floorf(x).
23 */
24
25 #include "math.h"
26 #include "math_private.h"
27
28 static const float huge = 1.0e30;
29
30 float
floorf(float x)31 floorf(float x)
32 {
33 int32_t i0,jj0;
34 u_int32_t i;
35 GET_FLOAT_WORD(i0,x);
36 jj0 = ((i0>>23)&0xff)-0x7f;
37 if(jj0<23) {
38 if(jj0<0) { /* raise inexact if x != 0 */
39 if(huge+x>(float)0.0) {/* return 0*sign(x) if |x|<1 */
40 if(i0>=0) {i0=0;}
41 else if((i0&0x7fffffff)!=0)
42 { i0=0xbf800000;}
43 }
44 } else {
45 i = (0x007fffff)>>jj0;
46 if((i0&i)==0) return x; /* x is integral */
47 if(huge+x>(float)0.0) { /* raise inexact flag */
48 if(i0<0) i0 += (0x00800000)>>jj0;
49 i0 &= (~i);
50 }
51 }
52 } else {
53 if(jj0==0x80) return x+x; /* inf or NaN */
54 else return x; /* x is integral */
55 }
56 SET_FLOAT_WORD(x,i0);
57 return x;
58 }
59