1 /* sf_floor.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 "fdlibm.h"
26
27 float
floorf(float x)28 floorf(float x)
29 {
30 __int32_t i0, j0;
31 __uint32_t i, ix;
32 GET_FLOAT_WORD(i0, x);
33 ix = (i0 & 0x7fffffff);
34 j0 = (ix >> 23) - 0x7f;
35 if (j0 < 23) {
36 if (j0 < 0) { /* raise inexact if x != 0 */
37 if (i0 >= 0) {
38 i0 = 0;
39 } else if (!FLT_UWORD_IS_ZERO(ix)) {
40 i0 = 0xbf800000;
41 }
42 } else {
43 i = (0x007fffff) >> j0;
44 if ((i0 & i) == 0)
45 return x; /* x is integral */
46 if (i0 < 0)
47 i0 += (0x00800000) >> j0;
48 i0 &= (~i);
49 }
50 } else {
51 if (!FLT_UWORD_IS_FINITE(ix))
52 return x + x; /* inf or NaN */
53 else
54 return x; /* x is integral */
55 }
56 SET_FLOAT_WORD(x, i0);
57 return x;
58 }
59
60 _MATH_ALIAS_f_f(floor)
61
