1*05a0b428SJohn Marino /* @(#)s_floor.c 5.1 93/09/24 */
2*05a0b428SJohn Marino /*
3*05a0b428SJohn Marino * ====================================================
4*05a0b428SJohn Marino * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
5*05a0b428SJohn Marino *
6*05a0b428SJohn Marino * Developed at SunPro, a Sun Microsystems, Inc. business.
7*05a0b428SJohn Marino * Permission to use, copy, modify, and distribute this
8*05a0b428SJohn Marino * software is freely granted, provided that this notice
9*05a0b428SJohn Marino * is preserved.
10*05a0b428SJohn Marino * ====================================================
11*05a0b428SJohn Marino */
12*05a0b428SJohn Marino
13*05a0b428SJohn Marino /*
14*05a0b428SJohn Marino * truncf(x)
15*05a0b428SJohn Marino * Return x rounded toward 0 to integral value
16*05a0b428SJohn Marino * Method:
17*05a0b428SJohn Marino * Bit twiddling.
18*05a0b428SJohn Marino * Exception:
19*05a0b428SJohn Marino * Inexact flag raised if x not equal to truncf(x).
20*05a0b428SJohn Marino */
21*05a0b428SJohn Marino
22*05a0b428SJohn Marino #include "math.h"
23*05a0b428SJohn Marino #include "math_private.h"
24*05a0b428SJohn Marino
25*05a0b428SJohn Marino static const float huge = 1.0e30F;
26*05a0b428SJohn Marino
27*05a0b428SJohn Marino float
truncf(float x)28*05a0b428SJohn Marino truncf(float x)
29*05a0b428SJohn Marino {
30*05a0b428SJohn Marino int32_t i0,jj0;
31*05a0b428SJohn Marino u_int32_t i;
32*05a0b428SJohn Marino GET_FLOAT_WORD(i0,x);
33*05a0b428SJohn Marino jj0 = ((i0>>23)&0xff)-0x7f;
34*05a0b428SJohn Marino if(jj0<23) {
35*05a0b428SJohn Marino if(jj0<0) { /* raise inexact if x != 0 */
36*05a0b428SJohn Marino if(huge+x>0.0F) /* |x|<1, so return 0*sign(x) */
37*05a0b428SJohn Marino i0 &= 0x80000000;
38*05a0b428SJohn Marino } else {
39*05a0b428SJohn Marino i = (0x007fffff)>>jj0;
40*05a0b428SJohn Marino if((i0&i)==0) return x; /* x is integral */
41*05a0b428SJohn Marino if(huge+x>0.0F) /* raise inexact flag */
42*05a0b428SJohn Marino i0 &= (~i);
43*05a0b428SJohn Marino }
44*05a0b428SJohn Marino } else {
45*05a0b428SJohn Marino if(jj0==0x80) return x+x; /* inf or NaN */
46*05a0b428SJohn Marino else return x; /* x is integral */
47*05a0b428SJohn Marino }
48*05a0b428SJohn Marino SET_FLOAT_WORD(x,i0);
49*05a0b428SJohn Marino return x;
50*05a0b428SJohn Marino }
51