1/* @(#)s_ceil.c 5.1 93/09/24 */
2/*
3 * ====================================================
4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
5 *
6 * Developed at SunPro, a Sun Microsystems, Inc. business.
7 * Permission to use, copy, modify, and distribute this
8 * software is freely granted, provided that this notice
9 * is preserved.
10 * ====================================================
11 */
12
13/*
14 * ceil(x)
15 * Return x rounded toward -inf to integral value
16 * Method:
17 * Bit twiddling.
18 * Exception:
19 * Inexact flag raised if x not equal to ceil(x).
20 */
21
22#include <math.h>
23#include <math_private.h>
24
25static const double huge = 1.0e300;
26
27double
28__ceil(double x)
29{
30 int64_t i0,i;
31 int32_t j0;
32 EXTRACT_WORDS64(i0,x);
33 j0 = ((i0>>52)&0x7ff)-0x3ff;
34 if(j0<=51) {
35 if(j0<0) { /* raise inexact if x != 0 */
36 math_force_eval(huge+x);/* return 0*sign(x) if |x|<1 */
37 if(i0<0) {i0=INT64_C(0x8000000000000000);}
38 else if(i0!=0) { i0=INT64_C(0x3ff0000000000000);}
39 } else {
40 i = INT64_C(0x000fffffffffffff)>>j0;
41 if((i0&i)==0) return x; /* x is integral */
42 math_force_eval(huge+x); /* raise inexact flag */
43 if(i0>0) i0 += UINT64_C(0x0010000000000000)>>j0;
44 i0 &= (~i);
45 }
46 } else {
47 if(j0==0x400) return x+x; /* inf or NaN */
48 else return x; /* x is integral */
49 }
50 INSERT_WORDS64(x,i0);
51 return x;
52}
53#ifndef __ceil
54weak_alias (__ceil, ceil)
55# ifdef NO_LONG_DOUBLE
56strong_alias (__ceil, __ceill)
57weak_alias (__ceil, ceill)
58# endif
59#endif
60