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 */
19
20#include <math.h>
21#include <math_private.h>
22#include <libm-alias-double.h>
23
24double
25__ceil(double x)
26{
27 int64_t i0,i;
28 int32_t j0;
29 EXTRACT_WORDS64(i0,x);
30 j0 = ((i0>>52)&0x7ff)-0x3ff;
31 if(j0<=51) {
32 if(j0<0) {
33 /* return 0*sign(x) if |x|<1 */
34 if(i0<0) {i0=INT64_C(0x8000000000000000);}
35 else if(i0!=0) { i0=INT64_C(0x3ff0000000000000);}
36 } else {
37 i = INT64_C(0x000fffffffffffff)>>j0;
38 if((i0&i)==0) return x; /* x is integral */
39 if(i0>0) i0 += UINT64_C(0x0010000000000000)>>j0;
40 i0 &= (~i);
41 }
42 } else {
43 if(j0==0x400) return x+x; /* inf or NaN */
44 else return x; /* x is integral */
45 }
46 INSERT_WORDS64(x,i0);
47 return x;
48}
49#ifndef __ceil
50libm_alias_double (__ceil, ceil)
51#endif
52