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#define NO_MATH_REDIRECT
21#include <math.h>
22#include <math_private.h>
23#include <libm-alias-double.h>
24
25double
26__ceil(double x)
27{
28 int64_t i0,i;
29 int32_t j0;
30 EXTRACT_WORDS64(i0,x);
31 j0 = ((i0>>52)&0x7ff)-0x3ff;
32 if(j0<=51) {
33 if(j0<0) {
34 /* return 0*sign(x) if |x|<1 */
35 if(i0<0) {i0=INT64_C(0x8000000000000000);}
36 else if(i0!=0) { i0=INT64_C(0x3ff0000000000000);}
37 } else {
38 i = INT64_C(0x000fffffffffffff)>>j0;
39 if((i0&i)==0) return x; /* x is integral */
40 if(i0>0) i0 += UINT64_C(0x0010000000000000)>>j0;
41 i0 &= (~i);
42 }
43 } else {
44 if(j0==0x400) return x+x; /* inf or NaN */
45 else return x; /* x is integral */
46 }
47 INSERT_WORDS64(x,i0);
48 return x;
49}
50#ifndef __ceil
51libm_alias_double (__ceil, ceil)
52#endif
53