1*05a0b428SJohn Marino /* @(#)s_ceil.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 * ceil(x)
15*05a0b428SJohn Marino * Return x rounded toward -inf 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 ceil(x).
20*05a0b428SJohn Marino */
21*05a0b428SJohn Marino
22*05a0b428SJohn Marino #include <float.h>
23*05a0b428SJohn Marino #include <math.h>
24*05a0b428SJohn Marino
25*05a0b428SJohn Marino #include "math_private.h"
26*05a0b428SJohn Marino
27*05a0b428SJohn Marino static const double huge = 1.0e300;
28*05a0b428SJohn Marino
29*05a0b428SJohn Marino double
ceil(double x)30*05a0b428SJohn Marino ceil(double x)
31*05a0b428SJohn Marino {
32*05a0b428SJohn Marino int32_t i0,i1,jj0;
33*05a0b428SJohn Marino u_int32_t i,j;
34*05a0b428SJohn Marino EXTRACT_WORDS(i0,i1,x);
35*05a0b428SJohn Marino jj0 = ((i0>>20)&0x7ff)-0x3ff;
36*05a0b428SJohn Marino if(jj0<20) {
37*05a0b428SJohn Marino if(jj0<0) { /* raise inexact if x != 0 */
38*05a0b428SJohn Marino if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */
39*05a0b428SJohn Marino if(i0<0) {i0=0x80000000;i1=0;}
40*05a0b428SJohn Marino else if((i0|i1)!=0) { i0=0x3ff00000;i1=0;}
41*05a0b428SJohn Marino }
42*05a0b428SJohn Marino } else {
43*05a0b428SJohn Marino i = (0x000fffff)>>jj0;
44*05a0b428SJohn Marino if(((i0&i)|i1)==0) return x; /* x is integral */
45*05a0b428SJohn Marino if(huge+x>0.0) { /* raise inexact flag */
46*05a0b428SJohn Marino if(i0>0) i0 += (0x00100000)>>jj0;
47*05a0b428SJohn Marino i0 &= (~i); i1=0;
48*05a0b428SJohn Marino }
49*05a0b428SJohn Marino }
50*05a0b428SJohn Marino } else if (jj0>51) {
51*05a0b428SJohn Marino if(jj0==0x400) return x+x; /* inf or NaN */
52*05a0b428SJohn Marino else return x; /* x is integral */
53*05a0b428SJohn Marino } else {
54*05a0b428SJohn Marino i = ((u_int32_t)(0xffffffff))>>(jj0-20);
55*05a0b428SJohn Marino if((i1&i)==0) return x; /* x is integral */
56*05a0b428SJohn Marino if(huge+x>0.0) { /* raise inexact flag */
57*05a0b428SJohn Marino if(i0>0) {
58*05a0b428SJohn Marino if(jj0==20) i0+=1;
59*05a0b428SJohn Marino else {
60*05a0b428SJohn Marino j = i1 + (1<<(52-jj0));
61*05a0b428SJohn Marino if(j<i1) i0+=1; /* got a carry */
62*05a0b428SJohn Marino i1 = j;
63*05a0b428SJohn Marino }
64*05a0b428SJohn Marino }
65*05a0b428SJohn Marino i1 &= (~i);
66*05a0b428SJohn Marino }
67*05a0b428SJohn Marino }
68*05a0b428SJohn Marino INSERT_WORDS(x,i0,i1);
69*05a0b428SJohn Marino return x;
70*05a0b428SJohn Marino }
71*05a0b428SJohn Marino
72*05a0b428SJohn Marino #if LDBL_MANT_DIG == DBL_MANT_DIG
73*05a0b428SJohn Marino __strong_alias(ceill, ceil);
74*05a0b428SJohn Marino #endif /* LDBL_MANT_DIG == DBL_MANT_DIG */
75