Update.
[glibc.git] / sysdeps / libm-ieee754 / s_ceill.c
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1 /* s_ceill.c -- long double version of s_ceil.c.
2 * Conversion to long double by Ulrich Drepper,
3 * Cygnus Support, drepper@cygnus.com.
4 */
6 /*
7 * ====================================================
8 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
10 * Developed at SunPro, a Sun Microsystems, Inc. business.
11 * Permission to use, copy, modify, and distribute this
12 * software is freely granted, provided that this notice
13 * is preserved.
14 * ====================================================
17 #if defined(LIBM_SCCS) && !defined(lint)
18 static char rcsid[] = "$NetBSD: $";
19 #endif
22 * ceill(x)
23 * Return x rounded toward -inf to integral value
24 * Method:
25 * Bit twiddling.
26 * Exception:
27 * Inexact flag raised if x not equal to ceil(x).
30 #include "math.h"
31 #include "math_private.h"
33 #ifdef __STDC__
34 static const long double huge = 1.0e4930;
35 #else
36 static long double huge = 1.0e4930;
37 #endif
39 #ifdef __STDC__
40 long double __ceill(long double x)
41 #else
42 long double __ceill(x)
43 long double x;
44 #endif
46 int32_t i1,j0;
47 u_int32_t i,j,se,i0,sx;
48 GET_LDOUBLE_WORDS(se,i0,i1,x);
49 sx = (se>>15)&1;
50 j0 = (se&0x7fff)-0x3fff;
51 if(j0<31) {
52 if(j0<0) { /* raise inexact if x != 0 */
53 if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */
54 if(sx) {se=0x8000;i0=0;i1=0;}
55 else if((i0|i1)!=0) { se=0x3fff;i0=0;i1=0;}
57 } else {
58 i = (0x7fffffff)>>j0;
59 if(((i0&i)|i1)==0) return x; /* x is integral */
60 if(huge+x>0.0) { /* raise inexact flag */
61 if(sx==0) {
62 if (j0>0) i0 += (0x80000000)>>j0;
63 else ++se;
65 i0 &= (~i); i1=0;
68 } else if (j0>62) {
69 if(j0==0x4000) return x+x; /* inf or NaN */
70 else return x; /* x is integral */
71 } else {
72 i = ((u_int32_t)(0xffffffff))>>(j0-31);
73 if((i1&i)==0) return x; /* x is integral */
74 if(huge+x>0.0) { /* raise inexact flag */
75 if(sx==0) {
76 if(j0==31) i0+=1;
77 else {
78 j = i1 + (1<<(63-j0));
79 if(j<i1) i0+=1; /* got a carry */
80 i1 = j;
83 i1 &= (~i);
86 SET_LDOUBLE_WORDS(x,se,i0,i1);
87 return x;
89 weak_alias (__ceill, ceill)