/* @(#)s_ceil.c 5.1 93/09/24 */
/*
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunPro, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 */

/*
 * ceill(x)
 * Return x rounded toward -inf to integral value
 * Method:
 *      Bit twiddling.
 * Exception:
 *      Inexact flag raised if x not equal to ceil(x).
 */

#include <math.h>

#include "math_private.h"

static const long double huge = 1.0e4930L;

long double
ceill(long double x)
{
        int64_t i0,i1,jj0;
        u_int64_t i,j;
        GET_LDOUBLE_WORDS64(i0,i1,x);
        jj0 = ((i0>>48)&0x7fff)-0x3fff;
        if(jj0<48) {
            if(jj0<0) {         /* raise inexact if x != 0 */
                if(huge+x>0.0) {/* return 0*sign(x) if |x|<1 */
                    if(i0<0) {i0=0x8000000000000000ULL;i1=0;}
                    else if((i0|i1)!=0) { i0=0x3fff000000000000ULL;i1=0;}
                }
            } else {
                i = (0x0000ffffffffffffULL)>>jj0;
                if(((i0&i)|i1)==0) return x; /* x is integral */
                if(huge+x>0.0) {        /* raise inexact flag */
                    if(i0>0) i0 += (0x0001000000000000LL)>>jj0;
                    i0 &= (~i); i1=0;
                }
            }
        } else if (jj0>111) {
            if(jj0==0x4000) return x+x; /* inf or NaN */
            else return x;              /* x is integral */
        } else {
            i = -1ULL>>(jj0-48);
            if((i1&i)==0) return x;     /* x is integral */
            if(huge+x>0.0) {            /* raise inexact flag */
                if(i0>0) {
                    if(jj0==48) i0+=1;
                    else {
                        j = i1+(1LL<<(112-jj0));
                        if(j<i1) i0 +=1 ;       /* got a carry */
                        i1=j;
                    }
                }
                i1 &= (~i);
            }
        }
        SET_LDOUBLE_WORDS64(x,i0,i1);
        return x;
}