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/* @(#)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.
 * ====================================================
 */

/*
 * ceil(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 double huge = 1.0e300;

double
__ceil(double x)
{
	int32_t i0,i1,j0;
	u_int32_t i,j;
	EXTRACT_WORDS(i0,i1,x);
	j0 = ((i0>>20)&0x7ff)-0x3ff;
	if(j0<20) {
	    if(j0<0) {	/* raise inexact if x != 0 */
		math_force_eval(huge+x);
		/* return 0*sign(x) if |x|<1 */
		if(i0<0) {i0=0x80000000;i1=0;}
		else if((i0|i1)!=0) { i0=0x3ff00000;i1=0;}
	    } else {
		i = (0x000fffff)>>j0;
		if(((i0&i)|i1)==0) return x; /* x is integral */
		math_force_eval(huge+x);	/* raise inexact flag */
		if(i0>0) i0 += (0x00100000)>>j0;
		i0 &= (~i); i1=0;
	    }
	} else if (j0>51) {
	    if(j0==0x400) return x+x;	/* inf or NaN */
	    else return x;		/* x is integral */
	} else {
	    i = ((u_int32_t)(0xffffffff))>>(j0-20);
	    if((i1&i)==0) return x;	/* x is integral */
	    math_force_eval(huge+x);		/* raise inexact flag */
	    if(i0>0) {
		if(j0==20) i0+=1;
		else {
		    j = i1 + (1<<(52-j0));
		    if(j<i1) i0+=1;	/* got a carry */
		    i1 = j;
		}
	    }
	    i1 &= (~i);
	}
	INSERT_WORDS(x,i0,i1);
	return x;
}
#ifndef __ceil
weak_alias (__ceil, ceil)
# ifdef NO_LONG_DOUBLE
strong_alias (__ceil, __ceill)
weak_alias (__ceil, ceill)
# endif
#endif