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/* nearbyintq.c -- __float128 version of s_nearbyint.c.

 * Conversion to IEEE quad long double by Jakub Jelinek, jj@ultra.linux.cz.

 */

/*

 * ====================================================

 * 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.

 * ====================================================

 */

/*

 * nearbyintq(x)

 * Return x rounded to integral value according to the prevailing

 * rounding mode.

 * Method:

 *      Using floating addition.

 * Exception:

 *      Inexact flag raised if x not equal to rintq(x).

 */

#include "quadmath-imp.h"

#ifdef HAVE_FENV_H

# include <fenv.h>

# if defined HAVE_FEHOLDEXCEPT && defined HAVE_FESETENV

#   define USE_FENV_H

# endif

#endif

static const __float128

TWO112[2]={

  5.19229685853482762853049632922009600E+33Q, /* 0x406F000000000000, 0 */

 -5.19229685853482762853049632922009600E+33Q  /* 0xC06F000000000000, 0 */

};

__float128

nearbyintq(__float128 x)

{

#ifdef USE_FENV_H

        fenv_t env;

#endif

        int64_t i0,j0,sx;

        uint64_t i,i1;

        __float128 w,t;

        GET_FLT128_WORDS64(i0,i1,x);

        sx = (((uint64_t)i0)>>63);

        j0 = ((i0>>48)&0x7fff)-0x3fff;

        if(j0<48) {

            if(j0<0) {

                if(((i0&0x7fffffffffffffffLL)|i1)==0) return x;

                i1 |= (i0&0x0000ffffffffffffLL);

                i0 &= 0xffffe00000000000ULL;

                i0 |= ((i1|-i1)>>16)&0x0000800000000000LL;

                SET_FLT128_MSW64(x,i0);

#ifdef USE_FENV_H

                feholdexcept (&env);

#endif

                w = TWO112[sx]+x;

                t = w-TWO112[sx];

#ifdef USE_FENV_H

                fesetenv (&env);

#endif

                GET_FLT128_MSW64(i0,t);

                SET_FLT128_MSW64(t,(i0&0x7fffffffffffffffLL)|(sx<<63));

                return t;

            } else {

                i = (0x0000ffffffffffffLL)>>j0;

                if(((i0&i)|i1)==0) return x; /* x is integral */

                i>>=1;

                if(((i0&i)|i1)!=0) {

                    if(j0==47) i1 = 0x4000000000000000ULL; else

                    i0 = (i0&(~i))|((0x0000200000000000LL)>>j0);

                }

            }

        } else if (j0>111) {

            if(j0==0x4000) return x+x;  /* inf or NaN */

            else return x;              /* x is integral */

        } else {

            i = -1ULL>>(j0-48);

            if((i1&i)==0) return x;      /* x is integral */

            i>>=1;

            if((i1&i)!=0) i1 = (i1&(~i))|((0x4000000000000000LL)>>(j0-48));

        }

        SET_FLT128_WORDS64(x,i0,i1);

#ifdef USE_FENV_H

        feholdexcept (&env);

#endif

        w = TWO112[sx]+x;

        t = w-TWO112[sx];

#ifdef USE_FENV_H       

        fesetenv (&env);

#endif

        return t;

}