/* @(#)s_floor.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.

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

 */

//__FBSDID("$FreeBSD: src/lib/msun/src/s_trunc.c,v 1.4 2008/02/22 02:27:34 das Exp $");

/*

 * trunc(x)

 * Return x rounded toward 0 to integral value

 * Method:

 *  Bit twiddling.

 * Exception:

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

 */

#include "math_private.h"

static const double huge = 1.0e300;

double

s_trunc(double x)

{

  int32_t i0,i1,j0;

  u_int32_t i;

  EXTRACT_WORDS(i0,i1,x);

  j0 = ((i0>>20)&0x7ff)-0x3ff;

  if(j0<20) {

      if(j0<0) {   /* raise inexact if x != 0 */

    if(huge+x>0.0) {/* |x|<1, so return 0*sign(x) */

        i0 &= 0x80000000U;

        i1 = 0;

    }

      } else {

    i = (0x000fffff)>>j0;

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

    if(huge+x>0.0) { /* raise inexact flag */

        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 */

      if(huge+x>0.0)   /* raise inexact flag */

    i1 &= (~i);

  }

  INSERT_WORDS(x,i0,i1);

  return x;

}