/*
 * libmad - MPEG audio decoder library
 * Copyright (C) 2000-2004 Underbit Technologies, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * $Id: fixed.c,v 1.13 2004/01/23 09:41:32 rob Exp $
 */

#ifdef HAVE_CONFIG_H
  #include "config.h"
#endif

#include "fixed.h"
#include "global.h"

/*
 * NAME:	fixed->abs()
 * DESCRIPTION:	return absolute value of a fixed-point number
 */
mad_fixed_t mad_f_abs(mad_fixed_t x) { return x < 0 ? -x : x; }

/*
 * NAME:	fixed->div()
 * DESCRIPTION:	perform division using fixed-point math
 */
mad_fixed_t mad_f_div(mad_fixed_t x, mad_fixed_t y)
{
	mad_fixed_t	 q, r;
	unsigned int bits;

	q = mad_f_abs(x / y);

	if (x < 0)
	{
		x = -x;
		y = -y;
	}

	r = x % y;

	if (y < 0)
	{
		x = -x;
		y = -y;
	}

	if (q > mad_f_intpart(MAD_F_MAX) && !(q == -mad_f_intpart(MAD_F_MIN) && r == 0 && (x < 0) != (y < 0))) return 0;

	for (bits = MAD_F_FRACBITS; bits && r; --bits)
	{
		q <<= 1, r <<= 1;
		if (r >= y) r -= y, ++q;
	}

	/* round */
	if (2 * r >= y) ++q;

	/* fix sign */
	if ((x < 0) != (y < 0)) q = -q;

	return q << bits;
}