/* OpenCP Module Player
 * copyright (c) 1994-'10 Niklas Beisert <nbeisert@physik.tu-muenchen.de>
 * copyright (c) 2004-'26 Stian Skjelstad <stian.skjelstad@gmail.com>
 *
 * Mixer asm routines for display etc
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 * revision history: (please note changes here)
 *  -nb980510   Niklas Beisert <nbeisert@physik.tu-muenchen.de>
 *    -first release
 *  -ss04????   Stian Skjelstad <stian@nixia.no>
 *    -ported to gcc assembler
 *  -ss040908   Stian Skjelstad <stian@nixia.no>
 *    -made assembler optimizesafe
 */

#include "config.h"
#include "types.h"
#include "boot/plinkman.h"
#include "mchasm.h"

static uint16_t mean16SS(const void *ch, uint32_t len)
{
	int32_t retval=0;
	const int16_t *ref=ch;
	uint32_t l = len;

	if (!len)
	{
		return 0;
	}

	while (l)
	{
		retval += *ref;
		ref+=2;
		l--;
	}
	return retval / (int)len; /* we need a signed division */
}

uint32_t mixAddAbs16SS(const void *ch, uint32_t len)
{ /* Stereo, 16bit, signed */
	uint32_t retval=0;
	const int16_t *ref=ch;
	int16_t DCbias = mean16SS (ch, len);

	if (!len)
	{
		return 0;
	}

	while (len)
	{
		int32_t diff = (int32_t)*ref - DCbias;
		if (diff < 0)
			retval -= diff;
		else
			retval += diff;
		ref+=2;
		len--;
	}
	return retval;
}

/********************************************************************/

void mixGetMasterSampleSS16M(int16_t *_dst, const void *_src, uint32_t len, uint32_t step)
{
	uint32_t addfixed;
	uint32_t addfloat;
	uint32_t addfloatcounter;
	int16_t *src=(int16_t *)_src;
	int16_t *dst=(int16_t *)_dst;

	if (!len)
		return;
	addfloatcounter=0;
	addfloat=step&0xffff;
	addfixed=(step>>15)&0xfffe;
	do {
		*dst=(src[0]+src[1])>>1;
		src+=addfixed;
		if ((addfloatcounter+=addfloat)&0xffff0000)
		{
			addfloatcounter&=0xffff;
			src+=2;
		}
		dst+=1;
		len--;
	} while(len);
}

void mixGetMasterSampleSS16S(int16_t *_dst, const void *_src, uint32_t len, uint32_t step)
{
	uint32_t addfixed;
	uint32_t addfloat;
	uint32_t addfloatcounter;
	int16_t *src=(int16_t *)_src;
	int16_t *dst=(int16_t *)_dst;
	if (!len)
		return;
	addfloatcounter=0;
	addfloat=step&0xffff;
	addfixed=(step>>15)&0xfffe;
	do {
		dst[0]=src[0];
		dst[1]=src[1];
		src+=addfixed;
		if ((addfloatcounter+=addfloat)&0xffff0000)
		{
			addfloatcounter&=0xffff;
			src+=2;
		}
		dst+=2;
		len--;
	} while(len);
}

DLLEXTINFO_CORE_PREFIX struct linkinfostruct dllextinfo = {.name = "mchasm", .desc = "OpenCP Player Auxiliary Routines (c) 1994-'26 Niklas Beisert, Tammo Hinrichs", .ver = DLLVERSION, .sortindex = 10};
