/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002  Sam Lantinga

    This library is free software; you can redistribute it and/or

    modify it under the terms of the GNU Library General Public

    License as published by the Free Software Foundation; either

    version 2 of the License, or (at your option) any later version.

    This library 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

    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public

    License along with this library; if not, write to the Free

    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Sam Lantinga

    slouken@libsdl.org

*/

/*

	m68k assembly mix routines

	Patrice Mandin

*/

#if defined(__M68000__) && defined(__GNUC__)

void SDL_MixAudio_m68k_U8(char* dst, char* src, long len, long volume, char* mix8)

{

    __asm__ __volatile__ (

	"tstl	%2\n"

"	beqs	stoploop_u8\n"

"mixloop_u8:\n"

	/* Mix a sample */

"	moveq	#0,%%d0\n"

"	moveq	#0,%%d1\n"

"	moveb	%1@+,%%d0\n"	/* d0 = *src++ */

"	sub	#128,%%d0\n"	/* d0 -= 128 */

"	muls	%3,%%d0\n"	/* d0 *= volume (0<=volume<=128) */

"	moveb	%0@,%%d1\n"	/* d1 = *dst */

"	asr	#7,%%d0\n"	/* d0 /= 128 (SDL_MIX_MAXVOLUME) */

"	add	#128,%%d0\n"	/* d0 += 128 */

"	add	%%d1,%%d0\n"

"	moveb	%4@(%%d0:w),%0@+\n"

	/* Loop till done */

"	subql	#1,%2\n"

"	bhis	mixloop_u8\n"

"stoploop_u8:\n"

	 : /* no return value */

	 : /* input */

	 	"a"(dst), "a"(src), "d"(len), "d"(volume), "a"(mix8)	

	 : /* clobbered registers */

	 	"d0", "d1", "cc", "memory" 

	 );

}

void SDL_MixAudio_m68k_S8(char* dst, char* src, long len, long volume)

{

    __asm__ __volatile__ (

	"tstl	%2\n"

"	beqs	stoploop_s8\n"

"	moveq	#-128,%%d2\n"

"	moveq	#127,%%d3\n"

"mixloop_s8:\n"

	/* Mix a sample */

"	moveq	#0,%%d0\n"

"	moveq	#0,%%d1\n"

"	moveb	%1@+,%%d0\n"	/* d0 = *src++ */

"	muls	%3,%%d0\n"	/* d0 *= volume (0<=volume<=128) */

"	moveb	%0@,%%d1\n"	/* d1 = *dst */

"	asr	#7,%%d0\n"	/* d0 /= 128 (SDL_MIX_MAXVOLUME) */

"	add	%%d1,%%d0\n"

"	cmp	%%d2,%%d0\n"

"	bges	lower_limit_s8\n"

"	move	%%d2,%%d0\n"

"lower_limit_s8:\n"

"	cmp	%%d3,%%d0\n"

"	bles	upper_limit_s8\n"

"	move	%%d3,%%d0\n"

"upper_limit_s8:\n"

"	moveb	%%d0,%0@+\n"

	/* Loop till done */

"	subql	#1,%2\n"

"	bhis	mixloop_s8\n"

"stoploop_s8:\n"

	 : /* no return value */

	 : /* input */

	 	"a"(dst), "a"(src), "d"(len), "d"(volume)	

	 : /* clobbered registers */

	 	"d0", "d1", "d2", "d3", "cc", "memory" 

	 );

}

void SDL_MixAudio_m68k_S16MSB(short* dst, short* src, long len, long volume)

{

    __asm__ __volatile__ (

	"tstl	%2\n"

"	beqs	stoploop_s16msb\n"

"	movel	#-32768,%%d2\n"

"	movel	#32767,%%d3\n"

"	lsrl	#1,%2\n"

"mixloop_s16msb:\n"

	/* Mix a sample */

"	move	%1@+,%%d0\n"	/* d0 = *src++ */

"	muls	%3,%%d0\n"	/* d0 *= volume (0<=volume<=128) */

"	move	%0@,%%d1\n"	/* d1 = *dst */

"	extl	%%d1\n"		/* extend d1 to 32 bits */

"	asrl	#7,%%d0\n"	/* d0 /= 128 (SDL_MIX_MAXVOLUME) */

"	addl	%%d1,%%d0\n"

"	cmpl	%%d2,%%d0\n"

"	bges	lower_limit_s16msb\n"

"	move	%%d2,%%d0\n"

"lower_limit_s16msb:\n"

"	cmpl	%%d3,%%d0\n"

"	bles	upper_limit_s16msb\n"

"	move	%%d3,%%d0\n"

"upper_limit_s16msb:\n"

"	move	%%d0,%0@+\n"

	/* Loop till done */

"	subql	#1,%2\n"

"	bhis	mixloop_s16msb\n"

"stoploop_s16msb:\n"

	 : /* no return value */

	 : /* input */

	 	"a"(dst), "a"(src), "d"(len), "d"(volume)	

	 : /* clobbered registers */

	 	"d0", "d1", "d2", "d3", "cc", "memory" 

	 );

}

void SDL_MixAudio_m68k_S16LSB(short* dst, short* src, long len, long volume)

{

    __asm__ __volatile__ (

	"tstl	%2\n"

"	beqs	stoploop_s16lsb\n"

"	movel	#-32768,%%d2\n"

"	movel	#32767,%%d3\n"

"	lsrl	#1,%2\n"

"mixloop_s16lsb:\n"

	/* Mix a sample */

"	move	%1@+,%%d0\n"	/* d0 = *src++ */

"	rorw	#8,%%d0\n"

"	muls	%3,%%d0\n"	/* d0 *= volume (0<=volume<=128) */

"	move	%0@,%%d1\n"	/* d1 = *dst */

"	rorw	#8,%%d1\n"

"	extl	%%d1\n"		/* extend d1 to 32 bits */

"	asrl	#7,%%d0\n"	/* d0 /= 128 (SDL_MIX_MAXVOLUME) */

"	addl	%%d1,%%d0\n"

"	cmpl	%%d2,%%d0\n"

"	bges	lower_limit_s16lsb\n"

"	move	%%d2,%%d0\n"

"lower_limit_s16lsb:\n"

"	cmpl	%%d3,%%d0\n"

"	bles	upper_limit_s16lsb\n"

"	move	%%d3,%%d0\n"

"upper_limit_s16lsb:\n"

"	rorw	#8,%%d0\n"

"	move	%%d0,%0@+\n"

	/* Loop till done */

"	subql	#1,%2\n"

"	bhis	mixloop_s16lsb\n"

"stoploop_s16lsb:\n"

	 : /* no return value */

	 : /* input */

	 	"a"(dst), "a"(src), "d"(len), "d"(volume)	

	 : /* clobbered registers */

	 	"d0", "d1", "d2", "d3", "cc", "memory" 

	 );

}

#endif