src/audio/SDL_mixer_m68k.c
author Sam Lantinga <slouken@libsdl.org>
Sun, 28 May 2006 13:04:16 +0000
branchSDL-1.3
changeset 1662 782fd950bd46
parent 1402 d910939febfa
child 1668 4da1ee79c9af
permissions -rw-r--r--
Revamp of the video system in progress - adding support for multiple displays, multiple windows, and a full video mode selection API. WARNING: None of the video drivers have been updated for the new API yet! The API is still under design and very fluid. The code is now run through a consistent indent format: indent -i4 -nut -nsc -br -ce The headers are being converted to automatically generate doxygen documentation.

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2004 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
*/
#include "SDL_config.h"

/*
	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
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