Genesis-Plus-GX/core/cd_hw/pcm.h

78 lines
3.3 KiB
C

/***************************************************************************************
* Genesis Plus
* PCM sound chip (315-5476A) (RF5C164 compatible)
*
* Copyright (C) 2012 Eke-Eke (Genesis Plus GX)
*
* Redistribution and use of this code or any derivative works are permitted
* provided that the following conditions are met:
*
* - Redistributions may not be sold, nor may they be used in a commercial
* product or activity.
*
* - Redistributions that are modified from the original source must include the
* complete source code, including the source code for all components used by a
* binary built from the modified sources. However, as a special exception, the
* source code distributed need not include anything that is normally distributed
* (in either source or binary form) with the major components (compiler, kernel,
* and so on) of the operating system on which the executable runs, unless that
* component itself accompanies the executable.
*
* - Redistributions must reproduce the above copyright notice, this list of
* conditions and the following disclaimer in the documentation and/or other
* materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************************/
#ifndef _CD_PCM_
#define _CD_PCM_
#include "blip_buf.h"
/* PCM channel */
typedef struct
{
uint32 addr; /* current Wave RAM address (16.11 fixed point) */
uint32 st; /* Wave RAM start address (16.11 fixed point) */
reg16_t ls; /* Wave RAM loop address ($0000-$ffff) */
reg16_t fd; /* Wave RAM address increment (5.11 fixed point) */
uint8 env; /* enveloppe multiplier */
uint8 pan; /* stereo panning */
} chan_t;
/* PCM sound chip */
typedef struct
{
chan_t chan[8]; /* PCM channels 1-8 */
int16 out[2]; /* previous PCM stereo output */
uint8 *bank; /* external RAM bank pointer */
uint8 enabled; /* PCM chip ON/OFF status */
uint8 status; /* channels ON/OFF status */
uint8 index; /* current channel index */
uint8 ram[0x10000]; /* 64k external RAM */
uint32 cycles;
} pcm_t;
/* Function prototypes */
extern void pcm_init(blip_t* left, blip_t* right);
extern void pcm_reset(void);
extern int pcm_context_save(uint8 *state);
extern int pcm_context_load(uint8 *state);
extern void pcm_update(unsigned int samples);
extern void pcm_write(unsigned int address, unsigned char data);
extern unsigned char pcm_read(unsigned int address);
extern void pcm_ram_dma_w(unsigned int words);
#endif