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

95 lines
3.9 KiB
C

/***************************************************************************************
* Genesis Plus
* Mega CD / Sega CD hardware
*
* Copyright (C) 2012-2014 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 _HW_SCD_
#define _HW_SCD_
#include "cdd.h"
#include "cdc.h"
#include "gfx.h"
#include "pcm.h"
#include "cd_cart.h"
#ifdef USE_DYNAMIC_ALLOC
#define scd ext->cd_hw
#else
#define scd ext.cd_hw
#endif
/* 5000000 SCD clocks/s = ~3184 clocks/line with a Master Clock of 53.693175 MHz */
/* This would be slightly (~30 clocks) more on PAL systems because of the slower */
/* Master Clock (53.203424 MHz) but not enough to really care about since clocks */
/* are not running in sync anyway. */
#define SCD_CLOCK 50000000
#define SCYCLES_PER_LINE 3184
/* Timer & Stopwatch clocks divider */
#define TIMERS_SCYCLES_RATIO (384 * 4)
/* CD hardware */
typedef struct
{
cd_cart_t cartridge; /* ROM/RAM Cartridge */
uint8 bootrom[0x20000]; /* 128K internal BOOT ROM */
uint8 prg_ram[0x80000]; /* 512K PRG-RAM */
uint8 word_ram[2][0x20000]; /* 2 x 128K Word RAM (1M mode) */
uint8 word_ram_2M[0x40000]; /* 256K Word RAM (2M mode) */
uint8 bram[0x2000]; /* 8K Backup RAM */
reg16_t regs[0x100]; /* 256 x 16-bit ASIC registers */
uint32 cycles; /* Master clock counter */
int32 stopwatch; /* Stopwatch counter */
int32 timer; /* Timer counter */
uint8 pending; /* Pending interrupts */
uint8 dmna; /* Pending DMNA write status */
gfx_t gfx_hw; /* Graphics processor */
cdc_t cdc_hw; /* CD data controller */
cdd_t cdd_hw; /* CD drive processor */
pcm_t pcm_hw; /* PCM chip */
} cd_hw_t;
/* Function prototypes */
extern void scd_init(void);
extern void scd_reset(int hard);
extern void scd_update(unsigned int cycles);
extern void scd_end_frame(unsigned int cycles);
extern int scd_context_load(uint8 *state);
extern int scd_context_save(uint8 *state);
extern int scd_68k_irq_ack(int level);
extern void prg_ram_dma_w(unsigned int words);
#endif