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https://github.com/ekeeke/Genesis-Plus-GX.git
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91 lines
3.9 KiB
C
91 lines
3.9 KiB
C
/***************************************************************************************
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* Genesis Plus
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* Mega CD / Sega CD hardware
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*
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* Copyright (C) 2012-2013 Eke-Eke (Genesis Plus GX)
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*
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* Redistribution and use of this code or any derivative works are permitted
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* provided that the following conditions are met:
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*
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* - Redistributions may not be sold, nor may they be used in a commercial
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* product or activity.
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*
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* - Redistributions that are modified from the original source must include the
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* complete source code, including the source code for all components used by a
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* binary built from the modified sources. However, as a special exception, the
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* source code distributed need not include anything that is normally distributed
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* (in either source or binary form) with the major components (compiler, kernel,
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* and so on) of the operating system on which the executable runs, unless that
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* component itself accompanies the executable.
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*
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* - Redistributions must reproduce the above copyright notice, this list of
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* conditions and the following disclaimer in the documentation and/or other
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* materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************************/
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#ifndef _HW_SCD_
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#define _HW_SCD_
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#include "cdd.h"
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#include "cdc.h"
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#include "gfx.h"
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#include "pcm.h"
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#include "cd_cart.h"
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#define scd ext.cd_hw
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/* 5000000 SCD clocks/s = ~3184 clocks/line with a Master Clock of 53.693175 MHz */
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/* This would be slightly (~30 clocks) more on PAL systems because of the slower */
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/* Master Clock (53.203424 MHz) but not enough to really care about since clocks */
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/* are not running in sync anyway. */
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#define SCD_CLOCK 50000000
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#define SCYCLES_PER_LINE 3184
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/* Timer & Stopwatch clocks divider */
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#define TIMERS_SCYCLES_RATIO (384 * 4)
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/* CD hardware */
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typedef struct
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{
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cd_cart_t cartridge; /* ROM/RAM Cartridge */
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uint8 bootrom[0x20000]; /* 128K internal BOOT ROM */
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uint8 prg_ram[0x80000]; /* 512K PRG-RAM */
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uint8 word_ram[2][0x20000]; /* 2 x 128K Word RAM (1M mode) */
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uint8 word_ram_2M[0x40000]; /* 256K Word RAM (2M mode) */
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uint8 bram[0x2000]; /* 8K Backup RAM */
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reg16_t regs[0x100]; /* 256 x 16-bit ASIC registers */
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uint32 cycles; /* Master clock counter */
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int32 stopwatch; /* Stopwatch counter */
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int32 timer; /* Timer counter */
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uint8 pending; /* Pending interrupts */
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uint8 dmna; /* Pending DMNA write status */
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gfx_t gfx_hw; /* Graphics processor */
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cdc_t cdc_hw; /* CD data controller */
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cdd_t cdd_hw; /* CD drive processor */
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pcm_t pcm_hw; /* PCM chip */
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} cd_hw_t;
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/* Function prototypes */
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extern void scd_init(void);
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extern void scd_reset(int hard);
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extern void scd_update(unsigned int cycles);
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extern void scd_end_frame(unsigned int cycles);
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extern int scd_context_load(uint8 *state);
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extern int scd_context_save(uint8 *state);
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extern int scd_68k_irq_ack(int level);
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extern void prg_ram_dma_w(unsigned int words);
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#endif
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