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

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/***************************************************************************************
* Genesis Plus
* Mega CD / Sega CD hardware
*
* Copyright (C) 2012-2024 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.
*
****************************************************************************************/
#include "shared.h"
/*--------------------------------------------------------------------------*/
/* Unused area (return open bus data, i.e prefetched instruction word) */
/*--------------------------------------------------------------------------*/
static unsigned int s68k_read_bus_8(unsigned int address)
{
#ifdef LOGERROR
error("[SUB 68k] Unused read8 %08X (%08X)\n", address, s68k.pc);
#endif
address = s68k.pc | (address & 1);
return READ_BYTE(s68k.memory_map[((address)>>16)&0xff].base, (address) & 0xffff);
}
static unsigned int s68k_read_bus_16(unsigned int address)
{
#ifdef LOGERROR
error("[SUB 68k] Unused read16 %08X (%08X)\n", address, s68k.pc);
#endif
address = s68k.pc;
return *(uint16 *)(s68k.memory_map[((address)>>16)&0xff].base + ((address) & 0xffff));
}
static void s68k_unused_8_w(unsigned int address, unsigned int data)
{
#ifdef LOGERROR
error("[SUB 68k] Unused write8 %08X = %02X (%08X)\n", address, data, s68k.pc);
#endif
}
static void s68k_unused_16_w(unsigned int address, unsigned int data)
{
#ifdef LOGERROR
error("[SUB 68k] Unused write16 %08X = %04X (%08X)\n", address, data, s68k.pc);
#endif
}
/*--------------------------------------------------------------------------*/
/* Locked area (cause SUB-CPU to wait for /DTACK assertion) */
/*--------------------------------------------------------------------------*/
static void s68k_lockup_w_8 (unsigned int address, unsigned int data)
{
#ifdef LOGERROR
error ("[SUB 68k] Lockup write8 %08X = %02X (%08X)\n", address, data, s68k.pc);
#endif
s68k_pulse_wait(address, 1);
}
static void s68k_lockup_w_16 (unsigned int address, unsigned int data)
{
#ifdef LOGERROR
error ("[SUB 68k] Lockup write16 %08X = %04X (%08X)\n", address, data, s68k.pc);
#endif
s68k_pulse_wait(address, 1);
}
static unsigned int s68k_lockup_r_8 (unsigned int address)
{
#ifdef LOGERROR
error ("[SUB 68k] Lockup read8 %08X.b (%08X)\n", address, s68k.pc);
#endif
s68k_pulse_wait(address, 0);
return 0xff;
}
static unsigned int s68k_lockup_r_16 (unsigned int address)
{
#ifdef LOGERROR
error ("[SUB 68k] Lockup read16 %08X.w (%08X)\n", address, s68k.pc);
#endif
s68k_pulse_wait(address, 0);
return 0xffff;
}
/*--------------------------------------------------------------------------*/
/* PRG-RAM DMA access */
/*--------------------------------------------------------------------------*/
void prg_ram_dma_w(unsigned int length)
{
uint16 data;
/* 16-bit DMA only */
unsigned int words = length >> 1;
/* CDC buffer source address */
uint16 src_index = cdc.dac.w & 0x3ffe;
/* PRG-RAM destination address*/
uint32 dst_index = (scd.regs[0x0a>>1].w << 3) & 0x7fffe;
/* update DMA destination address */
scd.regs[0x0a>>1].w += (words >> 2);
/* update DMA source address */
cdc.dac.w += (words << 1);
/* DMA transfer */
while (words--)
{
/* read 16-bit word from CDC RAM buffer (big-endian format) */
data = READ_WORD(cdc.ram, src_index);
/* write 16-bit word to PRG-RAM */
*(uint16 *)(scd.prg_ram + dst_index) = data ;
/* increment CDC buffer source address */
src_index = (src_index + 2) & 0x3ffe;
/* increment PRG-RAM destination address */
dst_index = (dst_index + 2) & 0x7fffe;
}
}
/*--------------------------------------------------------------------------*/
/* PRG-RAM write protected area */
/*--------------------------------------------------------------------------*/
static void prg_ram_write_byte(unsigned int address, unsigned int data)
{
address &= 0x7ffff;
if (address >= (scd.regs[0x02>>1].byte.h << 9))
{
WRITE_BYTE(scd.prg_ram, address, data);
return;
}
#ifdef LOGERROR
error("[SUB 68k] PRG-RAM protected write8 %08X = %02X (%08X)\n", address, data, s68k.pc);
#endif
}
static void prg_ram_write_word(unsigned int address, unsigned int data)
{
address &= 0x7fffe;
if (address >= (scd.regs[0x02>>1].byte.h << 9))
{
*(uint16 *)(scd.prg_ram + address) = data;
return;
}
#ifdef LOGERROR
error("[SUB 68k] PRG-RAM protected write16 %08X = %02X (%08X)\n", address, data, s68k.pc);
#endif
}
/*--------------------------------------------------------------------------*/
/* PRG-RAM bank mirrored access */
/*--------------------------------------------------------------------------*/
static unsigned int prg_ram_z80_read_byte(unsigned int address)
{
int offset = (address >> 16) & 0x03;
if (zbank_memory_map[offset].read)
{
return zbank_memory_map[offset].read(address);
}
return READ_BYTE(m68k.memory_map[offset].base, address & 0xffff);
}
static void prg_ram_z80_write_byte(unsigned int address, unsigned int data)
{
int offset = (address >> 16) & 0x03;
if (zbank_memory_map[offset].write)
{
zbank_memory_map[offset].write(address, data);
}
else
{
WRITE_BYTE(m68k.memory_map[offset].base, address & 0xffff, data);
}
}
static unsigned int prg_ram_m68k_read_byte(unsigned int address)
{
int offset = (address >> 16) & 0x03;
if (m68k.memory_map[offset].read8)
{
return m68k.memory_map[offset].read8(address);
}
return READ_BYTE(m68k.memory_map[offset].base, address & 0xffff);
}
static unsigned int prg_ram_m68k_read_word(unsigned int address)
{
int offset = (address >> 16) & 0x03;
if (m68k.memory_map[offset].read16)
{
return m68k.memory_map[offset].read16(address);
}
return *(uint16 *)(m68k.memory_map[offset].base + (address & 0xffff));
}
static void prg_ram_m68k_write_byte(unsigned int address, unsigned int data)
{
int offset = (address >> 16) & 0x03;
if (m68k.memory_map[offset].write8)
{
m68k.memory_map[offset].write8(address, data);
}
else
{
WRITE_BYTE(m68k.memory_map[offset].base, address & 0xffff, data);
}
}
static void prg_ram_m68k_write_word(unsigned int address, unsigned int data)
{
int offset = (address >> 16) & 0x03;
if (m68k.memory_map[offset].write16)
{
m68k.memory_map[offset].write16(address, data);
}
else
{
*(uint16 *)(m68k.memory_map[offset].base + (address & 0xffff)) = data;
}
}
/*--------------------------------------------------------------------------*/
/* Word-RAM bank mirrored access */
/*--------------------------------------------------------------------------*/
static unsigned int word_ram_z80_read_byte(unsigned int address)
{
int offset = (address >> 16) & 0x23;
if (zbank_memory_map[offset].read)
{
return zbank_memory_map[offset].read(address);
}
return READ_BYTE(m68k.memory_map[offset].base, address & 0xffff);
}
static void word_ram_z80_write_byte(unsigned int address, unsigned int data)
{
int offset = (address >> 16) & 0x23;
if (zbank_memory_map[offset].write)
{
zbank_memory_map[offset].write(address, data);
}
else
{
*(uint16 *)(m68k.memory_map[offset].base + (address & 0xfffe)) = data | (data << 8);
}
}
static unsigned int word_ram_m68k_read_byte(unsigned int address)
{
int offset = (address >> 16) & 0x23;
if (m68k.memory_map[offset].read8)
{
return m68k.memory_map[offset].read8(address);
}
return READ_BYTE(m68k.memory_map[offset].base, address & 0xffff);
}
static unsigned int word_ram_m68k_read_word(unsigned int address)
{
int offset = (address >> 16) & 0x23;
if (m68k.memory_map[offset].read16)
{
return m68k.memory_map[offset].read16(address);
}
return *(uint16 *)(m68k.memory_map[offset].base + (address & 0xffff));
}
static void word_ram_m68k_write_byte(unsigned int address, unsigned int data)
{
int offset = (address >> 16) & 0x23;
if (m68k.memory_map[offset].write8)
{
m68k.memory_map[offset].write8(address, data);
}
else
{
*(uint16 *)(m68k.memory_map[offset].base + (address & 0xfffe)) = data | (data << 8);
}
}
static void word_ram_m68k_write_word(unsigned int address, unsigned int data)
{
int offset = (address >> 16) & 0x23;
if (m68k.memory_map[offset].write16)
{
m68k.memory_map[offset].write16(address, data);
}
else
{
*(uint16 *)(m68k.memory_map[offset].base + (address & 0xffff)) = data;
}
}
static unsigned int word_ram_s68k_read_byte(unsigned int address)
{
int offset = (address >> 16) & 0x0f;
if (s68k.memory_map[offset].read8)
{
return s68k.memory_map[offset].read8(address);
}
return READ_BYTE(s68k.memory_map[offset].base, address & 0xffff);
}
static unsigned int word_ram_s68k_read_word(unsigned int address)
{
int offset = (address >> 16) & 0x0f;
if (s68k.memory_map[offset].read16)
{
return s68k.memory_map[offset].read16(address);
}
return *(uint16 *)(s68k.memory_map[offset].base + (address & 0xffff));
}
static void word_ram_s68k_write_byte(unsigned int address, unsigned int data)
{
int offset = (address >> 16) & 0x0f;
if (s68k.memory_map[offset].write8)
{
s68k.memory_map[offset].write8(address, data);
}
else
{
*(uint16 *)(s68k.memory_map[offset].base + (address & 0xfffe)) = data | (data << 8);
}
}
static void word_ram_s68k_write_word(unsigned int address, unsigned int data)
{
int offset = (address >> 16) & 0x0f;
if (s68k.memory_map[offset].write16)
{
s68k.memory_map[offset].write16(address, data);
}
else
{
*(uint16 *)(s68k.memory_map[offset].base + (address & 0xffff)) = data;
}
}
/*--------------------------------------------------------------------------*/
/* internal backup RAM (8KB) */
/*--------------------------------------------------------------------------*/
static unsigned int bram_read_byte(unsigned int address)
{
/* LSB only */
if (address & 0x01)
{
return scd.bram[(address >> 1) & 0x1fff];
}
return 0xff;
}
static unsigned int bram_read_word(unsigned int address)
{
return (scd.bram[(address >> 1) & 0x1fff] | 0xff00);
}
static void bram_write_byte(unsigned int address, unsigned int data)
{
/* LSB only */
if (address & 0x01)
{
scd.bram[(address >> 1) & 0x1fff] = data;
}
}
static void bram_write_word(unsigned int address, unsigned int data)
{
scd.bram[(address >> 1) & 0x1fff] = data & 0xff;
}
/*--------------------------------------------------------------------------*/
/* SUB-CPU polling detection and MAIN-CPU synchronization */
/*--------------------------------------------------------------------------*/
static void s68k_poll_detect(unsigned int reg_mask)
{
/* detect SUB-CPU register polling */
if (s68k.poll.detected & reg_mask)
{
if (s68k.cycles <= s68k.poll.cycle)
{
if (s68k.pc == s68k.poll.pc)
{
/* SUB-CPU polling confirmed ? */
if (s68k.poll.detected & 1)
{
/* idle SUB-CPU until register is modified */
#ifdef LOG_SCD
error("s68k stopped from %d cycles\n", s68k.cycles);
#endif
s68k.cycles = s68k.cycle_end;
s68k.stopped = reg_mask;
}
else
{
/* confirm SUB-CPU polling */
s68k.poll.detected |= 1;
s68k.poll.cycle = s68k.cycles + 392;
}
}
return;
}
}
else
{
/* set SUB-CPU register access flag */
s68k.poll.detected = reg_mask;
}
/* reset SUB-CPU polling detection */
s68k.poll.cycle = s68k.cycles + 392;
s68k.poll.pc = s68k.pc;
}
static void s68k_poll_sync(unsigned int reg_mask)
{
/* relative MAIN-CPU cycle counter */
unsigned int cycles = (s68k.cycles * MCYCLES_PER_LINE) / SCYCLES_PER_LINE;
if (!m68k.stopped)
{
/* save current MAIN-CPU end cycle count (recursive execution is possible) */
int end_cycle = m68k.cycle_end;
/* sync MAIN-CPU with SUB-CPU */
m68k_run(cycles);
/* restore MAIN-CPU end cycle count */
m68k.cycle_end = end_cycle;
}
/* MAIN-CPU idle on register polling ? */
if (m68k.stopped & reg_mask)
{
/* sync MAIN-CPU with SUB-CPU */
m68k.cycles = cycles;
/* restart MAIN-CPU */
m68k.stopped = 0;
#ifdef LOG_SCD
error("m68k started from %d cycles\n", cycles);
#endif
}
/* clear CPU register access flags */
s68k.poll.detected &= ~reg_mask;
m68k.poll.detected &= ~reg_mask;
}
static void m68k_sync(void)
{
if (!m68k.stopped)
{
/* relative MAIN-CPU cycle counter */
unsigned int cycles = (s68k.cycles * MCYCLES_PER_LINE) / SCYCLES_PER_LINE;
/* save current MAIN-CPU end cycle count (recursive execution is possible) */
int end_cycle = m68k.cycle_end;
/* sync MAIN-CPU with SUB-CPU */
m68k_run(cycles);
/* restore MAIN-CPU end cycle count */
m68k.cycle_end = end_cycle;
}
}
/*--------------------------------------------------------------------------*/
/* PCM chip & Gate-Array area */
/*--------------------------------------------------------------------------*/
static unsigned int scd_read_byte(unsigned int address)
{
/* PCM area (8K) mirrored into $xF0000-$xF7FFF */
if (!(address & 0x8000))
{
/* get /LDS only */
if (address & 1)
{
return pcm_read((address >> 1) & 0x1fff, s68k.cycles);
}
return s68k_read_bus_8(address);
}
#ifdef LOG_SCD
error("[%d][%d]read byte CD register %X (%X)\n", v_counter, s68k.cycles, address, s68k.pc);
#endif
/* only A1-A8 are used for decoding */
address &= 0x1ff;
/* Memory Mode */
if (address == 0x03)
{
s68k_poll_detect(1<<0x03);
/* mask BK0 and BK1 bits on SUB-CPU side */
return scd.regs[0x03>>1].byte.l & 0x1f;
}
/* MAIN-CPU communication flags */
if (address == 0x0e)
{
s68k_poll_detect(1<<0x0e);
return scd.regs[0x0e>>1].byte.h;
}
/* CDC transfer status */
if (address == 0x04)
{
s68k_poll_detect(1<<0x04);
return scd.regs[0x04>>1].byte.h;
}
/* GFX operation status */
if (address == 0x58)
{
s68k_poll_detect(1<<0x08);
return scd.regs[0x58>>1].byte.h;
}
/* CDC register data */
if (address == 0x07)
{
return cdc_reg_r();
}
/* LED status */
if (address == 0x00)
{
/* register $00 is reserved for MAIN-CPU, we use $06 instead */
return scd.regs[0x06>>1].byte.h;
}
/* RESET status */
if (address == 0x01)
{
/* always return 1 */
return 0x01;
}
/* Font data */
if ((address >= 0x50) && (address <= 0x57))
{
/* shifted 4-bit input (xxxx00) */
uint8 bits = (scd.regs[0x4e>>1].w >> (((address & 6) ^ 6) << 1)) << 2;
/* color code */
uint8 code = scd.regs[0x4c>>1].byte.l;
/* 16-bit font data (4 pixels = 16 bits) */
uint16 data = (code >> (bits & 4)) & 0x0f;
bits = bits >> 1;
data = data | (((code >> (bits & 4)) << 4) & 0xf0);
bits = bits >> 1;
data = data | (((code >> (bits & 4)) << 8) & 0xf00);
bits = bits >> 1;
data = data | (((code >> (bits & 4)) << 12) & 0xf000);
return (address & 1) ? (data & 0xff) : (data >> 8);
}
/* MAIN-CPU communication words */
if ((address & 0x1f0) == 0x10)
{
s68k_poll_detect(1 << (address & 0x1f));
}
/* Subcode buffer */
else if (address & 0x100)
{
/* 64 x 16-bit mirrored */
address &= 0x17f;
}
/* default registers */
if (address & 1)
{
/* register LSB */
return scd.regs[address >> 1].byte.l;
}
/* register MSB */
return scd.regs[address >> 1].byte.h;
}
static unsigned int scd_read_word(unsigned int address)
{
/* PCM area (8K) mirrored into $xF0000-$xF7FFF */
if (!(address & 0x8000))
{
/* get /LDS only */
return pcm_read((address >> 1) & 0x1fff, s68k.cycles);
}
#ifdef LOG_SCD
error("[%d][%d]read word CD register %X (%X)\n", v_counter, s68k.cycles, address, s68k.pc);
#endif
/* only A1-A8 are used for decoding */
address &= 0x1ff;
/* Memory Mode */
if (address == 0x02)
{
s68k_poll_detect(1<<0x03);
/* mask BK0 and BK1 bits on SUB-CPU side */
return scd.regs[0x03>>1].w & 0xff1f;
}
/* CDC host data (word access only ?) */
if (address == 0x08)
{
return cdc_host_r(CDC_SUB_CPU_ACCESS);
}
/* LED & RESET status */
if (address == 0x00)
{
/* register $00 is reserved for MAIN-CPU, we use $06 instead */
return scd.regs[0x06>>1].w;
}
/* Stopwatch counter (word access only ?) */
if (address == 0x0c)
{
/* cycle-accurate counter value */
return (scd.regs[0x0c>>1].w + ((s68k.cycles - scd.stopwatch) / TIMERS_SCYCLES_RATIO)) & 0xfff;
}
/* Font data */
if ((address >= 0x50) && (address <= 0x56))
{
/* shifted 4-bit input (xxxx00) */
uint8 bits = (scd.regs[0x4e>>1].w >> (((address & 6) ^ 6) << 1)) << 2;
/* color code */
uint8 code = scd.regs[0x4c>>1].byte.l;
/* 16-bit font data (4 pixels = 16 bits) */
uint16 data = (code >> (bits & 4)) & 0x0f;
bits = bits >> 1;
data = data | (((code >> (bits & 4)) << 4) & 0xf0);
bits = bits >> 1;
data = data | (((code >> (bits & 4)) << 8) & 0xf00);
bits = bits >> 1;
data = data | (((code >> (bits & 4)) << 12) & 0xf000);
return data;
}
/* CDC register data */
if (address == 0x06)
{
return cdc_reg_r();
}
/* MAIN-CPU communication words */
if ((address & 0x1f0) == 0x10)
{
/* sync MAIN-CPU with SUB-CPU (fixes Mighty Morphin Power Rangers) */
m68k_sync();
s68k_poll_detect(3 << (address & 0x1e));
}
/* Subcode buffer */
else if (address & 0x100)
{
/* 64 x 16-bit mirrored */
address &= 0x17f;
}
/* default registers */
return scd.regs[address >> 1].w;
}
INLINE void word_ram_switch(uint8 mode)
{
int i;
uint16 *ptr1 = (uint16 *)(scd.word_ram_2M);
uint16 *ptr2 = (uint16 *)(scd.word_ram[0]);
uint16 *ptr3 = (uint16 *)(scd.word_ram[1]);
if (mode & 0x04)
{
/* 2M -> 1M mode */
for (i=0; i<0x10000; i++)
{
*ptr2++=*ptr1++;
*ptr3++=*ptr1++;
}
/* MAIN-CPU: $200000-$21FFFF is mapped to Word-RAM 0 or 1 */
for (i=scd.cartridge.boot+0x20; i<scd.cartridge.boot+0x22; i++)
{
m68k.memory_map[i].read8 = NULL;
m68k.memory_map[i].read16 = NULL;
m68k.memory_map[i].write8 = NULL;
m68k.memory_map[i].write16 = NULL;
zbank_memory_map[i].read = NULL;
zbank_memory_map[i].write = NULL;
}
/* SUB-CPU: $0C0000-$0DFFFF is mapped to Word-RAM 0 or 1 */
for (i=0x0c; i<0x0e; i++)
{
s68k.memory_map[i].read8 = NULL;
s68k.memory_map[i].read16 = NULL;
s68k.memory_map[i].write8 = NULL;
s68k.memory_map[i].write16 = NULL;
}
}
else
{
/* 1M -> 2M mode */
for (i=0; i<0x10000; i++)
{
*ptr1++=*ptr2++;
*ptr1++=*ptr3++;
}
/* MAIN-CPU: $200000-$21FFFF is mapped to 256K Word-RAM (lower 128K) */
for (i=scd.cartridge.boot+0x20; i<scd.cartridge.boot+0x22; i++)
{
m68k.memory_map[i].base = scd.word_ram_2M + ((i & 0x03) << 16);
}
/* SUB-CPU: $0C0000-$0DFFFF is unmapped */
for (i=0x0c; i<0x0e; i++)
{
s68k.memory_map[i].read8 = s68k_read_bus_8;
s68k.memory_map[i].read16 = s68k_read_bus_16;
s68k.memory_map[i].write8 = s68k_unused_8_w;
s68k.memory_map[i].write16 = s68k_unused_16_w;
}
}
}
static void scd_write_word(unsigned int address, unsigned int data);
static void scd_write_byte(unsigned int address, unsigned int data)
{
/* PCM area (8K) mirrored into $xF0000-$xF7FFF */
if (!(address & 0x8000))
{
/* get /LDS only */
if (address & 1)
{
pcm_write((address >> 1) & 0x1fff, data, s68k.cycles);
return;
}
s68k_unused_8_w(address, data);
return;
}
#ifdef LOG_SCD
error("[%d][%d]write byte CD register %X -> 0x%02x (%X)\n", v_counter, s68k.cycles, address, data, s68k.pc);
#endif
/* Gate-Array registers */
switch (address & 0x1ff)
{
case 0x00: /* LED status */
{
/* register $00 is reserved for MAIN-CPU, use $06 instead */
scd.regs[0x06 >> 1].byte.h = data;
return;
}
case 0x01: /* RESET status */
{
/* RESET bit cleared ? */
if (!(data & 0x01))
{
/* reset CD hardware */
scd_reset(0);
}
return;
}
case 0x03: /* Memory Mode */
case 0x02: /* !LDS and !UDS are ignored (verified on real hardware, cf. Krikzz's mcd-verificator) */
{
s68k_poll_sync(1<<0x03);
/* detect MODE & RET bits modifications */
if ((data ^ scd.regs[0x03 >> 1].byte.l) & 0x05)
{
int i;
/* MODE bit */
if (data & 0x04)
{
/* 2M->1M mode switch */
if (!(scd.regs[0x03 >> 1].byte.l & 0x04))
{
/* re-arrange Word-RAM banks */
word_ram_switch(0x04);
}
/* RET bit in 1M Mode */
if (data & 0x01)
{
/* Word-RAM 1 assigned to MAIN-CPU */
for (i=scd.cartridge.boot+0x20; i<scd.cartridge.boot+0x22; i++)
{
/* Word-RAM 1 data mapped at $200000-$21FFFF */
m68k.memory_map[i].base = scd.word_ram[1] + ((i & 0x01) << 16);
}
for (i=scd.cartridge.boot+0x22; i<scd.cartridge.boot+0x24; i++)
{
/* VRAM cell image mapped at $220000-$23FFFF */
m68k.memory_map[i].read8 = cell_ram_1_read8;
m68k.memory_map[i].read16 = cell_ram_1_read16;
m68k.memory_map[i].write8 = cell_ram_1_write8;
m68k.memory_map[i].write16 = cell_ram_1_write16;
zbank_memory_map[i].read = cell_ram_1_read8;
zbank_memory_map[i].write = cell_ram_1_write8;
}
/* Word-RAM 0 assigned to SUB-CPU */
for (i=0x08; i<0x0c; i++)
{
/* DOT image mapped at $080000-$0BFFFF */
s68k.memory_map[i].read8 = dot_ram_0_read8;
s68k.memory_map[i].read16 = dot_ram_0_read16;
s68k.memory_map[i].write8 = dot_ram_0_write8;
s68k.memory_map[i].write16 = dot_ram_0_write16;
}
for (i=0x0c; i<0x0e; i++)
{
/* Word-RAM 0 data mapped at $0C0000-$0DFFFF */
s68k.memory_map[i].base = scd.word_ram[0] + ((i & 0x01) << 16);
}
/* writing 1 to RET bit in 1M mode returns Word-RAM to MAIN-CPU in 2M mode */
scd.dmna = 0;
}
else
{
/* Word-RAM 0 assigned to MAIN-CPU */
for (i=scd.cartridge.boot+0x20; i<scd.cartridge.boot+0x22; i++)
{
/* Word-RAM 0 data mapped at $200000-$21FFFF */
m68k.memory_map[i].base = scd.word_ram[0] + ((i & 0x01) << 16);
}
for (i=scd.cartridge.boot+0x22; i<scd.cartridge.boot+0x24; i++)
{
/* VRAM cell image mapped at $220000-$23FFFF */
m68k.memory_map[i].read8 = cell_ram_0_read8;
m68k.memory_map[i].read16 = cell_ram_0_read16;
m68k.memory_map[i].write8 = cell_ram_0_write8;
m68k.memory_map[i].write16 = cell_ram_0_write16;
zbank_memory_map[i].read = cell_ram_0_read8;
zbank_memory_map[i].write = cell_ram_0_write8;
}
/* Word-RAM 1 assigned to SUB-CPU */
for (i=0x08; i<0x0c; i++)
{
/* DOT image mapped at $080000-$0BFFFF */
s68k.memory_map[i].read8 = dot_ram_1_read8;
s68k.memory_map[i].read16 = dot_ram_1_read16;
s68k.memory_map[i].write8 = dot_ram_1_write8;
s68k.memory_map[i].write16 = dot_ram_1_write16;
}
for (i=0x0c; i<0x0e; i++)
{
/* Word-RAM 1 data mapped at $0C0000-$0DFFFF */
s68k.memory_map[i].base = scd.word_ram[1] + ((i & 0x01) << 16);
}
}
/* clear DMNA bit (swap completed) */
scd.regs[0x02 >> 1].byte.l = (scd.regs[0x02 >> 1].byte.l & ~0x1f) | (data & 0x1d);
return;
}
else
{
/* 1M->2M mode switch */
if (scd.regs[0x02 >> 1].byte.l & 0x04)
{
/* re-arrange Word-RAM banks */
word_ram_switch(0x00);
/* RET bit set during 1M mode ? */
data |= ~scd.dmna & 0x01;
/* check if RET bit is cleared */
if (!(data & 0x01))
{
/* MAIN-CPU: $200000-$23FFFF is unmapped */
for (i=scd.cartridge.boot+0x20; i<scd.cartridge.boot+0x24; i++)
{
m68k.memory_map[i].read8 = m68k_read_bus_8;
m68k.memory_map[i].read16 = m68k_read_bus_16;
m68k.memory_map[i].write8 = m68k_unused_8_w;
m68k.memory_map[i].write16 = m68k_unused_16_w;
zbank_memory_map[i].read = zbank_unused_r;
zbank_memory_map[i].write = zbank_unused_w;
}
/* SUB-CPU: access to Word-RAM in $08FFFF-$0BFFFF is unlocked (/DTACK asserted) */
for (i=0x08; i<0x0c; i++)
{
s68k.memory_map[i].read8 = NULL;
s68k.memory_map[i].read16 = NULL;
s68k.memory_map[i].write8 = NULL;
s68k.memory_map[i].write16 = NULL;
}
/* set DMNA bit */
data |= 0x02;
/* mask BK0-1 bits (MAIN-CPU side only) */
scd.regs[0x02 >> 1].byte.l = (scd.regs[0x02 >> 1].byte.l & ~0x1f) | (data & 0x1f);
return;
}
}
/* RET bit set in 2M mode */
if (data & 0x01)
{
/* check if graphics operation is running */
if (scd.regs[0x58>>1].byte.h & 0x80)
{
/* synchronize GFX processing with SUB-CPU */
gfx_update(s68k.cycles);
}
/* check if CDC DMA to 2M Word-RAM is running */
if (cdc.dma_w == word_ram_2M_dma_w)
{
/* synchronize CDC DMA with SUB-CPU */
cdc_dma_update(s68k.cycles);
/* halt CDC DMA to 2M Word-RAM (if still running) */
cdc.halted_dma_w = cdc.dma_w;
cdc.dma_w = 0;
}
/* Word-RAM is returned to MAIN-CPU */
scd.dmna = 0;
/* MAIN-CPU: $200000-$23FFFF is mapped to Word-RAM */
for (i=scd.cartridge.boot+0x20; i<scd.cartridge.boot+0x24; i++)
{
m68k.memory_map[i].read8 = NULL;
m68k.memory_map[i].read16 = NULL;
m68k.memory_map[i].write8 = NULL;
m68k.memory_map[i].write16 = NULL;
zbank_memory_map[i].read = NULL;
zbank_memory_map[i].write = NULL;
}
/* SUB-CPU: access to Word-RAM in $08FFFF-$0BFFFF is locked (/DTACK not asserted) */
for (i=0x08; i<0x0c; i++)
{
s68k.memory_map[i].read8 = s68k_lockup_r_8;
s68k.memory_map[i].read16 = s68k_lockup_r_16;
s68k.memory_map[i].write8 = s68k_lockup_w_8;
s68k.memory_map[i].write16 = s68k_lockup_w_16;
}
/* clear DMNA bit */
scd.regs[0x02 >> 1].byte.l = (scd.regs[0x02 >> 1].byte.l & ~0x1f) | (data & 0x1d);
return;
}
}
}
/* update PM0-1 & MODE bits */
scd.regs[0x02 >> 1].byte.l = (scd.regs[0x02 >> 1].byte.l & ~0x1c) | (data & 0x1c);
return;
}
case 0x04: /* CDC mode */
{
scd.regs[0x04 >> 1].byte.h = data & 0x07;
/* synchronize CDC DMA (if running) with SUB-CPU */
if (cdc.dma_w)
{
cdc_dma_update(s68k.cycles);
}
/* reinitialize CDC data transfer destination (verified on real hardware, cf. Krikzz's mcd-verificator) */
cdc_dma_init();
/* reset CDC DMA address (verified on real hardware, cf. Krikzz's mcd-verificator) */
scd.regs[0x0a >> 1].w = 0;
return;
}
case 0x05: /* CDC register address */
{
scd.regs[0x04 >> 1].byte.l = data & cdc.ar_mask;
return;
}
case 0x07: /* CDC register write */
{
cdc_reg_w(data);
return;
}
case 0x0f: /* SUB-CPU communication flags */
case 0x0e: /* !LDS and !UDS are ignored (verified on real hardware, cf. Krikzz's mcd-verificator, Space Ace, Dragon's Lair) */
{
s68k_poll_sync(1<<0x0f);
scd.regs[0x0f>>1].byte.l = data;
return;
}
case 0x31: /* Timer */
case 0x30: /* !LDS and !UDS are ignored (verified on real hardware, cf. Krikzz's mcd-verificator) */
{
/* reload timer (one timer clock = 384 CPU cycles) */
scd.timer = data * TIMERS_SCYCLES_RATIO;
/* only non-zero data starts timer, writing zero stops it */
if (data)
{
/* adjust regarding current CPU cycle */
scd.timer += (s68k.cycles - scd.cycles);
}
scd.regs[0x30>>1].byte.l = data;
return;
}
case 0x33: /* Interrupts */
{
/* update register value before updating interrupts */
scd.regs[0x32>>1].byte.l = data;
/* update IEN2 flag */
scd.regs[0x00].byte.h = (scd.regs[0x00].byte.h & 0x7f) | ((data & 0x04) << 5);
/* clear level 1 interrupt if disabled ("Batman Returns" option menu) */
scd.pending &= 0xfd | (data & 0x02);
/* update IRQ level */
s68k_update_irq((scd.pending & data) >> 1);
return;
}
case 0x4d: /* Font Color */
case 0x4c: /* !LDS and !UDS are ignored (verified on real hardware, cf. Krikzz's mcd-verificator) */
{
scd.regs[0x4c>>1].byte.l = data;
break;
}
default:
{
uint16 reg_16 = address & 0x1fe;
/* SUB-CPU communication words */
if ((reg_16 >= 0x20) && (reg_16 <= 0x2f))
{
s68k_poll_sync(1 << ((address - 0x10) & 0x1f));
}
/* MAIN-CPU communication words */
else if ((reg_16 >= 0x10) && (reg_16 <= 0x1f))
{
/* read-only (Sega Classic Arcade Collection) */
return;
}
/* word-only registers */
else if (((reg_16 >= 0x08) && (reg_16 <= 0x0d)) ||
((reg_16 >= 0x34) && (reg_16 <= 0x35)) ||
((reg_16 >= 0x5a) && (reg_16 <= 0x67)))
{
scd_write_word(address, (data << 8) | (data & 0xff));
return;
}
/* default registers */
if (address & 1)
{
/* register LSB */
scd.regs[reg_16 >> 1].byte.l = data;
return;
}
/* register MSB */
scd.regs[reg_16 >> 1].byte.h = data;
return;
}
}
}
static void scd_write_word(unsigned int address, unsigned int data)
{
/* PCM area (8K) mirrored into $xF0000-$xF7FFF */
if (!(address & 0x8000))
{
/* get /LDS only */
pcm_write((address >> 1) & 0x1fff, data & 0xff, s68k.cycles);
return;
}
#ifdef LOG_SCD
error("[%d][%d]write word CD register %X -> 0x%04x (%X)\n", v_counter, s68k.cycles, address, data, s68k.pc);
#endif
/* Gate-Array registers */
switch (address & 0x1fe)
{
case 0x00: /* LED status & RESET */
{
/* only update LED status (register $00 is reserved for MAIN-CPU, use $06 instead) */
scd.regs[0x06>>1].byte.h = data >> 8;
/* RESET bit cleared ? */
if (!(data & 0x01))
{
/* reset CD hardware */
scd_reset(0);
}
return;
}
case 0x02: /* Memory Mode */
{
s68k_poll_sync(1<<0x03);
/* detect MODE & RET bits modifications */
if ((data ^ scd.regs[0x03>>1].byte.l) & 0x05)
{
int i;
/* MODE bit */
if (data & 0x04)
{
/* 2M->1M mode switch */
if (!(scd.regs[0x03 >> 1].byte.l & 0x04))
{
/* re-arrange Word-RAM banks */
word_ram_switch(0x04);
}
/* RET bit in 1M Mode */
if (data & 0x01)
{
/* Word-RAM 1 assigned to MAIN-CPU */
for (i=scd.cartridge.boot+0x20; i<scd.cartridge.boot+0x22; i++)
{
/* Word-RAM 1 data mapped at $200000-$21FFFF */
m68k.memory_map[i].base = scd.word_ram[1] + ((i & 0x01) << 16);
}
for (i=scd.cartridge.boot+0x22; i<scd.cartridge.boot+0x24; i++)
{
/* VRAM cell image mapped at $220000-$23FFFF */
m68k.memory_map[i].read8 = cell_ram_1_read8;
m68k.memory_map[i].read16 = cell_ram_1_read16;
m68k.memory_map[i].write8 = cell_ram_1_write8;
m68k.memory_map[i].write16 = cell_ram_1_write16;
zbank_memory_map[i].read = cell_ram_1_read8;
zbank_memory_map[i].write = cell_ram_1_write8;
}
/* Word-RAM 0 assigned to SUB-CPU */
for (i=0x08; i<0x0c; i++)
{
/* DOT image mapped at $080000-$0BFFFF */
s68k.memory_map[i].read8 = dot_ram_0_read8;
s68k.memory_map[i].read16 = dot_ram_0_read16;
s68k.memory_map[i].write8 = dot_ram_0_write8;
s68k.memory_map[i].write16 = dot_ram_0_write16;
}
for (i=0x0c; i<0x0e; i++)
{
/* Word-RAM 0 data mapped at $0C0000-$0DFFFF */
s68k.memory_map[i].base = scd.word_ram[0] + ((i & 0x01) << 16);
}
/* writing 1 to RET bit in 1M mode returns Word-RAM to MAIN-CPU in 2M mode */
scd.dmna = 0;
}
else
{
/* Word-RAM 0 assigned to MAIN-CPU */
for (i=scd.cartridge.boot+0x20; i<scd.cartridge.boot+0x22; i++)
{
/* Word-RAM 0 data mapped at $200000-$21FFFF */
m68k.memory_map[i].base = scd.word_ram[0] + ((i & 0x01) << 16);
}
for (i=scd.cartridge.boot+0x22; i<scd.cartridge.boot+0x24; i++)
{
/* VRAM cell image mapped at $220000-$23FFFF */
m68k.memory_map[i].read8 = cell_ram_0_read8;
m68k.memory_map[i].read16 = cell_ram_0_read16;
m68k.memory_map[i].write8 = cell_ram_0_write8;
m68k.memory_map[i].write16 = cell_ram_0_write16;
zbank_memory_map[i].read = cell_ram_0_read8;
zbank_memory_map[i].write = cell_ram_0_write8;
}
/* Word-RAM 1 assigned to SUB-CPU */
for (i=0x08; i<0x0c; i++)
{
/* DOT image mapped at $080000-$0BFFFF */
s68k.memory_map[i].read8 = dot_ram_1_read8;
s68k.memory_map[i].read16 = dot_ram_1_read16;
s68k.memory_map[i].write8 = dot_ram_1_write8;
s68k.memory_map[i].write16 = dot_ram_1_write16;
}
for (i=0x0c; i<0x0e; i++)
{
/* Word-RAM 1 data mapped at $0C0000-$0DFFFF */
s68k.memory_map[i].base = scd.word_ram[1] + ((i & 0x01) << 16);
}
}
/* clear DMNA bit (swap completed) */
scd.regs[0x03>>1].byte.l = (scd.regs[0x03>>1].byte.l & ~0x1f) | (data & 0x1d);
return;
}
else
{
/* 1M->2M mode switch */
if (scd.regs[0x03>>1].byte.l & 0x04)
{
/* re-arrange Word-RAM banks */
word_ram_switch(0x00);
/* RET bit set during 1M mode ? */
data |= ~scd.dmna & 0x01;
/* check if RET bit is cleared */
if (!(data & 0x01))
{
/* MAIN-CPU: $200000-$23FFFF is unmapped */
for (i=scd.cartridge.boot+0x20; i<scd.cartridge.boot+0x24; i++)
{
m68k.memory_map[i].read8 = m68k_read_bus_8;
m68k.memory_map[i].read16 = m68k_read_bus_16;
m68k.memory_map[i].write8 = m68k_unused_8_w;
m68k.memory_map[i].write16 = m68k_unused_16_w;
zbank_memory_map[i].read = zbank_unused_r;
zbank_memory_map[i].write = zbank_unused_w;
}
/* SUB-CPU: access to Word-RAM in $08FFFF-$0BFFFF is unlocked (/DTACK asserted) */
for (i=0x08; i<0x0c; i++)
{
s68k.memory_map[i].read8 = NULL;
s68k.memory_map[i].read16 = NULL;
s68k.memory_map[i].write8 = NULL;
s68k.memory_map[i].write16 = NULL;
}
/* set DMNA bit */
data |= 0x02;
/* mask BK0-1 bits (MAIN-CPU side only) */
scd.regs[0x03>>1].byte.l = (scd.regs[0x03>>1].byte.l & ~0x1f) | (data & 0x1f);
return;
}
}
/* RET bit set in 2M mode */
if (data & 0x01)
{
/* check if graphics operation is running */
if (scd.regs[0x58>>1].byte.h & 0x80)
{
/* synchronize GFX processing with SUB-CPU */
gfx_update(s68k.cycles);
}
/* check if CDC DMA to 2M Word-RAM is running */
if (cdc.dma_w == word_ram_2M_dma_w)
{
/* synchronize CDC DMA with SUB-CPU */
cdc_dma_update(s68k.cycles);
/* halt CDC DMA to 2M Word-RAM (if still running) */
cdc.halted_dma_w = cdc.dma_w;
cdc.dma_w = 0;
}
/* Word-RAM is returned to MAIN-CPU */
scd.dmna = 0;
/* MAIN-CPU: $200000-$23FFFF is mapped to Word-RAM */
for (i=scd.cartridge.boot+0x20; i<scd.cartridge.boot+0x24; i++)
{
m68k.memory_map[i].read8 = NULL;
m68k.memory_map[i].read16 = NULL;
m68k.memory_map[i].write8 = NULL;
m68k.memory_map[i].write16 = NULL;
zbank_memory_map[i].read = NULL;
zbank_memory_map[i].write = NULL;
}
/* SUB-CPU: access to Word-RAM in $08FFFF-$0BFFFF is locked (/DTACK not asserted) */
for (i=0x08; i<0x0c; i++)
{
s68k.memory_map[i].read8 = s68k_lockup_r_8;
s68k.memory_map[i].read16 = s68k_lockup_r_16;
s68k.memory_map[i].write8 = s68k_lockup_w_8;
s68k.memory_map[i].write16 = s68k_lockup_w_16;
}
/* clear DMNA bit */
scd.regs[0x03>>1].byte.l = (scd.regs[0x03>>1].byte.l & ~0x1f) | (data & 0x1d);
return;
}
}
}
/* update PM0-1 & MODE bits */
scd.regs[0x03>>1].byte.l = (scd.regs[0x03>>1].byte.l & ~0x1c) | (data & 0x1c);
return;
}
case 0x04: /* CDC mode & register address */
{
scd.regs[0x04 >> 1].w = data & (0x0700 | cdc.ar_mask);
/* synchronize CDC DMA (if running) with SUB-CPU */
if (cdc.dma_w)
{
cdc_dma_update(s68k.cycles);
}
/* reinitialize CDC data transfer destination (verified on real hardware, cf. Krikzz's mcd-verificator) */
cdc_dma_init();
/* reset CDC DMA address (verified on real hardware, cf. Krikzz's mcd-verificator) */
scd.regs[0x0a >> 1].w = 0;
return;
}
case 0x06: /* CDC register write */
{
cdc_reg_w(data);
return;
}
case 0x08: /* CDC host data */
{
/* CDC data is also read (although unused) on write access (verified on real hardware, cf. Krikzz's mcd-verificator) */
cdc_host_r(CDC_SUB_CPU_ACCESS);
return;
}
case 0x0c: /* Stopwatch */
{
/* synchronize the counter with SUB-CPU */
int ticks = (s68k.cycles - scd.stopwatch) / TIMERS_SCYCLES_RATIO;
scd.stopwatch += (ticks * TIMERS_SCYCLES_RATIO);
/* any writes clear the counter */
scd.regs[0x0c>>1].w = 0;
return;
}
case 0x0e: /* CPU Communication flags */
{
s68k_poll_sync(1<<0x0f);
/* D8-D15 ignored -> only SUB-CPU flags are updated */
scd.regs[0x0f>>1].byte.l = data & 0xff;
return;
}
case 0x30: /* Timer */
{
/* LSB only */
data &= 0xff;
/* reload timer (one timer clock = 384 CPU cycles) */
scd.timer = data * TIMERS_SCYCLES_RATIO;
/* only non-zero data starts timer, writing zero stops it */
if (data)
{
/* adjust regarding current CPU cycle */
scd.timer += (s68k.cycles - scd.cycles);
}
scd.regs[0x30>>1].byte.l = data;
return;
}
case 0x32: /* Interrupts */
{
/* LSB only */
data &= 0xff;
/* update register value before updating interrupts */
scd.regs[0x32>>1].byte.l = data;
/* update IEN2 flag */
scd.regs[0x00].byte.h = (scd.regs[0x00].byte.h & 0x7f) | ((data & 0x04) << 5);
/* clear pending level 1 interrupt if disabled ("Batman Returns" option menu) */
scd.pending &= 0xfd | (data & 0x02);
/* update IRQ level */
s68k_update_irq((scd.pending & data) >> 1);
return;
}
case 0x34: /* CD Fader */
{
/* Wondermega hardware (CXD2554M digital filter) */
if (scd.type == CD_TYPE_WONDERMEGA)
{
/* only MSB is latched by CXD2554M chip, LSB is ignored (8-bit digital filter) */
/* attenuator data is 7-bit only (bits 0-7) */
data = (data >> 8) & 0x7f;
/* scale CXD2554M volume (0-127) to full (LC7883KM compatible) volume range (0-1024) */
cdd.fader[1] = (1024 * data) / 127 ;
}
/* Wondermega M2 / X'Eye hardware (SM5841A digital filter) */
else if (scd.type == CD_TYPE_WONDERMEGA_M2)
{
/* only MSB is latched by SM5841A chip, LSB is ignored (8-bit digital filter) */
data = data >> 8;
/* attenuator data is set only when command bit (bit 0) is cleared (other commands are ignored) */
if (data & 0x01) return;
/* attenuator data is 7-bit only (bits 8-1) and reverted (bit 1 = msb) */
/* bit reversing formula taken from http://graphics.stanford.edu/~seander/bithacks.html#ReverseByteWith32Bits */
data = (((((data * 0x0802) & 0x22110) | ((data * 0x8020) & 0x88440)) * 0x10101) >> 16) & 0x7f;
/* convert & scale SM5841A attenuation (127-0) to full (LC7883KM compatible) volume range (0-1024) */
cdd.fader[1] = (1024 * (127 - data)) / 127 ;
}
/* default CD hardware (LC7883KM digital filter) */
else
{
/* get LC7883KM volume data (12-bit) */
cdd.fader[1] = data >> 4 ;
}
return;
}
case 0x36: /* CDD control */
{
/* only bit 2 is writable (bits [1:0] forced to 0 by default) */
scd.regs[0x37>>1].byte.l = data & 0x04;
return;
}
case 0x4a: /* CDD command 9 (controlled by BIOS, word access only ?) */
{
scd.regs[0x4a>>1].w = 0;
cdd_process();
#ifdef LOG_CDD
error("CDD command: %02x %02x %02x %02x %02x %02x %02x %02x\n",scd.regs[0x42>>1].byte.h, scd.regs[0x42>>1].byte.l, scd.regs[0x44>>1].byte.h, scd.regs[0x44>>1].byte.l, scd.regs[0x46>>1].byte.h, scd.regs[0x46>>1].byte.l, scd.regs[0x48>>1].byte.h, scd.regs[0x48>>1].byte.l);
error("CDD status: %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",scd.regs[0x38>>1].byte.h, scd.regs[0x38>>1].byte.l, scd.regs[0x3a>>1].byte.h, scd.regs[0x3a>>1].byte.l, scd.regs[0x3c>>1].byte.h, scd.regs[0x3c>>1].byte.l, scd.regs[0x3e>>1].byte.h, scd.regs[0x3e>>1].byte.l, scd.regs[0x40>>1].byte.h, scd.regs[0x40>>1].byte.l);
#endif
break;
}
case 0x66: /* Trace vector base address */
{
scd.regs[0x66>>1].w = data;
/* start GFX operation */
gfx_start(data, s68k.cycles);
return;
}
default:
{
/* SUB-CPU communication words */
if ((address & 0x1f0) == 0x20)
{
s68k_poll_sync(3 << ((address - 0x10) & 0x1e));
}
/* MAIN-CPU communication words */
else if ((address & 0x1f0) == 0x10)
{
/* read-only (Sega Classic Arcade Collection) */
return;
}
/* default registers */
scd.regs[(address >> 1) & 0xff].w = data;
return;
}
}
}
void scd_init(void)
{
int i;
/****************************************************************/
/* MAIN-CPU low memory map ($000000-$7FFFFF) */
/****************************************************************/
/* 0x00: boot from CD (default) */
/* 0x40: boot from cartridge (mode 1) when /CART is asserted */
int base = scd.cartridge.boot;
/* $400000-$7FFFFF (resp. $000000-$3FFFFF): cartridge port (/CE0 asserted) */
cd_cart_init();
/* $000000-$1FFFFF (resp. $400000-$5FFFFF): expansion port (/ROM asserted) */
for (i=base+0x00; i<base+0x20; i++)
{
/* only VA1-VA17 are connected to expansion port */
switch (i & 0x02)
{
case 0x00:
{
/* $000000-$01FFFF (resp. $400000-$41FFFF): internal ROM (128KB), mirrored every 256KB up to $1FFFFF (resp. $5FFFFF) */
m68k.memory_map[i].base = scd.bootrom + ((i & 0x01) << 16);
m68k.memory_map[i].read8 = NULL;
m68k.memory_map[i].read16 = NULL;
m68k.memory_map[i].write8 = m68k_unused_8_w;
m68k.memory_map[i].write16 = m68k_unused_16_w;
zbank_memory_map[i].read = NULL;
zbank_memory_map[i].write = zbank_unused_w;
break;
}
case 0x02:
{
/* $020000-$03FFFF (resp. $420000-$43FFFF): PRG-RAM (first 128KB bank), mirrored every 256KB up to $1FFFFF (resp. $5FFFFF) */
m68k.memory_map[i].base = scd.prg_ram + ((i & 0x01) << 16);
/* automatic mirrored range remapping when switching PRG-RAM banks */
if (i > (base + 0x03))
{
m68k.memory_map[i].read8 = prg_ram_m68k_read_byte;
m68k.memory_map[i].read16 = prg_ram_m68k_read_word;
m68k.memory_map[i].write8 = prg_ram_m68k_write_byte;
m68k.memory_map[i].write16 = prg_ram_m68k_write_word;
zbank_memory_map[i].read = prg_ram_z80_read_byte;
zbank_memory_map[i].write = prg_ram_z80_write_byte;
}
else
{
m68k.memory_map[i].read8 = NULL;
m68k.memory_map[i].read16 = NULL;
m68k.memory_map[i].write8 = NULL;
m68k.memory_map[i].write16 = NULL;
zbank_memory_map[i].read = NULL;
zbank_memory_map[i].write = NULL;
}
break;
}
}
}
/* $200000-$3FFFFF (resp. $600000-$7FFFFF): expansion port (/RAS2 asserted) */
for (i=base+0x20; i<base+0x40; i++)
{
/* $200000-$23FFFF (resp. $600000-$63FFFF): Word-RAM in 2M mode (256KB), mirrored up to $3FFFFF (resp. $7FFFFF) */
m68k.memory_map[i].base = scd.word_ram_2M + ((i & 0x03) << 16);
/* automatic mirrored range remapping when switching Word-RAM */
if (i > (base + 0x23))
{
m68k.memory_map[i].read8 = word_ram_m68k_read_byte;
m68k.memory_map[i].read16 = word_ram_m68k_read_word;
m68k.memory_map[i].write8 = word_ram_m68k_write_byte;
m68k.memory_map[i].write16 = word_ram_m68k_write_word;
zbank_memory_map[i].read = word_ram_z80_read_byte;
zbank_memory_map[i].write = word_ram_z80_write_byte;
}
else
{
m68k.memory_map[i].read8 = NULL;
m68k.memory_map[i].read16 = NULL;
m68k.memory_map[i].write8 = NULL;
m68k.memory_map[i].write16 = NULL;
zbank_memory_map[i].read = NULL;
zbank_memory_map[i].write = NULL;
}
}
/****************************************************************/
/* SUB-CPU memory map ($000000-$FFFFFF) */
/****************************************************************/
for (i=0x00; i<0x100; i++)
{
/* only A1-A19 are connected to SUB-CPU */
switch (i & 0x0f)
{
case 0x00:
case 0x01:
case 0x02:
case 0x03:
case 0x04:
case 0x05:
case 0x06:
case 0x07:
{
/* $000000-$07FFFF (mirrored every 1MB): PRG-RAM (512KB) */
s68k.memory_map[i].base = scd.prg_ram + ((i & 0x07) << 16);
s68k.memory_map[i].read8 = NULL;
s68k.memory_map[i].read16 = NULL;
/* first 128KB can be write-protected */
s68k.memory_map[i].write8 = (i & 0x0e) ? NULL : prg_ram_write_byte;
s68k.memory_map[i].write16 = (i & 0x0e) ? NULL : prg_ram_write_word;
break;
}
case 0x08:
case 0x09:
case 0x0a:
case 0x0b:
{
/* $080000-$0BFFFF (mirrored every 1MB): Word-RAM in 2M mode (256KB)*/
s68k.memory_map[i].base = scd.word_ram_2M + ((i & 0x03) << 16);
/* automatic mirrored range remapping when switching Word-RAM */
if (i > 0x0f)
{
s68k.memory_map[i].read8 = word_ram_s68k_read_byte;
s68k.memory_map[i].read16 = word_ram_s68k_read_word;
s68k.memory_map[i].write8 = word_ram_s68k_write_byte;
s68k.memory_map[i].write16 = word_ram_s68k_write_word;
}
else
{
/* access to Word-RAM in $08FFFF-$0BFFFF is locked by default (/DTACK not asserted) */
s68k.memory_map[i].read8 = s68k_lockup_r_8;
s68k.memory_map[i].read16 = s68k_lockup_r_16;
s68k.memory_map[i].write8 = s68k_lockup_w_8;
s68k.memory_map[i].write16 = s68k_lockup_w_16;
}
break;
}
case 0x0c:
case 0x0d:
{
/* $0C0000-$0DFFFF (mirrored every 1MB): unused in 2M mode (?) */
s68k.memory_map[i].base = scd.word_ram_2M + ((i & 0x03) << 16);
/* automatic mirrored range remapping when switching Word-RAM */
if (i > 0x0f)
{
s68k.memory_map[i].read8 = word_ram_s68k_read_byte;
s68k.memory_map[i].read16 = word_ram_s68k_read_word;
s68k.memory_map[i].write8 = word_ram_s68k_write_byte;
s68k.memory_map[i].write16 = word_ram_s68k_write_word;
}
else
{
s68k.memory_map[i].read8 = s68k_read_bus_8;
s68k.memory_map[i].read16 = s68k_read_bus_16;
s68k.memory_map[i].write8 = s68k_unused_8_w;
s68k.memory_map[i].write16 = s68k_unused_16_w;
}
break;
}
case 0x0e:
{
/* $FE0000-$FEFFFF (mirrored every 1MB): 8KB backup RAM */
s68k.memory_map[i].base = NULL;
s68k.memory_map[i].read8 = bram_read_byte;
s68k.memory_map[i].read16 = bram_read_word;
s68k.memory_map[i].write8 = bram_write_byte;
s68k.memory_map[i].write16 = bram_write_word;
break;
}
case 0x0f:
{
/* $FF0000-$FFFFFF (mirrored every 1MB): PCM hardware & SUB-CPU registers */
s68k.memory_map[i].base = NULL;
s68k.memory_map[i].read8 = scd_read_byte;
s68k.memory_map[i].read16 = scd_read_word;
s68k.memory_map[i].write8 = scd_write_byte;
s68k.memory_map[i].write16 = scd_write_word;
break;
}
}
}
/* Initialize CD hardware */
cdc_init();
gfx_init();
/* Initialize CD hardware master clock count per scanline */
scd.cycles_per_line = (uint32) (MCYCLES_PER_LINE * ((float)SCD_CLOCK / (float)system_clock));
/* Clear RAM */
memset(scd.prg_ram, 0x00, sizeof(scd.prg_ram));
memset(scd.word_ram, 0x00, sizeof(scd.word_ram));
memset(scd.word_ram_2M, 0x00, sizeof(scd.word_ram_2M));
memset(scd.bram, 0x00, sizeof(scd.bram));
}
void scd_reset(int hard)
{
if (hard)
{
int i;
/* Clear all ASIC registers by default */
memset(scd.regs, 0, sizeof(scd.regs));
/* Clear pending DMNA write status */
scd.dmna = 0;
/* H-INT default vector */
*(uint16 *)(m68k.memory_map[scd.cartridge.boot].base + 0x70) = 0xFFFF;
*(uint16 *)(m68k.memory_map[scd.cartridge.boot].base + 0x72) = 0xFFFF;
/* Power ON initial values (MAIN-CPU side) */
scd.regs[0x00>>1].w = 0x0002;
scd.regs[0x02>>1].w = 0x0001;
/* 2M mode */
word_ram_switch(0);
/* MAIN-CPU access to Word-RAM at $200000-$23FFFF is enabled on reset */
for (i=scd.cartridge.boot+0x20; i<scd.cartridge.boot+0x24; i++)
{
m68k.memory_map[i].read8 = NULL;
m68k.memory_map[i].read16 = NULL;
m68k.memory_map[i].write8 = NULL;
m68k.memory_map[i].write16 = NULL;
zbank_memory_map[i].read = NULL;
zbank_memory_map[i].write = NULL;
}
/* SUB-CPU access to Word-RAM at $08FFFF-$0BFFFF is locked on reset (/DTACK not asserted) */
for (i=0x08; i<0x0c; i++)
{
s68k.memory_map[i].read8 = s68k_lockup_r_8;
s68k.memory_map[i].read16 = s68k_lockup_r_16;
s68k.memory_map[i].write8 = s68k_lockup_w_8;
s68k.memory_map[i].write16 = s68k_lockup_w_16;
}
/* reset PRG-RAM bank on MAIN-CPU side */
m68k.memory_map[scd.cartridge.boot + 0x02].base = scd.prg_ram;
m68k.memory_map[scd.cartridge.boot + 0x03].base = scd.prg_ram + 0x10000;
/* allow access to PRG-RAM from MAIN-CPU */
m68k.memory_map[scd.cartridge.boot + 0x02].read8 = NULL;
m68k.memory_map[scd.cartridge.boot + 0x03].read8 = NULL;
m68k.memory_map[scd.cartridge.boot + 0x02].read16 = NULL;
m68k.memory_map[scd.cartridge.boot + 0x03].read16 = NULL;
m68k.memory_map[scd.cartridge.boot + 0x02].write8 = NULL;
m68k.memory_map[scd.cartridge.boot + 0x03].write8 = NULL;
m68k.memory_map[scd.cartridge.boot + 0x02].write16 = NULL;
m68k.memory_map[scd.cartridge.boot + 0x03].write16 = NULL;
zbank_memory_map[scd.cartridge.boot + 0x02].read = NULL;
zbank_memory_map[scd.cartridge.boot + 0x03].read = NULL;
zbank_memory_map[scd.cartridge.boot + 0x02].write = NULL;
zbank_memory_map[scd.cartridge.boot + 0x03].write = NULL;
/* reset & halt SUB-CPU */
s68k.cycles = 0;
s68k_pulse_reset();
s68k_pulse_halt();
/* Reset frame cycle counter */
scd.cycles = 0;
}
else
{
/* TODO: figure what exactly is reset when RESET bit is cleared by SUB-CPU */
/* Clear only SUB-CPU side registers (communication registers are not cleared, see msu-md-sample.bin) */
scd.regs[0x04>>1].w = 0x0000;
scd.regs[0x0c>>1].w = 0x0000;
memset(&scd.regs[0x30>>1], 0, sizeof(scd.regs) - 0x30);
}
/* SUB-CPU side default values */
scd.regs[0x08>>1].w = 0xffff;
scd.regs[0x0a>>1].w = 0xffff;
scd.regs[0x36>>1].w = 0x0100;
scd.regs[0x40>>1].w = 0x000f;
scd.regs[0x42>>1].w = 0xffff;
scd.regs[0x44>>1].w = 0xffff;
scd.regs[0x46>>1].w = 0xffff;
scd.regs[0x48>>1].w = 0xffff;
scd.regs[0x4a>>1].w = 0xffff;
/* RESET register always return 1 (register $06 is unused by both sides, it is used for SUB-CPU first register) */
scd.regs[0x06>>1].byte.l = 0x01;
/* Reset Timer & Stopwatch counters */
scd.timer = 0;
scd.stopwatch = s68k.cycles;
/* Clear pending interrupts */
scd.pending = 0;
/* Clear CPU polling detection */
memset(&m68k.poll, 0, sizeof(m68k.poll));
memset(&s68k.poll, 0, sizeof(s68k.poll));
/* reset CDD cycle counter */
cdd.cycles = (scd.cycles - s68k.cycles) * 3;
/* Reset CD hardware */
cdd_reset();
cdc_reset();
gfx_reset();
pcm_reset();
}
void scd_update(unsigned int cycles)
{
int m68k_end_cycles;
int s68k_run_cycles;
int s68k_end_cycles = scd.cycles + SCYCLES_PER_LINE;
/* run both CPU in sync until end of line */
do
{
/* CD hardware remaining cycles until end of line */
s68k_run_cycles = s68k_end_cycles - scd.cycles;
/* check Timer interrupt occurence */
if ((scd.timer > 0) && (scd.timer < s68k_run_cycles))
{
/* adjust Sub-CPU and Main-CPU end cycle counters up to Timer interrupt occurence */
s68k_run_cycles = scd.timer;
m68k_end_cycles = mcycles_vdp + ((s68k_run_cycles * MCYCLES_PER_LINE) / SCYCLES_PER_LINE);
}
else
{
/* default Main-CPU end cycle counter (end of line) */
m68k_end_cycles = cycles;
}
/* run both CPU in sync until required cycle counters */
m68k_run(m68k_end_cycles);
s68k_run(scd.cycles + s68k_run_cycles);
/* increment CD hardware cycle counter */
scd.cycles += s68k_run_cycles;
/* CDD processing at 75Hz (one clock = 12500000/75 = 500000/3 CPU clocks) */
cdd.cycles += (s68k_run_cycles * 3);
if (cdd.cycles >= (500000 * 4))
{
/* reload CDD cycle counter */
cdd.cycles -= (500000 * 4);
/* update CDD sector */
cdd_update();
/* check if CDD communication is enabled */
if (scd.regs[0x37>>1].byte.l & 0x04)
{
/* pending level 4 interrupt */
scd.pending |= (1 << 4);
/* level 4 interrupt enabled */
if (scd.regs[0x32>>1].byte.l & 0x10)
{
/* update IRQ level */
s68k_update_irq((scd.pending & scd.regs[0x32>>1].byte.l) >> 1);
}
}
}
/* Timer */
if (scd.timer)
{
/* decrement timer */
scd.timer -= s68k_run_cycles;
if (scd.timer <= 0)
{
/* reload timer (one timer clock = 384 CPU cycles) */
scd.timer += (scd.regs[0x30>>1].byte.l * TIMERS_SCYCLES_RATIO);
/* level 3 interrupt enabled ? */
if (scd.regs[0x32>>1].byte.l & 0x08)
{
/* trigger level 3 interrupt */
scd.pending |= (1 << 3);
/* update IRQ level */
s68k_update_irq((scd.pending & scd.regs[0x32>>1].byte.l) >> 1);
}
}
}
}
while ((m68k.cycles < cycles) || (s68k.cycles < s68k_end_cycles));
/* update CDC DMA processing (if running) */
if (cdc.dma_w)
{
cdc_dma_update(scd.cycles);
}
/* update GFX processing (if started) */
if (scd.regs[0x58>>1].byte.h & 0x80)
{
gfx_update(scd.cycles);
}
}
void scd_end_frame(unsigned int cycles)
{
/* run Stopwatch until end of frame */
int ticks = (cycles - scd.stopwatch) / TIMERS_SCYCLES_RATIO;
scd.regs[0x0c>>1].w = (scd.regs[0x0c>>1].w + ticks) & 0xfff;
/* adjust Stopwatch counter for next frame (can be negative) */
scd.stopwatch += (ticks * TIMERS_SCYCLES_RATIO) - cycles;
/* adjust SUB-CPU, GPU and CDC cycle counters for next frame */
s68k.cycles -= cycles;
gfx.cycles -= cycles;
cdc.cycles[0] -= cycles;
cdc.cycles[1] -= cycles;
/* reset CPU registers polling */
m68k.poll.cycle = 0;
s68k.poll.cycle = 0;
}
int scd_context_save(uint8 *state)
{
uint16 tmp16;
uint32 tmp32;
int bufferptr = 0;
/* internal harware */
save_param(scd.regs, sizeof(scd.regs));
save_param(&scd.cycles, sizeof(scd.cycles));
save_param(&scd.stopwatch, sizeof(scd.stopwatch));
save_param(&scd.timer, sizeof(scd.timer));
save_param(&scd.pending, sizeof(scd.pending));
save_param(&scd.dmna, sizeof(scd.dmna));
/* GFX processor */
bufferptr += gfx_context_save(&state[bufferptr]);
/* CD Data controller */
bufferptr += cdc_context_save(&state[bufferptr]);
/* CD Drive processor */
bufferptr += cdd_context_save(&state[bufferptr]);
/* PCM chip */
bufferptr += pcm_context_save(&state[bufferptr]);
/* PRG-RAM */
save_param(scd.prg_ram, sizeof(scd.prg_ram));
/* Word-RAM */
if (scd.regs[0x03>>1].byte.l & 0x04)
{
/* 1M mode */
save_param(scd.word_ram, sizeof(scd.word_ram));
}
else
{
/* 2M mode */
save_param(scd.word_ram_2M, sizeof(scd.word_ram_2M));
}
/* MAIN-CPU & SUB-CPU polling */
save_param(&m68k.poll, sizeof(m68k.poll));
save_param(&s68k.poll, sizeof(s68k.poll));
/* H-INT default vector */
tmp16 = *(uint16 *)(m68k.memory_map[scd.cartridge.boot].base + 0x72);
save_param(&tmp16, 2);
/* SUB-CPU registers */
tmp32 = s68k_get_reg(M68K_REG_D0); save_param(&tmp32, 4);
tmp32 = s68k_get_reg(M68K_REG_D1); save_param(&tmp32, 4);
tmp32 = s68k_get_reg(M68K_REG_D2); save_param(&tmp32, 4);
tmp32 = s68k_get_reg(M68K_REG_D3); save_param(&tmp32, 4);
tmp32 = s68k_get_reg(M68K_REG_D4); save_param(&tmp32, 4);
tmp32 = s68k_get_reg(M68K_REG_D5); save_param(&tmp32, 4);
tmp32 = s68k_get_reg(M68K_REG_D6); save_param(&tmp32, 4);
tmp32 = s68k_get_reg(M68K_REG_D7); save_param(&tmp32, 4);
tmp32 = s68k_get_reg(M68K_REG_A0); save_param(&tmp32, 4);
tmp32 = s68k_get_reg(M68K_REG_A1); save_param(&tmp32, 4);
tmp32 = s68k_get_reg(M68K_REG_A2); save_param(&tmp32, 4);
tmp32 = s68k_get_reg(M68K_REG_A3); save_param(&tmp32, 4);
tmp32 = s68k_get_reg(M68K_REG_A4); save_param(&tmp32, 4);
tmp32 = s68k_get_reg(M68K_REG_A5); save_param(&tmp32, 4);
tmp32 = s68k_get_reg(M68K_REG_A6); save_param(&tmp32, 4);
tmp32 = s68k_get_reg(M68K_REG_A7); save_param(&tmp32, 4);
tmp32 = s68k_get_reg(M68K_REG_PC); save_param(&tmp32, 4);
tmp16 = s68k_get_reg(M68K_REG_SR); save_param(&tmp16, 2);
tmp32 = s68k_get_reg(M68K_REG_USP); save_param(&tmp32, 4);
tmp32 = s68k_get_reg(M68K_REG_ISP); save_param(&tmp32, 4);
/* SUB-CPU internal state */
save_param(&s68k.cycles, sizeof(s68k.cycles));
save_param(&s68k.int_level, sizeof(s68k.int_level));
save_param(&s68k.stopped, sizeof(s68k.stopped));
/* bootable MD cartridge */
if (scd.cartridge.boot)
{
bufferptr += md_cart_context_save(&state[bufferptr]);
}
return bufferptr;
}
int scd_context_load(uint8 *state, char *version)
{
int i;
uint16 tmp16;
uint32 tmp32;
int bufferptr = 0;
/* internal harware */
load_param(scd.regs, sizeof(scd.regs));
load_param(&scd.cycles, sizeof(scd.cycles));
load_param(&scd.stopwatch, sizeof(scd.stopwatch));
load_param(&scd.timer, sizeof(scd.timer));
load_param(&scd.pending, sizeof(scd.pending));
load_param(&scd.dmna, sizeof(scd.dmna));
/* GFX processor */
bufferptr += gfx_context_load(&state[bufferptr]);
/* CD Data controller */
bufferptr += cdc_context_load(&state[bufferptr]);
/* CD Drive processor */
bufferptr += cdd_context_load(&state[bufferptr], version);
/* PCM chip */
bufferptr += pcm_context_load(&state[bufferptr]);
/* PRG-RAM */
load_param(scd.prg_ram, sizeof(scd.prg_ram));
/* PRG-RAM 128K bank mapped on MAIN-CPU side */
m68k.memory_map[scd.cartridge.boot + 0x02].base = scd.prg_ram + ((scd.regs[0x03>>1].byte.l & 0xc0) << 11);
m68k.memory_map[scd.cartridge.boot + 0x03].base = m68k.memory_map[scd.cartridge.boot + 0x02].base + 0x10000;
/* PRG-RAM can only be accessed from MAIN 68K & Z80 if SUB-CPU is halted (Dungeon Explorer USA version) */
if ((scd.regs[0x00].byte.l & 0x03) != 0x01)
{
m68k.memory_map[scd.cartridge.boot + 0x02].read8 = m68k.memory_map[scd.cartridge.boot + 0x03].read8 = NULL;
m68k.memory_map[scd.cartridge.boot + 0x02].read16 = m68k.memory_map[scd.cartridge.boot + 0x03].read16 = NULL;
m68k.memory_map[scd.cartridge.boot + 0x02].write8 = m68k.memory_map[scd.cartridge.boot + 0x03].write8 = NULL;
m68k.memory_map[scd.cartridge.boot + 0x02].write16 = m68k.memory_map[scd.cartridge.boot + 0x03].write16 = NULL;
zbank_memory_map[scd.cartridge.boot + 0x02].read = zbank_memory_map[scd.cartridge.boot + 0x03].read = NULL;
zbank_memory_map[scd.cartridge.boot + 0x02].write = zbank_memory_map[scd.cartridge.boot + 0x03].write = NULL;
}
else
{
m68k.memory_map[scd.cartridge.boot + 0x02].read8 = m68k.memory_map[scd.cartridge.boot + 0x03].read8 = m68k_read_bus_8;
m68k.memory_map[scd.cartridge.boot + 0x02].read16 = m68k.memory_map[scd.cartridge.boot + 0x03].read16 = m68k_read_bus_16;
m68k.memory_map[scd.cartridge.boot + 0x02].write8 = m68k.memory_map[scd.cartridge.boot + 0x03].write8 = m68k_unused_8_w;
m68k.memory_map[scd.cartridge.boot + 0x02].write16 = m68k.memory_map[scd.cartridge.boot + 0x03].write16 = m68k_unused_16_w;
zbank_memory_map[scd.cartridge.boot + 0x02].read = zbank_memory_map[scd.cartridge.boot + 0x03].read = zbank_unused_r;
zbank_memory_map[scd.cartridge.boot + 0x02].write = zbank_memory_map[scd.cartridge.boot + 0x03].write = zbank_unused_w;
}
/* Word-RAM */
if (scd.regs[0x03>>1].byte.l & 0x04)
{
/* 1M Mode */
load_param(scd.word_ram, sizeof(scd.word_ram));
if (scd.regs[0x03>>1].byte.l & 0x01)
{
/* Word-RAM 1 assigned to MAIN-CPU */
for (i=scd.cartridge.boot+0x20; i<scd.cartridge.boot+0x22; i++)
{
/* Word-RAM 1 data mapped at $200000-$21FFFF */
m68k.memory_map[i].base = scd.word_ram[1] + ((i & 0x01) << 16);
m68k.memory_map[i].read8 = NULL;
m68k.memory_map[i].read16 = NULL;
m68k.memory_map[i].write8 = NULL;
m68k.memory_map[i].write16 = NULL;
zbank_memory_map[i].read = NULL;
zbank_memory_map[i].write = NULL;
}
for (i=scd.cartridge.boot+0x22; i<scd.cartridge.boot+0x24; i++)
{
/* VRAM cell image mapped at $220000-$23FFFF */
m68k.memory_map[i].read8 = cell_ram_1_read8;
m68k.memory_map[i].read16 = cell_ram_1_read16;
m68k.memory_map[i].write8 = cell_ram_1_write8;
m68k.memory_map[i].write16 = cell_ram_1_write16;
zbank_memory_map[i].read = cell_ram_1_read8;
zbank_memory_map[i].write = cell_ram_1_write8;
}
/* Word-RAM 0 assigned to SUB-CPU */
for (i=0x08; i<0x0c; i++)
{
/* DOT image mapped at $080000-$0BFFFF */
s68k.memory_map[i].read8 = dot_ram_0_read8;
s68k.memory_map[i].read16 = dot_ram_0_read16;
s68k.memory_map[i].write8 = dot_ram_0_write8;
s68k.memory_map[i].write16 = dot_ram_0_write16;
}
for (i=0x0c; i<0x0e; i++)
{
/* Word-RAM 0 data mapped at $0C0000-$0DFFFF */
s68k.memory_map[i].base = scd.word_ram[0] + ((i & 0x01) << 16);
s68k.memory_map[i].read8 = NULL;
s68k.memory_map[i].read16 = NULL;
s68k.memory_map[i].write8 = NULL;
s68k.memory_map[i].write16 = NULL;
}
}
else
{
/* Word-RAM 0 assigned to MAIN-CPU */
for (i=scd.cartridge.boot+0x20; i<scd.cartridge.boot+0x22; i++)
{
/* Word-RAM 0 data mapped at $200000-$21FFFF */
m68k.memory_map[i].base = scd.word_ram[0] + ((i & 0x01) << 16);
m68k.memory_map[i].read8 = NULL;
m68k.memory_map[i].read16 = NULL;
m68k.memory_map[i].write8 = NULL;
m68k.memory_map[i].write16 = NULL;
zbank_memory_map[i].read = NULL;
zbank_memory_map[i].write = NULL;
}
for (i=scd.cartridge.boot+0x22; i<scd.cartridge.boot+0x24; i++)
{
/* VRAM cell image mapped at $220000-$23FFFF */
m68k.memory_map[i].read8 = cell_ram_0_read8;
m68k.memory_map[i].read16 = cell_ram_0_read16;
m68k.memory_map[i].write8 = cell_ram_0_write8;
m68k.memory_map[i].write16 = cell_ram_0_write16;
zbank_memory_map[i].read = cell_ram_0_read8;
zbank_memory_map[i].write = cell_ram_0_write8;
}
/* Word-RAM 1 assigned to SUB-CPU */
for (i=0x08; i<0x0c; i++)
{
/* DOT image mapped at $080000-$0BFFFF */
s68k.memory_map[i].read8 = dot_ram_1_read8;
s68k.memory_map[i].read16 = dot_ram_1_read16;
s68k.memory_map[i].write8 = dot_ram_1_write8;
s68k.memory_map[i].write16 = dot_ram_1_write16;
}
for (i=0x0c; i<0x0e; i++)
{
/* Word-RAM 1 data mapped at $0C0000-$0DFFFF */
s68k.memory_map[i].base = scd.word_ram[1] + ((i & 0x01) << 16);
s68k.memory_map[i].read8 = NULL;
s68k.memory_map[i].read16 = NULL;
s68k.memory_map[i].write8 = NULL;
s68k.memory_map[i].write16 = NULL;
}
}
}
else
{
/* 2M mode */
load_param(scd.word_ram_2M, sizeof(scd.word_ram_2M));
/* check RET bit */
if (scd.regs[0x03>>1].byte.l & 0x01)
{
/* MAIN-CPU: $200000-$23FFFF is mapped to 256K Word-RAM */
for (i=scd.cartridge.boot+0x20; i<scd.cartridge.boot+0x24; i++)
{
m68k.memory_map[i].base = scd.word_ram_2M + ((i & 0x03) << 16);
m68k.memory_map[i].read8 = NULL;
m68k.memory_map[i].read16 = NULL;
m68k.memory_map[i].write8 = NULL;
m68k.memory_map[i].write16 = NULL;
zbank_memory_map[i].read = NULL;
zbank_memory_map[i].write = NULL;
}
/* SUB-CPU: access to Word-RAM at $080000-$0BFFFF is locked (/DTACK not asserted) */
for (i=0x08; i<0x0c; i++)
{
s68k.memory_map[i].read8 = s68k_lockup_r_8;
s68k.memory_map[i].read16 = s68k_lockup_r_16;
s68k.memory_map[i].write8 = s68k_lockup_w_8;
s68k.memory_map[i].write16 = s68k_lockup_w_16;
}
}
else
{
/* MAIN-CPU: $200000-$23FFFF is unmapped */
for (i=scd.cartridge.boot+0x20; i<scd.cartridge.boot+0x24; i++)
{
m68k.memory_map[i].base = scd.word_ram_2M + ((i & 0x03) << 16);
m68k.memory_map[i].read8 = m68k_read_bus_8;
m68k.memory_map[i].read16 = m68k_read_bus_16;
m68k.memory_map[i].write8 = m68k_unused_8_w;
m68k.memory_map[i].write16 = m68k_unused_16_w;
zbank_memory_map[i].read = zbank_unused_r;
zbank_memory_map[i].write = zbank_unused_w;
}
/* SUB-CPU: access to Word-RAM at $080000-$0BFFFF is unlocked (/DTACK asserted) */
for (i=0x08; i<0x0c; i++)
{
s68k.memory_map[i].read8 = NULL;
s68k.memory_map[i].read16 = NULL;
s68k.memory_map[i].write8 = NULL;
s68k.memory_map[i].write16 = NULL;
}
}
/* SUB-CPU: $0C0000-$0DFFFF is unmapped */
for (i=0x0c; i<0x0e; i++)
{
s68k.memory_map[i].read8 = s68k_read_bus_8;
s68k.memory_map[i].read16 = s68k_read_bus_16;
s68k.memory_map[i].write8 = s68k_unused_8_w;
s68k.memory_map[i].write16 = s68k_unused_16_w;
}
}
/* MAIN-CPU & SUB-CPU polling */
load_param(&m68k.poll, sizeof(m68k.poll));
load_param(&s68k.poll, sizeof(s68k.poll));
/* H-INT default vector */
load_param(&tmp16, 2);
*(uint16 *)(m68k.memory_map[scd.cartridge.boot].base + 0x72) = tmp16;
/* SUB-CPU registers */
load_param(&tmp32, 4); s68k_set_reg(M68K_REG_D0, tmp32);
load_param(&tmp32, 4); s68k_set_reg(M68K_REG_D1, tmp32);
load_param(&tmp32, 4); s68k_set_reg(M68K_REG_D2, tmp32);
load_param(&tmp32, 4); s68k_set_reg(M68K_REG_D3, tmp32);
load_param(&tmp32, 4); s68k_set_reg(M68K_REG_D4, tmp32);
load_param(&tmp32, 4); s68k_set_reg(M68K_REG_D5, tmp32);
load_param(&tmp32, 4); s68k_set_reg(M68K_REG_D6, tmp32);
load_param(&tmp32, 4); s68k_set_reg(M68K_REG_D7, tmp32);
load_param(&tmp32, 4); s68k_set_reg(M68K_REG_A0, tmp32);
load_param(&tmp32, 4); s68k_set_reg(M68K_REG_A1, tmp32);
load_param(&tmp32, 4); s68k_set_reg(M68K_REG_A2, tmp32);
load_param(&tmp32, 4); s68k_set_reg(M68K_REG_A3, tmp32);
load_param(&tmp32, 4); s68k_set_reg(M68K_REG_A4, tmp32);
load_param(&tmp32, 4); s68k_set_reg(M68K_REG_A5, tmp32);
load_param(&tmp32, 4); s68k_set_reg(M68K_REG_A6, tmp32);
load_param(&tmp32, 4); s68k_set_reg(M68K_REG_A7, tmp32);
load_param(&tmp32, 4); s68k_set_reg(M68K_REG_PC, tmp32);
load_param(&tmp16, 2); s68k_set_reg(M68K_REG_SR, tmp16);
load_param(&tmp32, 4); s68k_set_reg(M68K_REG_USP,tmp32);
load_param(&tmp32, 4); s68k_set_reg(M68K_REG_ISP,tmp32);
/* SUB-CPU internal state */
load_param(&s68k.cycles, sizeof(s68k.cycles));
load_param(&s68k.int_level, sizeof(s68k.int_level));
load_param(&s68k.stopped, sizeof(s68k.stopped));
/* bootable MD cartridge hardware */
if (scd.cartridge.boot)
{
bufferptr += md_cart_context_load(&state[bufferptr]);
}
return bufferptr;
}
int scd_68k_irq_ack(int level)
{
#ifdef LOG_SCD
error("INT ack level %d (%X)\n", level, s68k.pc);
#endif
/* clear pending interrupt flag */
scd.pending &= ~(1 << level);
/* level 2 interrupt acknowledge */
if (level == 2)
{
/* clear IFL2 flag */
scd.regs[0x00].byte.h &= ~0x01;
}
/* update IRQ level */
s68k_update_irq((scd.pending & scd.regs[0x32>>1].byte.l) >> 1);
return M68K_INT_ACK_AUTOVECTOR;
}
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