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https://github.com/ekeeke/Genesis-Plus-GX.git
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1287 lines
33 KiB
C
1287 lines
33 KiB
C
/***************************************************************************************
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* Genesis Plus
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* Main 68k bus handlers
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*
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* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003 Charles Mac Donald (original code)
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* Copyright (C) 2007-2013 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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#include "shared.h"
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/*--------------------------------------------------------------------------*/
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/* Unused areas (return open bus data, i.e prefetched instruction word) */
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/*--------------------------------------------------------------------------*/
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unsigned int m68k_read_bus_8(unsigned int address)
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{
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#ifdef LOGERROR
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error("Unused read8 %08X (%08X)\n", address, m68k_get_reg(M68K_REG_PC));
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#endif
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address = m68k.pc | (address & 1);
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return READ_BYTE(m68k.memory_map[((address)>>16)&0xff].base, (address) & 0xffff);
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}
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unsigned int m68k_read_bus_16(unsigned int address)
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{
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#ifdef LOGERROR
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error("Unused read16 %08X (%08X)\n", address, m68k_get_reg(M68K_REG_PC));
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#endif
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address = m68k.pc;
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return *(uint16 *)(m68k.memory_map[((address)>>16)&0xff].base + ((address) & 0xffff));
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}
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void m68k_unused_8_w(unsigned int address, unsigned int data)
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{
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#ifdef LOGERROR
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error("Unused write8 %08X = %02X (%08X)\n", address, data, m68k_get_reg(M68K_REG_PC));
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#endif
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}
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void m68k_unused_16_w(unsigned int address, unsigned int data)
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{
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#ifdef LOGERROR
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error("Unused write16 %08X = %04X (%08X)\n", address, data, m68k_get_reg(M68K_REG_PC));
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#endif
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}
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/*--------------------------------------------------------------------------*/
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/* Illegal areas (cause system to lock-up since !DTACK is not returned) */
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/*--------------------------------------------------------------------------*/
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void m68k_lockup_w_8 (unsigned int address, unsigned int data)
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{
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#ifdef LOGERROR
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error ("Lockup %08X = %02X (%08X)\n", address, data, m68k_get_reg(M68K_REG_PC));
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#endif
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if (!config.force_dtack)
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{
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m68k_pulse_halt();
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m68k.cycles = m68k.cycle_end;
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}
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}
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void m68k_lockup_w_16 (unsigned int address, unsigned int data)
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{
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#ifdef LOGERROR
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error ("Lockup %08X = %04X (%08X)\n", address, data, m68k_get_reg(M68K_REG_PC));
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#endif
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if (!config.force_dtack)
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{
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m68k_pulse_halt();
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m68k.cycles = m68k.cycle_end;
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}
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}
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unsigned int m68k_lockup_r_8 (unsigned int address)
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{
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#ifdef LOGERROR
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error ("Lockup %08X.b (%08X)\n", address, m68k_get_reg(M68K_REG_PC));
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#endif
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if (!config.force_dtack)
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{
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m68k_pulse_halt();
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m68k.cycles = m68k.cycle_end;
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}
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address = m68k.pc | (address & 1);
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return READ_BYTE(m68k.memory_map[((address)>>16)&0xff].base, (address) & 0xffff);
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}
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unsigned int m68k_lockup_r_16 (unsigned int address)
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{
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#ifdef LOGERROR
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error ("Lockup %08X.w (%08X)\n", address, m68k_get_reg(M68K_REG_PC));
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#endif
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if (!config.force_dtack)
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{
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m68k_pulse_halt();
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m68k.cycles = m68k.cycle_end;
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}
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address = m68k.pc;
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return *(uint16 *)(m68k.memory_map[((address)>>16)&0xff].base + ((address) & 0xffff));
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}
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/*--------------------------------------------------------------------------*/
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/* Z80 bus (accessed through I/O chip) */
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/*--------------------------------------------------------------------------*/
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unsigned int z80_read_byte(unsigned int address)
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{
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switch ((address >> 13) & 3)
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{
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case 2: /* YM2612 */
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{
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return fm_read(m68k.cycles, address & 3);
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}
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case 3: /* Misc */
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{
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/* VDP (through 68k bus) */
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if ((address & 0xFF00) == 0x7F00)
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{
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return m68k_lockup_r_8(address);
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}
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return (m68k_read_bus_8(address) | 0xFF);
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}
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default: /* ZRAM */
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{
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return zram[address & 0x1FFF];
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}
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}
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}
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unsigned int z80_read_word(unsigned int address)
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{
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unsigned int data = z80_read_byte(address);
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return (data | (data << 8));
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}
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void z80_write_byte(unsigned int address, unsigned int data)
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{
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switch ((address >> 13) & 3)
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{
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case 2: /* YM2612 */
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{
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fm_write(m68k.cycles, address & 3, data);
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return;
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}
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case 3:
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{
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switch ((address >> 8) & 0x7F)
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{
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case 0x60: /* Bank register */
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{
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gen_zbank_w(data & 1);
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return;
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}
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case 0x7F: /* VDP */
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{
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m68k_lockup_w_8(address, data);
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return;
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}
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default:
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{
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m68k_unused_8_w(address, data);
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return;
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}
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}
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}
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default: /* ZRAM */
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{
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zram[address & 0x1FFF] = data;
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m68k.cycles += 8; /* ZRAM access latency (fixes Pacman 2: New Adventures) */
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return;
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}
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}
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}
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void z80_write_word(unsigned int address, unsigned int data)
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{
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z80_write_byte(address, data >> 8);
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}
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/*--------------------------------------------------------------------------*/
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/* I/O Control */
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/*--------------------------------------------------------------------------*/
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static void m68k_poll_detect(unsigned int reg_mask)
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{
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/* detect MAIN-CPU register polling */
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if (m68k.poll.detected & reg_mask)
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{
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if (m68k.cycles <= m68k.poll.cycle)
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{
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if (m68k.pc == m68k.poll.pc)
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{
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/* MAIN-CPU polling confirmed ? */
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if (m68k.poll.detected & 1)
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{
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/* idle MAIN-CPU until register is modified */
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m68k.cycles = m68k.cycle_end;
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m68k.stopped = reg_mask;
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#ifdef LOG_SCD
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error("m68k stopped from %d cycles\n", m68k.cycles);
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#endif
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}
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else
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{
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/* confirm MAIN-CPU polling */
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m68k.poll.detected |= 1;
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m68k.poll.cycle = m68k.cycles + 840;
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}
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}
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return;
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}
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}
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else
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{
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/* set MAIN-CPU register access flag */
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m68k.poll.detected = reg_mask;
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}
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/* reset MAIN-CPU polling detection */
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m68k.poll.cycle = m68k.cycles + 840;
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m68k.poll.pc = m68k.pc;
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}
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static void m68k_poll_sync(unsigned int reg_mask)
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{
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/* relative SUB-CPU cycle counter */
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unsigned int cycles = (m68k.cycles * SCYCLES_PER_LINE) / MCYCLES_PER_LINE;
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/* sync SUB-CPU with MAIN-CPU */
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if (!s68k.stopped && (s68k.cycles < cycles))
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{
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s68k_run(cycles);
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}
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/* SUB-CPU idle on register polling ? */
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if (s68k.stopped & reg_mask)
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{
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/* sync SUB-CPU with MAIN-CPU */
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s68k.cycles = cycles;
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/* restart SUB-CPU */
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s68k.stopped = 0;
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#ifdef LOG_SCD
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error("s68k started from %d cycles\n", cycles);
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#endif
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}
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/* clear CPU register access flags */
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s68k.poll.detected &= ~reg_mask;
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m68k.poll.detected &= ~reg_mask;
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}
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unsigned int ctrl_io_read_byte(unsigned int address)
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{
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switch ((address >> 8) & 0xFF)
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{
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case 0x00: /* I/O chip */
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{
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if (!(address & 0xE0))
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{
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return io_68k_read((address >> 1) & 0x0F);
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}
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return m68k_read_bus_8(address);
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}
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case 0x11: /* Z80 BUSACK */
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{
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if (!(address & 1))
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{
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/* Unused bits return prefetched bus data (Time Killers) */
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address = m68k.pc;
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/* Check if bus has been requested and is not reseted */
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if (zstate == 3)
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{
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/* D0 is cleared */
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return (READ_BYTE(m68k.memory_map[((address)>>16)&0xff].base, (address) & 0xffff) & 0xFE);
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}
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/* D0 is set */
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return (READ_BYTE(m68k.memory_map[((address)>>16)&0xff].base, (address) & 0xffff) | 0x01);
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}
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return m68k_read_bus_8(address);
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}
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case 0x20: /* MEGA-CD */
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{
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#ifdef LOG_SCD
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error("[%d][%d]read byte CD register %X (%X)\n", v_counter, m68k.cycles, address, m68k.pc);
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#endif
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if (system_hw == SYSTEM_MCD)
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{
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/* register index ($A12000-A1203F mirrored up to $A120FF) */
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uint8 index = address & 0x3f;
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/* Memory Mode */
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if (index == 0x03)
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{
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m68k_poll_detect(1<<0x03);
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return scd.regs[0x03>>1].byte.l;
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}
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/* SUB-CPU communication flags */
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if (index == 0x0f)
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{
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/* relative SUB-CPU cycle counter */
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unsigned int cycles = (m68k.cycles * SCYCLES_PER_LINE) / MCYCLES_PER_LINE;
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/* sync SUB-CPU with MAIN-CPU (Dracula Unleashed w/ Sega CD Model 2 Boot ROM) */
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if (!s68k.stopped && (s68k.cycles < cycles))
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{
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s68k_run(cycles);
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}
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m68k_poll_detect(1<<0x0f);
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return scd.regs[0x0f>>1].byte.l;
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}
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/* default registers */
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if (index < 0x30)
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{
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/* SUB-CPU communication words */
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if (index >= 0x20)
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{
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m68k_poll_detect(1 << (index - 0x10));
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}
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/* register LSB */
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if (address & 1)
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{
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return scd.regs[index >> 1].byte.l;
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}
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/* register MSB */
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return scd.regs[index >> 1].byte.h;
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}
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}
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return m68k_read_bus_8(address);
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}
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case 0x30: /* TIME */
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{
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if (cart.hw.time_r)
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{
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unsigned int data = cart.hw.time_r(address);
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if (address & 1)
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{
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return (data & 0xFF);
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}
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return (data >> 8);
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}
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return m68k_read_bus_8(address);
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}
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case 0x41: /* BOOT ROM */
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{
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if ((config.bios & 1) && (address & 1))
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{
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unsigned int data = gen_bankswitch_r() & 1;
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/* Unused bits return prefetched bus data */
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address = m68k.pc;
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data |= (READ_BYTE(m68k.memory_map[((address)>>16)&0xff].base, (address) & 0xffff) & 0xFE);
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return data;
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}
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return m68k_read_bus_8(address);
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}
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case 0x10: /* MEMORY MODE */
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case 0x12: /* Z80 RESET */
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case 0x13: /* unknown */
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case 0x40: /* TMSS */
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case 0x44: /* RADICA */
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case 0x50: /* SVP */
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{
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return m68k_read_bus_8(address);
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}
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default: /* Invalid address */
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{
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return m68k_lockup_r_8(address);
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}
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}
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}
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unsigned int ctrl_io_read_word(unsigned int address)
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{
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switch ((address >> 8) & 0xFF)
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{
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case 0x00: /* I/O chip */
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{
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if (!(address & 0xE0))
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{
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unsigned int data = io_68k_read((address >> 1) & 0x0F);
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return (data << 8 | data);
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}
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return m68k_read_bus_16(address);
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}
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case 0x11: /* Z80 BUSACK */
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{
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/* Unused bits return prefetched bus data (Time Killers) */
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address = m68k.pc;
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/* Check if bus has been requested and is not reseted */
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if (zstate == 3)
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{
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/* D8 is cleared */
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return (*(uint16 *)(m68k.memory_map[((address)>>16)&0xff].base + ((address) & 0xffff)) & 0xFEFF);
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}
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/* D8 is set */
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return (*(uint16 *)(m68k.memory_map[((address)>>16)&0xff].base + ((address) & 0xffff)) | 0x0100);
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}
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case 0x20: /* MEGA-CD */
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{
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#ifdef LOG_SCD
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error("[%d][%d]read word CD register %X (%X)\n", v_counter, m68k.cycles, address, m68k.pc);
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#endif
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if (system_hw == SYSTEM_MCD)
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{
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/* register index ($A12000-A1203F mirrored up to $A120FF) */
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uint8 index = address & 0x3f;
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/* Memory Mode */
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if (index == 0x02)
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{
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m68k_poll_detect(1<<0x03);
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return scd.regs[0x03>>1].w;
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}
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/* CDC host data (word access only ?) */
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if (index == 0x08)
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{
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return cdc_host_r();
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}
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/* H-INT vector (word access only ?) */
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if (index == 0x06)
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{
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return *(uint16 *)(m68k.memory_map[0].base + 0x72);
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}
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/* Stopwatch counter (word read access only ?) */
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if (index == 0x0c)
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{
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/* relative SUB-CPU cycle counter */
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unsigned int cycles = (m68k.cycles * SCYCLES_PER_LINE) / MCYCLES_PER_LINE;
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/* cycle-accurate counter value */
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return (scd.regs[0x0c>>1].w + ((cycles - scd.stopwatch) / TIMERS_SCYCLES_RATIO)) & 0xfff;
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}
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/* default registers */
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if (index < 0x30)
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{
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/* relative SUB-CPU cycle counter */
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unsigned int cycles = (m68k.cycles * SCYCLES_PER_LINE) / MCYCLES_PER_LINE;
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/* sync SUB-CPU with MAIN-CPU (Soul Star) */
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if (!s68k.stopped && (s68k.cycles < cycles))
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{
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s68k_run(cycles);
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}
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/* SUB-CPU communication words */
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if (index >= 0x20)
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{
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m68k_poll_detect(3 << (index - 0x10));
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}
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return scd.regs[index >> 1].w;
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}
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}
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|
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/* invalid address */
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return m68k_read_bus_16(address);
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}
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|
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case 0x30: /* TIME */
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{
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if (cart.hw.time_r)
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{
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return cart.hw.time_r(address);
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}
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return m68k_read_bus_16(address);
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}
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|
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case 0x50: /* SVP */
|
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{
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if ((address & 0xFD) == 0)
|
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{
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return svp->ssp1601.gr[SSP_XST].byte.h;
|
|
}
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|
|
if ((address & 0xFF) == 4)
|
|
{
|
|
unsigned int data = svp->ssp1601.gr[SSP_PM0].byte.h;
|
|
svp->ssp1601.gr[SSP_PM0].byte.h &= ~1;
|
|
return data;
|
|
}
|
|
|
|
return m68k_read_bus_16(address);
|
|
}
|
|
|
|
case 0x10: /* MEMORY MODE */
|
|
case 0x12: /* Z80 RESET */
|
|
case 0x13: /* unknown */
|
|
case 0x40: /* TMSS */
|
|
case 0x41: /* BOOT ROM */
|
|
case 0x44: /* RADICA */
|
|
{
|
|
return m68k_read_bus_16(address);
|
|
}
|
|
|
|
default: /* Invalid address */
|
|
{
|
|
return m68k_lockup_r_16(address);
|
|
}
|
|
}
|
|
}
|
|
|
|
void ctrl_io_write_byte(unsigned int address, unsigned int data)
|
|
{
|
|
switch ((address >> 8) & 0xFF)
|
|
{
|
|
case 0x00: /* I/O chip */
|
|
{
|
|
if ((address & 0xE1) == 0x01)
|
|
{
|
|
/* get /LWR only */
|
|
io_68k_write((address >> 1) & 0x0F, data);
|
|
return;
|
|
}
|
|
m68k_unused_8_w(address, data);
|
|
return;
|
|
}
|
|
|
|
case 0x11: /* Z80 BUSREQ */
|
|
{
|
|
if (!(address & 1))
|
|
{
|
|
gen_zbusreq_w(data & 1, m68k.cycles);
|
|
return;
|
|
}
|
|
m68k_unused_8_w(address, data);
|
|
return;
|
|
}
|
|
|
|
case 0x12: /* Z80 RESET */
|
|
{
|
|
if (!(address & 1))
|
|
{
|
|
gen_zreset_w(data & 1, m68k.cycles);
|
|
return;
|
|
}
|
|
m68k_unused_8_w(address, data);
|
|
return;
|
|
}
|
|
|
|
case 0x20: /* MEGA-CD */
|
|
{
|
|
#ifdef LOG_SCD
|
|
error("[%d][%d]write byte CD register %X -> 0x%02X (%X)\n", v_counter, m68k.cycles, address, data, m68k.pc);
|
|
#endif
|
|
if (system_hw == SYSTEM_MCD)
|
|
{
|
|
/* register index ($A12000-A1203F mirrored up to $A120FF) */
|
|
switch (address & 0x3f)
|
|
{
|
|
case 0x00: /* SUB-CPU interrupt */
|
|
{
|
|
/* IFL2 bit */
|
|
if (data & 0x01)
|
|
{
|
|
/* level 2 interrupt enabled ? */
|
|
if (scd.regs[0x32>>1].byte.l & 0x04)
|
|
{
|
|
/* relative SUB-CPU cycle counter */
|
|
unsigned int cycles = (m68k.cycles * SCYCLES_PER_LINE) / MCYCLES_PER_LINE;
|
|
|
|
/* sync SUB-CPU with MAIN-CPU (Earnest Evans, Fhey Area) */
|
|
if (!s68k.stopped && (s68k.cycles < cycles))
|
|
{
|
|
s68k_run(cycles);
|
|
}
|
|
|
|
/* set IFL2 flag */
|
|
scd.regs[0x00].byte.h |= 0x01;
|
|
|
|
/* trigger level 2 interrupt */
|
|
scd.pending |= (1 << 2);
|
|
|
|
/* update IRQ level */
|
|
s68k_update_irq((scd.pending & scd.regs[0x32>>1].byte.l) >> 1);
|
|
}
|
|
}
|
|
|
|
/* writing 0 does nothing */
|
|
return;
|
|
}
|
|
|
|
case 0x01: /* SUB-CPU control */
|
|
{
|
|
/* RESET bit */
|
|
if (data & 0x01)
|
|
{
|
|
/* trigger reset on 0->1 transition */
|
|
if (!(scd.regs[0x00].byte.l & 0x01))
|
|
{
|
|
/* reset SUB-CPU */
|
|
s68k_pulse_reset();
|
|
}
|
|
|
|
/* BUSREQ bit */
|
|
if (data & 0x02)
|
|
{
|
|
/* SUB-CPU bus requested */
|
|
s68k_pulse_halt();
|
|
}
|
|
else
|
|
{
|
|
/* SUB-CPU bus released */
|
|
s68k_clear_halt();
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* SUB-CPU is halted while !RESET is asserted */
|
|
s68k_pulse_halt();
|
|
}
|
|
|
|
scd.regs[0x00].byte.l = data;
|
|
return;
|
|
}
|
|
|
|
case 0x02: /* PRG-RAM Write Protection */
|
|
{
|
|
scd.regs[0x02>>1].byte.h = data;
|
|
return;
|
|
}
|
|
|
|
case 0x03: /* Memory mode */
|
|
{
|
|
m68k_poll_sync(1<<0x03);
|
|
|
|
/* PRG-RAM 128k bank mapped to $020000-$03FFFF (resp. $420000-$43FFFF) */
|
|
m68k.memory_map[scd.cartridge.boot + 0x02].base = scd.prg_ram + ((data & 0xc0) << 11);
|
|
m68k.memory_map[scd.cartridge.boot + 0x03].base = m68k.memory_map[scd.cartridge.boot + 0x02].base + 0x10000;
|
|
|
|
/* check current mode */
|
|
if (scd.regs[0x03>>1].byte.l & 0x04)
|
|
{
|
|
/* DMNA bit */
|
|
if (data & 0x02)
|
|
{
|
|
/* writing 1 to DMNA in 1M mode will return Word-RAM to SUB-CPU in 2M mode */
|
|
scd.dmna = 1;
|
|
}
|
|
else
|
|
{
|
|
/* writing 0 to DMNA in 1M mode actually set DMNA bit */
|
|
data |= 0x02;
|
|
|
|
/* update BK0-1 & DMNA bits */
|
|
scd.regs[0x03>>1].byte.l = (scd.regs[0x03>>1].byte.l & ~0xc2) | (data & 0xc2);
|
|
return;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* writing 0 in 2M mode does nothing */
|
|
if (data & 0x02)
|
|
{
|
|
/* Word-RAM is assigned to SUB-CPU */
|
|
scd.dmna = 1;
|
|
|
|
/* clear RET bit */
|
|
scd.regs[0x03>>1].byte.l = (scd.regs[0x03>>1].byte.l & ~0xc3) | (data & 0xc2);
|
|
return;
|
|
}
|
|
}
|
|
|
|
/* update BK0-1 bits */
|
|
scd.regs[0x03>>1].byte.l = (scd.regs[0x02>>1].byte.l & ~0xc0) | (data & 0xc0);
|
|
return;
|
|
}
|
|
|
|
case 0x0f: /* SUB-CPU communication flags, normally read-only (Space Ace, Dragon's Lair) */
|
|
{
|
|
/* ROL8 operation */
|
|
data = (data << 1) | ((data >> 7) & 1);
|
|
}
|
|
|
|
case 0x0e: /* MAIN-CPU communication flags */
|
|
{
|
|
m68k_poll_sync(1<<0x0e);
|
|
scd.regs[0x0e>>1].byte.h = data;
|
|
return;
|
|
}
|
|
|
|
default:
|
|
{
|
|
/* MAIN-CPU communication words */
|
|
if ((address & 0x30) == 0x10)
|
|
{
|
|
m68k_poll_sync(1 << (address & 0x1f));
|
|
|
|
/* register LSB */
|
|
if (address & 1)
|
|
{
|
|
scd.regs[(address >> 1) & 0xff].byte.l = data;
|
|
return;
|
|
}
|
|
|
|
/* register MSB */
|
|
scd.regs[(address >> 1) & 0xff].byte.h = data;
|
|
return;
|
|
}
|
|
|
|
/* invalid address */
|
|
m68k_unused_8_w(address, data);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
m68k_unused_8_w(address, data);
|
|
return;
|
|
}
|
|
|
|
case 0x30: /* TIME */
|
|
{
|
|
cart.hw.time_w(address, data);
|
|
return;
|
|
}
|
|
|
|
case 0x41: /* BOOT ROM */
|
|
{
|
|
if ((config.bios & 1) && (address & 1))
|
|
{
|
|
gen_bankswitch_w(data & 1);
|
|
return;
|
|
}
|
|
m68k_unused_8_w(address, data);
|
|
return;
|
|
}
|
|
|
|
case 0x10: /* MEMORY MODE */
|
|
case 0x13: /* unknown */
|
|
case 0x40: /* TMSS */
|
|
case 0x44: /* RADICA */
|
|
case 0x50: /* SVP */
|
|
{
|
|
m68k_unused_8_w(address, data);
|
|
return;
|
|
}
|
|
|
|
default: /* Invalid address */
|
|
{
|
|
m68k_lockup_w_8(address, data);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
void ctrl_io_write_word(unsigned int address, unsigned int data)
|
|
{
|
|
switch ((address >> 8) & 0xFF)
|
|
{
|
|
case 0x00: /* I/O chip */
|
|
{
|
|
if (!(address & 0xE0))
|
|
{
|
|
io_68k_write((address >> 1) & 0x0F, data & 0xFF);
|
|
return;
|
|
}
|
|
m68k_unused_16_w(address, data);
|
|
return;
|
|
}
|
|
|
|
case 0x11: /* Z80 BUSREQ */
|
|
{
|
|
gen_zbusreq_w((data >> 8) & 1, m68k.cycles);
|
|
return;
|
|
}
|
|
|
|
case 0x12: /* Z80 RESET */
|
|
{
|
|
gen_zreset_w((data >> 8) & 1, m68k.cycles);
|
|
return;
|
|
}
|
|
|
|
case 0x20: /* MEGA-CD */
|
|
{
|
|
#ifdef LOG_SCD
|
|
error("[%d][%d]write word CD register %X -> 0x%04X (%X)\n", v_counter, m68k.cycles, address, data, m68k.pc);
|
|
#endif
|
|
if (system_hw == SYSTEM_MCD)
|
|
{
|
|
/* register index ($A12000-A1203F mirrored up to $A120FF) */
|
|
switch (address & 0x3e)
|
|
{
|
|
case 0x00: /* SUB-CPU interrupt & control */
|
|
{
|
|
/* RESET bit */
|
|
if (data & 0x01)
|
|
{
|
|
/* trigger reset on 0->1 transition */
|
|
if (!(scd.regs[0x00].byte.l & 0x01))
|
|
{
|
|
/* reset SUB-CPU */
|
|
s68k_pulse_reset();
|
|
}
|
|
|
|
/* BUSREQ bit */
|
|
if (data & 0x02)
|
|
{
|
|
/* SUB-CPU bus requested */
|
|
s68k_pulse_halt();
|
|
}
|
|
else
|
|
{
|
|
/* SUB-CPU bus released */
|
|
s68k_clear_halt();
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* SUB-CPU is halted while !RESET is asserted */
|
|
s68k_pulse_halt();
|
|
}
|
|
|
|
/* IFL2 bit */
|
|
if (data & 0x100)
|
|
{
|
|
/* level 2 interrupt enabled ? */
|
|
if (scd.regs[0x32>>1].byte.l & 0x04)
|
|
{
|
|
/* set IFL2 flag */
|
|
scd.regs[0x00].byte.h |= 0x01;
|
|
|
|
/* trigger level 2 interrupt */
|
|
scd.pending |= (1 << 2);
|
|
|
|
/* update IRQ level */
|
|
s68k_update_irq((scd.pending & scd.regs[0x32>>1].byte.l) >> 1);
|
|
}
|
|
}
|
|
|
|
/* update LSB only */
|
|
scd.regs[0x00].byte.l = data & 0xff;
|
|
return;
|
|
}
|
|
|
|
case 0x02: /* Memory Mode */
|
|
{
|
|
m68k_poll_sync(1<<0x03);
|
|
|
|
/* PRG-RAM 128k bank mapped to $020000-$03FFFF (resp. $420000-$43FFFF) */
|
|
m68k.memory_map[scd.cartridge.boot + 0x02].base = scd.prg_ram + ((data & 0xc0) << 11);
|
|
m68k.memory_map[scd.cartridge.boot + 0x03].base = m68k.memory_map[scd.cartridge.boot + 0x02].base + 0x10000;
|
|
|
|
/* check current mode */
|
|
if (scd.regs[0x03>>1].byte.l & 0x04)
|
|
{
|
|
/* DMNA bit */
|
|
if (data & 0x02)
|
|
{
|
|
/* writing 1 to DMNA in 1M mode will return Word-RAM to SUB-CPU in 2M mode */
|
|
scd.dmna = 1;
|
|
}
|
|
else
|
|
{
|
|
/* writing 0 to DMNA in 1M mode actually set DMNA bit */
|
|
data |= 0x02;
|
|
|
|
/* update WP0-7, BK0-1 & DMNA bits */
|
|
scd.regs[0x02>>1].w = (scd.regs[0x02>>1].w & ~0xffc2) | (data & 0xffc2);
|
|
return;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
/* writing 0 in 2M mode does nothing */
|
|
if (data & 0x02)
|
|
{
|
|
/* Word-RAM is assigned to SUB-CPU */
|
|
scd.dmna = 1;
|
|
|
|
/* clear RET bit */
|
|
scd.regs[0x02>>1].w = (scd.regs[0x02>>1].w & ~0xffc3) | (data & 0xffc2);
|
|
return;
|
|
}
|
|
}
|
|
|
|
/* update WP0-7 & BK0-1 bits */
|
|
scd.regs[0x02>>1].w = (scd.regs[0x02>>1].w & ~0xffc0) | (data & 0xffc0);
|
|
return;
|
|
}
|
|
|
|
case 0x06: /* H-INT vector (word access only ?) */
|
|
{
|
|
*(uint16 *)(m68k.memory_map[0].base + 0x72) = data;
|
|
return;
|
|
}
|
|
|
|
case 0x0e: /* MAIN-CPU communication flags */
|
|
{
|
|
m68k_poll_sync(1<<0x0e);
|
|
|
|
/* LSB is read-only (Mortal Kombat) */
|
|
scd.regs[0x0e>>1].byte.h = data;
|
|
return;
|
|
}
|
|
|
|
default:
|
|
{
|
|
/* MAIN-CPU communication words */
|
|
if ((address & 0x30) == 0x10)
|
|
{
|
|
m68k_poll_sync(3 << (address & 0x1e));
|
|
scd.regs[(address >> 1) & 0xff].w = data;
|
|
return;
|
|
}
|
|
|
|
/* invalid address */
|
|
m68k_unused_16_w (address, data);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
m68k_unused_16_w (address, data);
|
|
return;
|
|
}
|
|
|
|
case 0x30: /* TIME */
|
|
{
|
|
cart.hw.time_w(address, data);
|
|
return;
|
|
}
|
|
|
|
case 0x40: /* TMSS */
|
|
{
|
|
if (config.bios & 1)
|
|
{
|
|
gen_tmss_w(address & 3, data);
|
|
return;
|
|
}
|
|
m68k_unused_16_w(address, data);
|
|
return;
|
|
}
|
|
|
|
case 0x50: /* SVP */
|
|
{
|
|
if (!(address & 0xFD))
|
|
{
|
|
svp->ssp1601.gr[SSP_XST].byte.h = data;
|
|
svp->ssp1601.gr[SSP_PM0].byte.h |= 2;
|
|
svp->ssp1601.emu_status &= ~SSP_WAIT_PM0;
|
|
return;
|
|
}
|
|
m68k_unused_16_w(address, data);
|
|
return;
|
|
}
|
|
|
|
case 0x10: /* MEMORY MODE */
|
|
case 0x13: /* unknown */
|
|
case 0x41: /* BOOT ROM */
|
|
case 0x44: /* RADICA */
|
|
{
|
|
m68k_unused_16_w (address, data);
|
|
return;
|
|
}
|
|
|
|
default: /* Invalid address */
|
|
{
|
|
m68k_lockup_w_16 (address, data);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/*--------------------------------------------------------------------------*/
|
|
/* VDP */
|
|
/*--------------------------------------------------------------------------*/
|
|
|
|
unsigned int vdp_read_byte(unsigned int address)
|
|
{
|
|
switch (address & 0xFD)
|
|
{
|
|
case 0x00: /* DATA */
|
|
{
|
|
return (vdp_68k_data_r() >> 8);
|
|
}
|
|
|
|
case 0x01: /* DATA */
|
|
{
|
|
return (vdp_68k_data_r() & 0xFF);
|
|
}
|
|
|
|
case 0x04: /* CTRL */
|
|
{
|
|
unsigned int data = (vdp_68k_ctrl_r(m68k.cycles) >> 8) & 3;
|
|
|
|
/* Unused bits return prefetched bus data */
|
|
address = m68k.pc;
|
|
data |= (READ_BYTE(m68k.memory_map[((address)>>16)&0xff].base, (address) & 0xffff) & 0xFC);
|
|
|
|
return data;
|
|
}
|
|
|
|
case 0x05: /* CTRL */
|
|
{
|
|
return (vdp_68k_ctrl_r(m68k.cycles) & 0xFF);
|
|
}
|
|
|
|
case 0x08: /* HVC */
|
|
case 0x0C:
|
|
{
|
|
return (vdp_hvc_r(m68k.cycles) >> 8);
|
|
}
|
|
|
|
case 0x09: /* HVC */
|
|
case 0x0D:
|
|
{
|
|
return (vdp_hvc_r(m68k.cycles) & 0xFF);
|
|
}
|
|
|
|
case 0x18: /* Unused */
|
|
case 0x19:
|
|
case 0x1C:
|
|
case 0x1D:
|
|
{
|
|
return m68k_read_bus_8(address);
|
|
}
|
|
|
|
default: /* Invalid address */
|
|
{
|
|
return m68k_lockup_r_8(address);
|
|
}
|
|
}
|
|
}
|
|
|
|
unsigned int vdp_read_word(unsigned int address)
|
|
{
|
|
switch (address & 0xFC)
|
|
{
|
|
case 0x00: /* DATA */
|
|
{
|
|
return vdp_68k_data_r();
|
|
}
|
|
|
|
case 0x04: /* CTRL */
|
|
{
|
|
unsigned int data = vdp_68k_ctrl_r(m68k.cycles) & 0x3FF;
|
|
|
|
/* Unused bits return prefetched bus data */
|
|
address = m68k.pc;
|
|
data |= (*(uint16 *)(m68k.memory_map[((address)>>16)&0xff].base + ((address) & 0xffff)) & 0xFC00);
|
|
|
|
return data;
|
|
}
|
|
|
|
case 0x08: /* HVC */
|
|
case 0x0C:
|
|
{
|
|
return vdp_hvc_r(m68k.cycles);
|
|
}
|
|
|
|
case 0x18: /* Unused */
|
|
case 0x1C:
|
|
{
|
|
return m68k_read_bus_16(address);
|
|
}
|
|
|
|
default: /* Invalid address */
|
|
{
|
|
return m68k_lockup_r_16(address);
|
|
}
|
|
}
|
|
}
|
|
|
|
void vdp_write_byte(unsigned int address, unsigned int data)
|
|
{
|
|
switch (address & 0xFC)
|
|
{
|
|
case 0x00: /* Data port */
|
|
{
|
|
vdp_68k_data_w(data << 8 | data);
|
|
return;
|
|
}
|
|
|
|
case 0x04: /* Control port */
|
|
{
|
|
vdp_68k_ctrl_w(data << 8 | data);
|
|
return;
|
|
}
|
|
|
|
case 0x10: /* PSG */
|
|
case 0x14:
|
|
{
|
|
if (address & 1)
|
|
{
|
|
SN76489_Write(m68k.cycles, data);
|
|
return;
|
|
}
|
|
m68k_unused_8_w(address, data);
|
|
return;
|
|
}
|
|
|
|
case 0x18: /* Unused */
|
|
{
|
|
m68k_unused_8_w(address, data);
|
|
return;
|
|
}
|
|
|
|
case 0x1C: /* TEST register */
|
|
{
|
|
vdp_test_w(data << 8 | data);
|
|
return;
|
|
}
|
|
|
|
default: /* Invalid address */
|
|
{
|
|
m68k_lockup_w_8(address, data);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
void vdp_write_word(unsigned int address, unsigned int data)
|
|
{
|
|
switch (address & 0xFC)
|
|
{
|
|
case 0x00: /* DATA */
|
|
{
|
|
vdp_68k_data_w(data);
|
|
return;
|
|
}
|
|
|
|
case 0x04: /* CTRL */
|
|
{
|
|
vdp_68k_ctrl_w(data);
|
|
return;
|
|
}
|
|
|
|
case 0x10: /* PSG */
|
|
case 0x14:
|
|
{
|
|
SN76489_Write(m68k.cycles, data & 0xFF);
|
|
return;
|
|
}
|
|
|
|
case 0x18: /* Unused */
|
|
{
|
|
m68k_unused_16_w(address, data);
|
|
return;
|
|
}
|
|
|
|
case 0x1C: /* Test register */
|
|
{
|
|
vdp_test_w(data);
|
|
return;
|
|
}
|
|
|
|
default: /* Invalid address */
|
|
{
|
|
m68k_lockup_w_16 (address, data);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/*--------------------------------------------------------------------------*/
|
|
/* PICO (incomplete) */
|
|
/*--------------------------------------------------------------------------*/
|
|
|
|
unsigned int pico_read_byte(unsigned int address)
|
|
{
|
|
switch (address & 0xFF)
|
|
{
|
|
case 0x01: /* VERSION register */
|
|
{
|
|
return (region_code >> 1);
|
|
}
|
|
|
|
case 0x03: /* IO register */
|
|
{
|
|
return ~input.pad[0];
|
|
}
|
|
|
|
case 0x05: /* PEN X coordinate (MSB) */
|
|
{
|
|
return (input.analog[0][0] >> 8);
|
|
}
|
|
|
|
case 0x07: /* PEN X coordinate (LSB) */
|
|
{
|
|
return (input.analog[0][0] & 0xFF);
|
|
}
|
|
|
|
case 0x09: /* PEN Y coordinate (MSB) */
|
|
{
|
|
return (input.analog[0][1] >> 8);
|
|
}
|
|
|
|
case 0x0B: /* PEN Y coordinate (LSB) */
|
|
{
|
|
return (input.analog[0][1] & 0xFF);
|
|
}
|
|
|
|
case 0x0D: /* PAGE register */
|
|
{
|
|
return (1 << pico_current) - 1;
|
|
}
|
|
|
|
case 0x10: /* ADPCM data registers (TODO) */
|
|
case 0x11:
|
|
{
|
|
return 0xff;
|
|
}
|
|
|
|
case 0x12: /* ADPCM control registers (TODO) */
|
|
{
|
|
return 0x80;
|
|
}
|
|
|
|
default:
|
|
{
|
|
return m68k_read_bus_8(address);
|
|
}
|
|
}
|
|
}
|
|
|
|
unsigned int pico_read_word(unsigned int address)
|
|
{
|
|
return (pico_read_byte(address | 1) | (pico_read_byte(address) << 8));
|
|
}
|