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[Core/CD] disabled 68k & Z80 access to PRG-RAM when SUB-CPU is running (proper fix for Dungeon Explorer USA version)

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This commit is contained in:
EkeEke 2015-01-28 00:32:44 +01:00
parent d11e0166fa
commit e9e56c56b0
3 changed files with 85 additions and 3 deletions
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24
core/cd_hw/scd.c
View File

@ -1094,7 +1094,7 @@ void scd_init(void)
m68k.memory_map[i].write8 = NULL;
m68k.memory_map[i].write16 = NULL;
zbank_memory_map[i].read = NULL;
zbank_memory_map[i].write = zbank_unused_w; /* Z80 cannot write to PRG-RAM (Dungeon Explorer USA version) */
zbank_memory_map[i].write = NULL;
}
else
@ -1479,6 +1479,28 @@ int scd_context_load(uint8 *state)
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 when SUB-CPU is halted (Dungeon Explorer USA version) */
if ((scd.regs[0x00].byte.l & 0x03) != 0x01)
{
/* PRG-RAM (128KB bank) is mapped to $020000-$03FFFF (resp. $420000-$43FFFF) */
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
{
/* $020000-$03FFFF (resp. $420000-$43FFFF) is not mapped */
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_w_8;
m68k.memory_map[scd.cartridge.boot + 0x02].write16 = m68k.memory_map[scd.cartridge.boot + 0x03].write16 = m68k_unused_w_16;
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)
{

62
core/mem68k.c
View File

@ -3,7 +3,7 @@
* Main 68k bus handlers
*
* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003 Charles Mac Donald (original code)
* Copyright (C) 2007-2013 Eke-Eke (Genesis Plus GX)
* Copyright (C) 2007-2015 Eke-Eke (Genesis Plus GX)
*
* Redistribution and use of this code or any derivative works are permitted
* provided that the following conditions are met:
@ -646,6 +646,8 @@ void ctrl_io_write_byte(unsigned int address, unsigned int data)
case 0x01: /* SUB-CPU control */
{
unsigned int status = s68k.cpu_stopped;
/* RESET bit */
if (data & 0x01)
{
@ -674,6 +676,34 @@ void ctrl_io_write_byte(unsigned int address, unsigned int data)
s68k_pulse_halt();
}
/* check if SUB-CPU status has changed */
if (s68k.cpu_stopped != status)
{
unsigned int base = scd.cartridge.boot;
/* PRG-RAM can only be accessed from MAIN 68K & Z80 when SUB-CPU is halted (Dungeon Explorer USA version) */
if (s68k.cpu_stopped & STOP_LEVEL_HALT)
{
/* PRG-RAM (128KB bank) is mapped to $020000-$03FFFF (resp. $420000-$43FFFF) */
m68k.memory_map[base + 0x02].read8 = m68k.memory_map[base + 0x03].read8 = NULL;
m68k.memory_map[base + 0x02].read16 = m68k.memory_map[base + 0x03].read16 = NULL;
m68k.memory_map[base + 0x02].write8 = m68k.memory_map[base + 0x03].write8 = NULL;
m68k.memory_map[base + 0x02].write16 = m68k.memory_map[base + 0x03].write16 = NULL;
zbank_memory_map[base + 0x02].read = zbank_memory_map[base + 0x03].read = NULL;
zbank_memory_map[base + 0x02].write = zbank_memory_map[base + 0x03].write = NULL;
}
else
{
/* $020000-$03FFFF (resp. $420000-$43FFFF) is not mapped */
m68k.memory_map[base + 0x02].read8 = m68k.memory_map[base + 0x03].read8 = m68k_read_bus_8;
m68k.memory_map[base + 0x02].read16 = m68k.memory_map[base + 0x03].read16 = m68k_read_bus_16;
m68k.memory_map[base + 0x02].write8 = m68k.memory_map[base + 0x03].write8 = m68k_unused_w_8;
m68k.memory_map[base + 0x02].write16 = m68k.memory_map[base + 0x03].write16 = m68k_unused_w_16;
zbank_memory_map[base + 0x02].read = zbank_memory_map[base + 0x03].read = zbank_unused_r;
zbank_memory_map[base + 0x02].write = zbank_memory_map[base + 0x03].write = zbank_unused_w;
}
}
scd.regs[0x00].byte.l = data;
return;
}
@ -842,6 +872,8 @@ void ctrl_io_write_word(unsigned int address, unsigned int data)
{
case 0x00: /* SUB-CPU interrupt & control */
{
unsigned int status = s68k.cpu_stopped;
/* RESET bit */
if (data & 0x01)
{
@ -870,6 +902,34 @@ void ctrl_io_write_word(unsigned int address, unsigned int data)
s68k_pulse_halt();
}
/* check if SUB-CPU status has changed */
if (s68k.cpu_stopped != status)
{
unsigned int base = scd.cartridge.boot;
/* PRG-RAM can only be accessed from MAIN 68K & Z80 when SUB-CPU is halted (Dungeon Explorer USA version) */
if (s68k.cpu_stopped & STOP_LEVEL_HALT)
{
/* PRG-RAM (128KB bank) is mapped to $020000-$03FFFF (resp. $420000-$43FFFF) */
m68k.memory_map[base + 0x02].read8 = m68k.memory_map[base + 0x03].read8 = NULL;
m68k.memory_map[base + 0x02].read16 = m68k.memory_map[base + 0x03].read16 = NULL;
m68k.memory_map[base + 0x02].write8 = m68k.memory_map[base + 0x03].write8 = NULL;
m68k.memory_map[base + 0x02].write16 = m68k.memory_map[base + 0x03].write16 = NULL;
zbank_memory_map[base + 0x02].read = zbank_memory_map[base + 0x03].read = NULL;
zbank_memory_map[base + 0x02].write = zbank_memory_map[base + 0x03].write = NULL;
}
else
{
/* $020000-$03FFFF (resp. $420000-$43FFFF) is not mapped */
m68k.memory_map[base + 0x02].read8 = m68k.memory_map[base + 0x03].read8 = m68k_read_bus_8;
m68k.memory_map[base + 0x02].read16 = m68k.memory_map[base + 0x03].read16 = m68k_read_bus_16;
m68k.memory_map[base + 0x02].write8 = m68k.memory_map[base + 0x03].write8 = m68k_unused_w_8;
m68k.memory_map[base + 0x02].write16 = m68k.memory_map[base + 0x03].write16 = m68k_unused_w_16;
zbank_memory_map[base + 0x02].read = zbank_memory_map[base + 0x03].read = zbank_unused_r;
zbank_memory_map[base + 0x02].write = zbank_memory_map[base + 0x03].write = zbank_unused_w;
}
}
/* IFL2 bit */
if (data & 0x100)
{

2
core/mem68k.h
View File

@ -3,7 +3,7 @@
* Main 68k bus handlers
*
* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003 Charles Mac Donald (original code)
* Copyright (C) 2007-2013 Eke-Eke (Genesis Plus GX)
* Copyright (C) 2007-2015 Eke-Eke (Genesis Plus GX)
*
* Redistribution and use of this code or any derivative works are permitted
* provided that the following conditions are met: