diff options
Diffstat (limited to 'src/devices/bus/msx_cart/holy_quran.cpp')
-rw-r--r-- | src/devices/bus/msx_cart/holy_quran.cpp | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/src/devices/bus/msx_cart/holy_quran.cpp b/src/devices/bus/msx_cart/holy_quran.cpp new file mode 100644 index 00000000000..cb9d0b850a7 --- /dev/null +++ b/src/devices/bus/msx_cart/holy_quran.cpp @@ -0,0 +1,119 @@ +// license:BSD-3-Clause +// copyright-holders:Wilbert Pol +#include "emu.h" +#include "holy_quran.h" + + +const device_type MSX_CART_HOLY_QURAN = &device_creator<msx_cart_holy_quran>; + + +msx_cart_holy_quran::msx_cart_holy_quran(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) + : device_t(mconfig, MSX_CART_HOLY_QURAN, "MSX Cartridge - Holy Quran", tag, owner, clock, "msx_cart_holy_quran", __FILE__) + , msx_cart_interface(mconfig, *this) + , m_decrypt(false) +{ + for (int i = 0; i < 4; i++) + { + m_selected_bank[i] = 0; + m_bank_base[i] = NULL; + } + + /* protection uses a simple rotation on databus, some lines inverted: + D0 D4 D4 D5 + D1 ~ D3 D5 ~ D2 + D2 ~ D6 D6 D7 + D3 ~ D0 D7 D1 */ + for (int i=0; i < 0x100; i++) + { + m_lookup_prot[i] = (((i << 4) & 0x50) | ((i >> 3) & 5) | ((i << 1) & 0xa0) | ((i << 2) & 8) | ((i >> 6) & 2)) ^ 0x4d; + } +} + + +void msx_cart_holy_quran::device_start() +{ + save_item(NAME(m_selected_bank)); + save_item(NAME(m_decrypt)); + + machine().save().register_postload(save_prepost_delegate(FUNC(msx_cart_holy_quran::restore_banks), this)); +} + + +void msx_cart_holy_quran::restore_banks() +{ + m_bank_base[0] = get_rom_base() + (m_selected_bank[0] & 0x7f) * 0x2000; + m_bank_base[1] = get_rom_base() + (m_selected_bank[1] & 0x7f) * 0x2000; + m_bank_base[2] = get_rom_base() + (m_selected_bank[2] & 0x7f) * 0x2000; + m_bank_base[3] = get_rom_base() + (m_selected_bank[3] & 0x7f) * 0x2000; +} + + +void msx_cart_holy_quran::device_reset() +{ + for (int i = 0; i < 4; i++) + { + m_selected_bank[i] = 0; + } +} + + +void msx_cart_holy_quran::initialize_cartridge() +{ + if (get_rom_size() != 0x100000) + { + fatalerror("holy_quran: Invalid ROM size\n"); + } + + restore_banks(); +} + + +READ8_MEMBER(msx_cart_holy_quran::read_cart) +{ + if (offset >= 0x4000 && offset < 0xc000) + { + UINT8 data = m_bank_base[(offset - 0x4000) >> 13][offset & 0x1fff]; + + if (m_decrypt) + { + return m_lookup_prot[data]; + } + + // The decryption should actually start working after the first M1 cycle executing something + // from the cartridge. + if (offset == ((m_rom[3] << 8) | m_rom[2]) && !space.debugger_access()) + { + m_decrypt = true; + } + + return data; + } + return 0xff; +} + + +WRITE8_MEMBER(msx_cart_holy_quran::write_cart) +{ + switch (offset) + { + case 0x5000: + m_selected_bank[0] = data; + restore_banks(); + break; + case 0x5400: + m_selected_bank[1] = data; + restore_banks(); + break; + case 0x5800: + m_selected_bank[2] = data; + restore_banks(); + break; + case 0x5c00: + m_selected_bank[3] = data; + restore_banks(); + break; + default: + logerror("msx_cart_holy_quran: unhandled write %02x to %04x\n", data, offset); + break; + } +} |