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// 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_t 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] = nullptr;
}
/* 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 (auto & elem : m_selected_bank)
{
elem = 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_t 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]) && !machine().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;
}
}
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