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// license:BSD-3-Clause
// copyright-holders:Wilbert Pol
/*
Emulation for the bunsetsu internal firmware mapper found in a number of MSX machines
*/
#include "emu.h"
#include "bunsetsu.h"
DEFINE_DEVICE_TYPE(MSX_SLOT_BUNSETSU, msx_slot_bunsetsu_device, "msx_slot_bunsetsu", "MSX Internal BUNSETSU")
msx_slot_bunsetsu_device::msx_slot_bunsetsu_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
: msx_slot_rom_device(mconfig, MSX_SLOT_BUNSETSU, tag, owner, clock)
, m_bunsetsu_region(*this, finder_base::DUMMY_TAG)
, m_bunsetsu_address(0)
{
}
void msx_slot_bunsetsu_device::device_start()
{
msx_slot_rom_device::device_start();
save_item(NAME(m_bunsetsu_address));
page(2)->install_read_handler(0xbfff, 0xbfff, emu::rw_delegate(*this, FUNC(msx_slot_bunsetsu_device::buns_read)));
page(2)->install_write_handler(0xbffc, 0xbffe, emu::rw_delegate(*this, FUNC(msx_slot_bunsetsu_device::buns_write)));
}
void msx_slot_bunsetsu_device::device_reset()
{
m_bunsetsu_address = 0;
}
u8 msx_slot_bunsetsu_device::buns_read()
{
u8 data = m_bunsetsu_region[m_bunsetsu_address & 0x1ffff];
if (!machine().side_effects_disabled())
m_bunsetsu_address++;
return data;
}
void msx_slot_bunsetsu_device::buns_write(offs_t offset, u8 data)
{
switch (offset)
{
case 0:
m_bunsetsu_address = (m_bunsetsu_address & 0xffff00) | data;
break;
case 1:
m_bunsetsu_address = (m_bunsetsu_address & 0xff00ff) | (data << 8);
break;
case 2:
m_bunsetsu_address = (m_bunsetsu_address & 0x00ffff) | (data << 16);
break;
}
}
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