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/**********************************************************************
Brown Boxes Double Quick Brown Box emulation
Copyright MESS Team.
Visit http://mamedev.org for licensing and usage restrictions.
**********************************************************************/
/*
TODO:
- 64/128 mode switch
- dump of the initial NVRAM contents
*/
#include "dqbb.h"
//**************************************************************************
// DEVICE DEFINITIONS
//**************************************************************************
const device_type C64_DQBB = &device_creator<c64_dqbb_cartridge_device>;
//**************************************************************************
// LIVE DEVICE
//**************************************************************************
//-------------------------------------------------
// c64_dqbb_cartridge_device - constructor
//-------------------------------------------------
c64_dqbb_cartridge_device::c64_dqbb_cartridge_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock) :
device_t(mconfig, C64_DQBB, "C64 Double Quick Brown Box cartridge", tag, owner, clock, "c64_dqbb", __FILE__),
device_c64_expansion_card_interface(mconfig, *this),
device_nvram_interface(mconfig, *this)
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void c64_dqbb_cartridge_device::device_start()
{
// allocate memory
c64_nvram_pointer(machine(), 0x4000);
// state saving
save_item(NAME(m_cs));
save_item(NAME(m_we));
}
//-------------------------------------------------
// device_reset - device-specific reset
//-------------------------------------------------
void c64_dqbb_cartridge_device::device_reset()
{
m_exrom = 0; // TODO 1 in 128 mode
m_game = 1;
m_cs = 0;
m_we = 0;
}
//-------------------------------------------------
// c64_cd_r - cartridge data read
//-------------------------------------------------
UINT8 c64_dqbb_cartridge_device::c64_cd_r(address_space &space, offs_t offset, UINT8 data, int sphi2, int ba, int roml, int romh, int io1, int io2)
{
if (!m_cs && (!roml || !romh))
{
data = m_nvram[offset & 0x3fff];
}
return data;
}
//-------------------------------------------------
// c64_cd_w - cartridge data write
//-------------------------------------------------
void c64_dqbb_cartridge_device::c64_cd_w(address_space &space, offs_t offset, UINT8 data, int sphi2, int ba, int roml, int romh, int io1, int io2)
{
if (!m_cs && m_we && (offset >= 0x8000 && offset < 0xc000))
{
m_nvram[offset & 0x3fff] = data;
}
else if (!io1)
{
/*
bit description
0
1
2 GAME
3
4 WE
5
6 EXROM
7 _CS
*/
m_exrom = !BIT(data, 6);
m_game = !BIT(data, 2);
m_we = BIT(data, 4);
m_cs = BIT(data, 7);
}
}
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