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// license:BSD-3-Clause
// copyright-holders:Wilbert Pol, Fabio Priuli, hap
/******************************************************************************
Homebrew KTAA(Kill the Attacking Aliens) cartridge emulation
Bankswitched ROM with page size of 3KB.
******************************************************************************/
#include "emu.h"
#include "ktaa.h"
DEFINE_DEVICE_TYPE(O2_ROM_KTAA, o2_ktaa_device, "o2_ktaa", "Videopac+ KTAA Cartridge")
//-------------------------------------------------
// o2_ktaa_device - constructor
//-------------------------------------------------
o2_ktaa_device::o2_ktaa_device(const machine_config &mconfig, const char *tag, device_t *owner, const XTAL &clock) :
device_t(mconfig, O2_ROM_KTAA, tag, owner, clock),
device_o2_cart_interface(mconfig, *this)
{ }
void o2_ktaa_device::device_start()
{
save_item(NAME(m_bank));
}
void o2_ktaa_device::cart_init()
{
bool err = false;
if (m_rom_size & (m_rom_size - 1))
{
// freely released binary file is 12KB
err = m_rom_size != 0xc00 && m_rom_size != 0xc00*2 && m_rom_size != 0xc00*4;
m_page_size = 0xc00;
}
else
{
// actual ROM is 16KB(27C128), first 1KB of each 4KB block is empty
err = m_rom_size < 0x1000;
m_page_size = 0x1000;
}
if (err)
fatalerror("o2_ktaa_device: ROM size must be multiple of 3KB or 4KB\n");
m_bank_mask = (m_rom_size / m_page_size) - 1;
}
//-------------------------------------------------
// mapper specific handlers
//-------------------------------------------------
u8 o2_ktaa_device::read_rom04(offs_t offset)
{
offset += m_page_size - 0xc00;
return m_rom[offset + m_bank * m_page_size];
}
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