1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
|
// 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"
namespace {
//-------------------------------------------------
// initialization
//-------------------------------------------------
class o2_ktaa_device : public device_t, public device_o2_cart_interface
{
public:
o2_ktaa_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock);
protected:
virtual void device_start() override ATTR_COLD;
virtual void cart_init() override;
virtual u8 read_rom04(offs_t offset) override;
virtual u8 read_rom0c(offs_t offset) override { return read_rom04(offset + 0x800); }
virtual void write_p1(u8 data) override { m_bank = data & m_bank_mask; }
private:
u32 m_page_size = 0;
u8 m_bank_mask = 0;
u8 m_bank = 0;
};
o2_ktaa_device::o2_ktaa_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 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];
}
} // anonymous namespace
DEFINE_DEVICE_TYPE_PRIVATE(O2_ROM_KTAA, device_o2_cart_interface, o2_ktaa_device, "o2_ktaa", "Videopac+ KTAA Cartridge")
|