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
|
// license:BSD-3-Clause
// copyright-holders:Angelo Salese
/**************************************************************************************************
Titan Overdrive 2 mapper
https://plutiedev.com/beyond-4mb
TODO:
- This is same as SSF2 mapper, merge at cart slot rewrite;
**************************************************************************************************/
#include "emu.h"
#include "titan.h"
DEFINE_DEVICE_TYPE(MD_ROM_TITAN, md_rom_titan_device, "md_rom_titan", "MD Titan Overdrive 2")
md_rom_titan_device::md_rom_titan_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: device_t(mconfig, MD_ROM_TITAN, tag, owner, clock)
, device_md_cart_interface(mconfig, *this)
{
}
void md_rom_titan_device::device_start()
{
for (int i = 0; i < 8; i++)
m_bank[i] = i;
save_pointer(NAME(m_bank), 8);
}
uint16_t md_rom_titan_device::read(offs_t offset)
{
if (offset < 0x400000/2)
{
const u32 bank_offset = offset >> (2 + 16);
const u32 bank_mask = 0x3ffff;
const u32 bank_mult = 0x40000;
//if (bank_offset != 0)
// printf("%08x %d %08x\n", offset * 2, bank_offset, m_rom_size);
return m_rom[((offset & bank_mask) | (m_bank[bank_offset] * bank_mult)) & (m_rom_size - 1)];
}
return 0xffff;
}
void md_rom_titan_device::write(offs_t offset, uint16_t data, uint16_t mem_mask)
{
}
void md_rom_titan_device::write_a13(offs_t offset, uint16_t data)
{
if (offset >= 0xf0/2)
{
offset -= 0xf0/2;
// bank 0 is fixed at 0-0x7ffff
if (offset)
{
//printf("%02x %02x\n", offset, data);
// D7-D6 unconnected, sgdk_bap (and likely others) cares about D4
m_bank[offset] = data & 0x3f;
}
}
}
|