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
|
// license:BSD-3-Clause
// copyright-holders:Fabio Priuli
/***********************************************************************************************************
A800 SpartaDOS cart emulation
***********************************************************************************************************/
#include "emu.h"
#include "sparta.h"
//-------------------------------------------------
// constructor
//-------------------------------------------------
DEFINE_DEVICE_TYPE(A800_ROM_SPARTADOS, a800_rom_spartados_device, "a800_sparta", "Atari 800 SpartaDOS ROM Carts")
a800_rom_spartados_device::a800_rom_spartados_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: a800_rom_device(mconfig, A800_ROM_SPARTADOS, tag, owner, clock)
, m_bank(0)
, m_subslot_enabled(0)
{
}
void a800_rom_spartados_device::device_start()
{
save_item(NAME(m_bank));
save_item(NAME(m_subslot_enabled));
}
void a800_rom_spartados_device::device_reset()
{
m_bank = 0;
m_subslot_enabled = 0;
}
/*-------------------------------------------------
mapper specific handlers
-------------------------------------------------*/
/*-------------------------------------------------
SpartaDOS 64K carts
Similar to Express / Diamond carts, because
bankswitch is controlled by writing to 7 diff
offsets in reverse order, but writes to offsets
0x8-0xf also enable/disable subslot
-------------------------------------------------*/
uint8_t a800_rom_spartados_device::read_80xx(offs_t offset)
{
if (!m_subslot_enabled)
return m_rom[(offset & 0x1fff) + (m_bank * 0x2000)];
else
return 0xff; // subslot, currently not implemented
}
void a800_rom_spartados_device::write_d5xx(offs_t offset, uint8_t data)
{
if (offset & 0x08)
m_subslot_enabled = !BIT(offset, 2);
else
m_bank = (offset ^ 0x07) & 0x0f;
}
|