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
89
|
// license:BSD-3-Clause
// copyright-holders:Fabio Priuli
/***********************************************************************************************************
GCE Vectrex cart emulation
TODO:
- better understand how much SRAM is expected to be present by the homebrew using
this cart type and use a RAM array instead of the ROM region for writes
***********************************************************************************************************/
#include "emu.h"
#include "rom.h"
//-------------------------------------------------
// vectrex_rom_device - constructor
//-------------------------------------------------
DEFINE_DEVICE_TYPE(VECTREX_ROM_STD, vectrex_rom_device, "vectrex_rom", "Vectrex Standard Carts")
DEFINE_DEVICE_TYPE(VECTREX_ROM_64K, vectrex_rom64k_device, "vectrex_64k", "Vectrex Carts w/Bankswitch")
DEFINE_DEVICE_TYPE(VECTREX_ROM_SRAM, vectrex_sram_device, "vectrex_sram", "Vectrex Carts w/SRAM")
vectrex_rom_device::vectrex_rom_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, uint32_t clock)
: device_t(mconfig, type, tag, owner, clock), device_vectrex_cart_interface(mconfig, *this)
{
}
vectrex_rom_device::vectrex_rom_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: vectrex_rom_device(mconfig, VECTREX_ROM_STD, tag, owner, clock)
{
}
vectrex_rom64k_device::vectrex_rom64k_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: vectrex_rom_device(mconfig, VECTREX_ROM_64K, tag, owner, clock), m_bank(0)
{
}
vectrex_sram_device::vectrex_sram_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
: vectrex_rom_device(mconfig, VECTREX_ROM_SRAM, tag, owner, clock)
{
}
void vectrex_rom64k_device::device_start()
{
save_item(NAME(m_bank));
}
void vectrex_rom64k_device::device_reset()
{
// Resetting to 1 instead of 0 fixes 64KiB cartridges that don't have a workaround
// for the fact that MAME does not currently emulate the pull-up resistor on the 6522's PB6 line.
// TODO: correctly emulate PB6 pull-up behavior (line should be high whenever PB6 set to input).
m_bank = 1;
}
/*-------------------------------------------------
mapper specific handlers
-------------------------------------------------*/
READ8_MEMBER(vectrex_rom_device::read_rom)
{
if (offset < m_rom_size)
return m_rom[offset];
else
return 0xff;
}
READ8_MEMBER(vectrex_rom64k_device::read_rom)
{
return m_rom[(offset + m_bank * 0x8000) & (m_rom_size - 1)];
}
WRITE8_MEMBER(vectrex_rom64k_device::write_bank)
{
m_bank = data >> 6;
}
WRITE8_MEMBER(vectrex_sram_device::write_ram)
{
m_rom[offset & (m_rom_size - 1)] = data;
}
|