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
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
|
// license:BSD-3-Clause
// copyright-holders:Nigel Barnes
/**********************************************************************
Watford Electronics 32K RAM card
http://chrisacorns.computinghistory.org.uk/8bit_Upgrades/WE_32KRAMcard.html
**********************************************************************/
#include "emu.h"
#include "we32kram.h"
//**************************************************************************
// DEVICE DEFINITIONS
//**************************************************************************
DEFINE_DEVICE_TYPE(BBC_WE32KRAM, bbc_we32kram_device, "bbc_we32kram", "Watford Electronics 32K Shadow RAM");
//-------------------------------------------------
// ROM( we32kram )
//-------------------------------------------------
ROM_START(we32kram)
ROM_REGION(0x4000, "exp_rom", 0)
ROM_SYSTEM_BIOS(0, "240", "v2.40")
ROMX_LOAD("we32kram_v2.40.rom", 0x0000, 0x2000, CRC(db9c3a1a) SHA1(0a5efb084eb1ae353b9c79c026e9e26cd7695293), ROM_BIOS(0))
ROM_SYSTEM_BIOS(1, "220", "v2.20")
ROMX_LOAD("we32kram_v2.20.rom", 0x0000, 0x2000, CRC(bc7124e0) SHA1(7f8536576de449916cd77488e94775ed438c5c6c), ROM_BIOS(1))
ROM_SYSTEM_BIOS(2, "200", "v2.00")
ROMX_LOAD("we32kram_v2.00.rom", 0x0000, 0x2000, CRC(1eff9b23) SHA1(98a3084b20c92427c2e9def58ade96f42659e20a), ROM_BIOS(2))
ROM_SYSTEM_BIOS(3, "106", "v1.06")
ROMX_LOAD("we32kram_v1.06.rom", 0x0000, 0x2000, CRC(b9749390) SHA1(210f6162d634fca8d75197d4f64d9b50abc01e1e), ROM_BIOS(3))
ROM_SYSTEM_BIOS(4, "100", "v1.00")
ROMX_LOAD("we32kram_v1.00.rom", 0x0000, 0x2000, CRC(7962b5db) SHA1(1b59a3354cfc704ad8aa60b0ed16e4cd2d815031), ROM_BIOS(4))
ROM_END
//-------------------------------------------------
// rom_region - device-specific ROM region
//-------------------------------------------------
const tiny_rom_entry *bbc_we32kram_device::device_rom_region() const
{
return ROM_NAME(we32kram);
}
//**************************************************************************
// LIVE DEVICE
//**************************************************************************
//-------------------------------------------------
// bbc_we32kram_device - constructor
//-------------------------------------------------
bbc_we32kram_device::bbc_we32kram_device(const machine_config &mconfig, const char *tag, device_t *owner, const XTAL &clock)
: device_t(mconfig, BBC_WE32KRAM, tag, owner, clock)
, device_bbc_internal_interface(mconfig, *this)
{
}
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void bbc_we32kram_device::device_start()
{
m_shadow = 2;
m_ram = std::make_unique<uint8_t[]>(0x8000);
/* register for save states */
save_item(NAME(m_shadow));
save_pointer(NAME(m_ram), 0x8000);
}
//-------------------------------------------------
// device_reset - device-specific reset
//-------------------------------------------------
void bbc_we32kram_device::device_reset()
{
address_space &program = m_maincpu->space(AS_PROGRAM);
program.install_write_handler(0xfffc, 0xffff, write8sm_delegate(*this, FUNC(bbc_we32kram_device::control_w)));
}
//**************************************************************************
// IMPLEMENTATION
//**************************************************************************
void bbc_we32kram_device::control_w(offs_t offset, uint8_t data)
{
m_shadow = offset;
}
uint8_t bbc_we32kram_device::ram_r(offs_t offset)
{
uint8_t data = 0xff;
switch (m_shadow)
{
case 0:
/* &fffc - swap whole memory */
data = m_ram[offset];
break;
case 2:
/* &fffe - select BBC ram */
data = m_mb_ram->pointer()[offset];
break;
case 3:
/* &ffff - select Watford ram */
if (offset >= 0x3000)
data = m_ram[offset];
else
data = m_mb_ram->pointer()[offset];
break;
}
return data;
}
void bbc_we32kram_device::ram_w(offs_t offset, uint8_t data)
{
switch (m_shadow)
{
case 0:
/* &fffc - swap whole memory */
m_ram[offset] = data;
break;
case 2:
/* &fffe - select BBC ram */
m_mb_ram->pointer()[offset] = data;
break;
case 3:
/* &ffff - select Watford ram */
if (offset >= 0x3000)
m_ram[offset] = data;
else
m_mb_ram->pointer()[offset] = data;
break;
}
}
|