1 // license:BSD-3-Clause
2 // copyright-holders:Curt Coder
3 /**********************************************************************
4 
5     Berkeley Softworks GeoRAM emulation
6 
7 **********************************************************************/
8 
9 #include "emu.h"
10 #include "georam.h"
11 
12 
13 
14 //**************************************************************************
15 //  DEVICE DEFINITIONS
16 //**************************************************************************
17 
18 DEFINE_DEVICE_TYPE(C64_GEORAM, c64_georam_cartridge_device, "c64_georam", "C64 GeoRAM cartridge")
19 
20 
21 
22 //**************************************************************************
23 //  LIVE DEVICE
24 //**************************************************************************
25 
26 //-------------------------------------------------
27 //  c64_georam_cartridge_device - constructor
28 //-------------------------------------------------
29 
c64_georam_cartridge_device(const machine_config & mconfig,const char * tag,device_t * owner,uint32_t clock)30 c64_georam_cartridge_device::c64_georam_cartridge_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) :
31 	device_t(mconfig, C64_GEORAM, tag, owner, clock),
32 	device_c64_expansion_card_interface(mconfig, *this),
33 	m_ram(*this, "ram"),
34 	m_bank(0)
35 {
36 }
37 
38 
39 //-------------------------------------------------
40 //  device_start - device-specific startup
41 //-------------------------------------------------
42 
device_start()43 void c64_georam_cartridge_device::device_start()
44 {
45 	// allocate memory
46 	m_ram.allocate(0x80000);
47 
48 	// state saving
49 	save_item(NAME(m_bank));
50 }
51 
52 
53 //-------------------------------------------------
54 //  device_reset - device-specific reset
55 //-------------------------------------------------
56 
device_reset()57 void c64_georam_cartridge_device::device_reset()
58 {
59 	m_bank = 0;
60 }
61 
62 
63 //-------------------------------------------------
64 //  c64_cd_r - cartridge data read
65 //-------------------------------------------------
66 
c64_cd_r(offs_t offset,uint8_t data,int sphi2,int ba,int roml,int romh,int io1,int io2)67 uint8_t c64_georam_cartridge_device::c64_cd_r(offs_t offset, uint8_t data, int sphi2, int ba, int roml, int romh, int io1, int io2)
68 {
69 	if (!io1)
70 	{
71 		offs_t addr = (m_bank << 8) | (offset & 0xff);
72 		data = m_ram[addr];
73 	}
74 
75 	return data;
76 }
77 
78 
79 //-------------------------------------------------
80 //  c64_cd_w - cartridge data write
81 //-------------------------------------------------
82 
c64_cd_w(offs_t offset,uint8_t data,int sphi2,int ba,int roml,int romh,int io1,int io2)83 void c64_georam_cartridge_device::c64_cd_w(offs_t offset, uint8_t data, int sphi2, int ba, int roml, int romh, int io1, int io2)
84 {
85 	if (!io1)
86 	{
87 		offs_t addr = (m_bank << 8) | (offset & 0xff);
88 		m_ram[addr] = data;
89 	}
90 	else if (!io2)
91 	{
92 		if (BIT(offset, 0))
93 		{
94 			m_bank = ((data & 0x1f) << 6) | (m_bank & 0x3f);
95 		}
96 		else
97 		{
98 			m_bank = (m_bank & 0x7c0) | (data & 0x3f);
99 		}
100 	}
101 }
102