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-rw-r--r--src/devices/bus/vic20/megacart.c130
1 files changed, 130 insertions, 0 deletions
diff --git a/src/devices/bus/vic20/megacart.c b/src/devices/bus/vic20/megacart.c
new file mode 100644
index 00000000000..e92e1dbbc55
--- /dev/null
+++ b/src/devices/bus/vic20/megacart.c
@@ -0,0 +1,130 @@
+// license:BSD-3-Clause
+// copyright-holders:Curt Coder
+/**********************************************************************
+
+ Mega-Cart cartridge emulation
+
+**********************************************************************/
+
+#include "megacart.h"
+
+
+
+//**************************************************************************
+// DEVICE DEFINITIONS
+//**************************************************************************
+
+const device_type VIC20_MEGACART = &device_creator<vic20_megacart_device>;
+
+
+//-------------------------------------------------
+// MACHINE_DRIVER( vic20_megacart )
+//-------------------------------------------------
+
+static MACHINE_CONFIG_FRAGMENT( vic20_megacart )
+
+MACHINE_CONFIG_END
+
+
+//-------------------------------------------------
+// machine_config_additions - device-specific
+// machine configurations
+//-------------------------------------------------
+
+machine_config_constructor vic20_megacart_device::device_mconfig_additions() const
+{
+ return MACHINE_CONFIG_NAME( vic20_megacart );
+}
+
+
+
+//**************************************************************************
+// LIVE DEVICE
+//**************************************************************************
+
+//-------------------------------------------------
+// vic20_megacart_device - constructor
+//-------------------------------------------------
+
+vic20_megacart_device::vic20_megacart_device(const machine_config &mconfig, const char *tag, device_t *owner, UINT32 clock)
+ : device_t(mconfig, VIC20_MEGACART, "Mega-Cart", tag, owner, clock, "megacart", __FILE__),
+ device_vic20_expansion_card_interface(mconfig, *this),
+ device_nvram_interface(mconfig, *this),
+ m_nvram_en(0)
+{
+}
+
+
+//-------------------------------------------------
+// device_start - device-specific startup
+//-------------------------------------------------
+
+void vic20_megacart_device::device_start()
+{
+ m_nvram.allocate(0x2000);
+
+ // state saving
+ save_item(NAME(m_nvram_en));
+}
+
+
+//-------------------------------------------------
+// device_reset - device-specific reset
+//-------------------------------------------------
+
+void vic20_megacart_device::device_reset()
+{
+}
+
+
+//-------------------------------------------------
+// vic20_cd_r - cartridge data read
+//-------------------------------------------------
+
+UINT8 vic20_megacart_device::vic20_cd_r(address_space &space, offs_t offset, UINT8 data, int ram1, int ram2, int ram3, int blk1, int blk2, int blk3, int blk5, int io2, int io3)
+{
+ if (!ram1 || !ram2 || !ram3 || !io2 || !io3)
+ {
+ if (m_nvram_en)
+ {
+ data = m_nvram[offset & 0x1fff];
+ }
+ }
+ else if (!blk1 || !blk2 || !blk3)
+ {
+ }
+ else if (!blk5)
+ {
+ }
+
+ return data;
+}
+
+
+//-------------------------------------------------
+// vic20_cd_w - cartridge data write
+//-------------------------------------------------
+
+void vic20_megacart_device::vic20_cd_w(address_space &space, offs_t offset, UINT8 data, int ram1, int ram2, int ram3, int blk1, int blk2, int blk3, int blk5, int io2, int io3)
+{
+ if (!ram1 || !ram2 || !ram3 || !io2)
+ {
+ if (m_nvram_en)
+ {
+ m_nvram[offset & 0x1fff] = data;
+ }
+ }
+ else if (!blk1 || !blk2 || !blk3)
+ {
+ }
+ else if (!blk5)
+ {
+ }
+ else if (!io3)
+ {
+ if (m_nvram_en)
+ {
+ m_nvram[offset & 0x1fff] = data;
+ }
+ }
+}