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Diffstat (limited to 'src/devices/bus/bbc/rom/dfs.cpp')
-rw-r--r--src/devices/bus/bbc/rom/dfs.cpp63
1 files changed, 63 insertions, 0 deletions
diff --git a/src/devices/bus/bbc/rom/dfs.cpp b/src/devices/bus/bbc/rom/dfs.cpp
new file mode 100644
index 00000000000..8a3aac6d588
--- /dev/null
+++ b/src/devices/bus/bbc/rom/dfs.cpp
@@ -0,0 +1,63 @@
+// license:BSD-3-Clause
+// copyright-holders:Nigel Barnes
+/***************************************************************************
+
+ BBC Micro MRM E00 DFS emulation
+
+ Comprises of 8K ROM and 2K/4K? RAM on a carrier board, with flying lead
+ to RW line to enable writing to RAM.
+
+***************************************************************************/
+
+#include "emu.h"
+#include "dfs.h"
+
+
+//**************************************************************************
+// DEVICE DEFINITIONS
+//**************************************************************************
+
+DEFINE_DEVICE_TYPE(BBC_MRME00, bbc_mrme00_device, "bbc_mrme00", "BBC Micro MRM E00 DFS")
+
+//**************************************************************************
+// LIVE DEVICE
+//**************************************************************************
+
+//-------------------------------------------------
+// bbc_rom_device - constructor
+//-------------------------------------------------
+
+bbc_mrme00_device::bbc_mrme00_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock)
+ : device_t(mconfig, BBC_MRME00, tag, owner, clock)
+ , device_bbc_rom_interface(mconfig, *this)
+{
+}
+
+//-------------------------------------------------
+// device_start - device-specific startup
+//-------------------------------------------------
+
+void bbc_mrme00_device::device_start()
+{
+}
+
+//-------------------------------------------------
+// read
+//-------------------------------------------------
+
+uint8_t bbc_mrme00_device::read(offs_t offset)
+{
+ if (offset < get_rom_size())
+ return get_rom_base()[offset & (get_rom_size() - 1)];
+ else
+ return get_ram_base()[offset & (get_ram_size() - 1)];
+}
+
+//-------------------------------------------------
+// write
+//-------------------------------------------------
+
+void bbc_mrme00_device::write(offs_t offset, uint8_t data)
+{
+ get_ram_base()[offset & (get_ram_size() - 1)] = data;
+}