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-rw-r--r--src/devices/bus/bbc/internal/memex.h50
1 files changed, 50 insertions, 0 deletions
diff --git a/src/devices/bus/bbc/internal/memex.h b/src/devices/bus/bbc/internal/memex.h
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+++ b/src/devices/bus/bbc/internal/memex.h
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+// license:BSD-3-Clause
+// copyright-holders:Nigel Barnes
+/**********************************************************************
+
+ Memex B20 20K RAM expansion
+
+**********************************************************************/
+
+
+#ifndef MAME_BUS_BBC_INTERNAL_MEMEX_H
+#define MAME_BUS_BBC_INTERNAL_MEMEX_H
+
+#include "internal.h"
+
+
+//**************************************************************************
+// TYPE DEFINITIONS
+//**************************************************************************
+
+class bbc_memexb20_device : public device_t, public device_bbc_internal_interface
+{
+public:
+ // construction/destruction
+ bbc_memexb20_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
+
+protected:
+ // device-level overrides
+ virtual void device_start() override;
+
+ // optional information overrides
+ virtual const tiny_rom_entry *device_rom_region() const override;
+
+ virtual bool overrides_ram() override { return true; }
+ virtual uint8_t ram_r(offs_t offset) override;
+ virtual void ram_w(offs_t offset, uint8_t data) override;
+
+private:
+ void enable_w(uint8_t data);
+ void disable_w(uint8_t data);
+
+ bool m_shadow;
+ std::unique_ptr<uint8_t[]> m_ram;
+};
+
+
+// device type definition
+DECLARE_DEVICE_TYPE(BBC_MEMEXB20, bbc_memexb20_device);
+
+
+#endif /* MAME_BUS_BBC_INTERNAL_MEMEX_H */