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Diffstat (limited to 'src/devices/bus/bbc/internal/memex.h')
-rw-r--r-- | src/devices/bus/bbc/internal/memex.h | 50 |
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 new file mode 100644 index 00000000000..1e4f07bcb16 --- /dev/null +++ b/src/devices/bus/bbc/internal/memex.h @@ -0,0 +1,50 @@ +// 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 */ |