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-rw-r--r--src/devices/bus/ti99/internal/buffram.h49
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diff --git a/src/devices/bus/ti99/internal/buffram.h b/src/devices/bus/ti99/internal/buffram.h
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+// license:LGPL-2.1+
+// copyright-holders:Michael Zapf
+/*******************************************************************************
+
+ Buffered RAM circuit.
+
+ Michael Zapf
+ March 2020
+
+*******************************************************************************/
+
+#ifndef MAME_BUS_TI99_INTERNAL_BRAM_H
+#define MAME_BUS_TI99_INTERNAL_BRAM_H
+
+#pragma once
+
+namespace bus::ti99::internal {
+
+// =========== Buffered RAM ================
+class buffered_ram_device : public device_t, public device_nvram_interface
+{
+public:
+ buffered_ram_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
+ buffered_ram_device &set_size(int size) { m_size = size; return *this; }
+
+ // read/write
+ uint8_t read(offs_t offset) { return m_mem[offset % m_size]; }
+ void write(offs_t offset, uint8_t data) { m_mem[offset % m_size] = data; }
+
+ void set_buffered(bool on) { nvram_enable_backup(on); }
+
+private:
+ virtual void device_start() override;
+
+ // derived class overrides
+ virtual void nvram_default() override;
+ virtual bool nvram_read(util::read_stream &file) override;
+ virtual bool nvram_write(util::write_stream &file) override;
+
+ int m_size;
+ std::unique_ptr<u8 []> m_mem;
+};
+
+
+} // end namespace bus::ti99::internal
+
+DECLARE_DEVICE_TYPE_NS(BUFF_RAM, bus::ti99::internal, buffered_ram_device)
+
+#endif // MAME_BUS_TI99_INTERNAL_BRAM_H