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◆ main openmsx / src / video / v9990 / V9990VRAM.hh
2.4 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
e8555c89 Andy McCall 1 
#ifndef V9990VRAM_HH
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#define V9990VRAM_HH
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#include "V9990CmdEngine.hh"
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#include "EmuTime.hh"
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#include "TrackedRam.hh"
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#include <cstdint>
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namespace openmsx {
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class V9990;
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/** Video RAM for the V9990.
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  */
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class V9990VRAM
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{
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public:
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	/** VRAM Size
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	  */
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	static constexpr unsigned VRAM_SIZE = 512 * 1024; // 512kB
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	/** Construct V9990 VRAM.
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	  * @param vdp The V9990 vdp this VRAM belongs to
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	  * @param time  Moment in time to create the VRAM
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	  */
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	V9990VRAM(V9990& vdp, EmuTime time);
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	void clear();
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	/** Update VRAM state to specified moment in time.
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	  * @param time Moment in emulated time to synchronize VRAM to
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	  */
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	void sync(EmuTime time) {
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		cmdEngine->sync(time);
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	}
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	[[nodiscard]] static unsigned transformBx(unsigned address) {
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		return ((address & 1) << 18) | ((address & 0x7FFFE) >> 1);
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	}
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	[[nodiscard]] static unsigned transformP1(unsigned address) {
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		return address;
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	}
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	[[nodiscard]] static unsigned transformP2(unsigned address) {
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		// Verified on a real Graphics9000
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		if (address < 0x78000) {
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			return transformBx(address);
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		} else if (address < 0x7C000) {
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			return address - 0x3C000;
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		} else {
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			return address;
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		}
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	}
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	[[nodiscard]] uint8_t readVRAMBx(unsigned address) const {
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		return data[transformBx(address)];
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	}
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	[[nodiscard]] uint8_t readVRAMP1(unsigned address) const {
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		return data[transformP1(address)];
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	}
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	[[nodiscard]] uint8_t readVRAMP2(unsigned address) const {
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		return data[transformP2(address)];
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	}
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	void writeVRAMBx(unsigned address, uint8_t value) {
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		data.write(transformBx(address), value);
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	}
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	void writeVRAMP1(unsigned address, uint8_t value) {
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		data.write(transformP1(address), value);
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	}
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	void writeVRAMP2(unsigned address, uint8_t value) {
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		data.write(transformP2(address), value);
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	}
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	[[nodiscard]] uint8_t readVRAMDirect(unsigned address) const {
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		return data[address];
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	}
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	void writeVRAMDirect(unsigned address, uint8_t value) {
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		data.write(address, value);
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	}
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	[[nodiscard]] uint8_t readVRAMCPU(unsigned address, EmuTime time);
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	void writeVRAMCPU(unsigned address, uint8_t val, EmuTime time);
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	void setCmdEngine(V9990CmdEngine& cmdEngine_) { cmdEngine = &cmdEngine_; }
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	template<typename Archive>
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	void serialize(Archive& ar, unsigned version);
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private:
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	[[nodiscard]] unsigned mapAddress(unsigned address) const;
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private:
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	/** V9990 VDP this VRAM belongs to.
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	  */
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	V9990& vdp;
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	V9990CmdEngine* cmdEngine = nullptr;
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	/** V9990 VRAM data.
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	  */
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	TrackedRam data;
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};
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} // namespace openmsx
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#endif