// $Id: VDPCmdEngine.hh 5969 2006-12-29 14:53:25Z m9710797 $

#ifndef VDPCMDENGINE_HH
#define VDPCMDENGINE_HH

#include "VDP.hh"
#include "DisplayMode.hh"
#include "Observer.hh"
#include "openmsx.hh"
#include "noncopyable.hh"
#include "likely.hh"
#include <memory>

namespace openmsx {

class VDPVRAM;
class CommandController;
class RenderSettings;
class BooleanSetting;

/** VDP command engine by Alex Wulms.
  * Implements command execution unit of V9938/58.
  */
class VDPCmdEngine : private Observer<Setting>, private noncopyable
{
public:
	VDPCmdEngine(VDP& vdp, RenderSettings& renderSettings_,
	             CommandController& commandController);
	virtual ~VDPCmdEngine();

	/** Reinitialise Renderer state.
	  * @param time The moment in time the reset occurs.
	  */
	void reset(const EmuTime& time);

	/** Synchronises the command engine with the VDP.
	  * Ideally this would be a private method, but the current
	  * design doesn't allow that.
	  * @param time The moment in emulated time to sync to.
	  */
	inline void sync(const EmuTime& time) {
		if (currentCommand) currentCommand->execute(time);
	}

	/** Gets the command engine status (part of S#2).
	  * Bit 7 (TR) is set when the command engine is ready for
	  * a pixel transfer.
	  * Bit 4 (BD) is set when the boundary colour is detected.
	  * Bit 0 (CE) is set when a command is in progress.
	  */
	inline byte getStatus(const EmuTime& time) {
		if (time >= statusChangeTime) {
			sync(time);
		}
		return status;
	}

	/** Use this method to transfer pixel(s) from VDP to CPU.
	  * This method implements V9938 S#7.
	  * @param time The moment in emulated time this read occurs.
	  * @return Colour value of the pixel.
	  */
	inline byte readColour(const EmuTime& time) {
		sync(time);
		return COL;
	}
	inline void resetColour() {
		// Note: Real VDP always resets TR, but for such a short time
		//       that the MSX won't notice it.
		// TODO: What happens on non-transfer commands?
		if (!currentCommand) status &= 0x7F;
		transfer = true;
	}

	/** Gets the X coordinate of a border detected by SRCH (intended behaviour,
          * as documented in the V9938 technical data book). However, real VDP
          * simply returns the current value of the ASX 'temporary source X' counter,
          * regardless of the command that is being executed or was executed most
          * recently
	  * @param time The moment in emulated time this get occurs.
	  */
	inline unsigned getBorderX(const EmuTime& time) {
		sync(time);
		return ASX;
	}

	/** Writes to a command register.
	  * @param index The register [0..14] to write to.
	  * @param value The new value for the specified register.
	  * @param time The moment in emulated time this write occurs.
	  */
	void setCmdReg(byte index, byte value, const EmuTime& time);

	/** Read the content of a command register. This method is meant to
	  * be used by the debugger, there is no strict guarantee that the
	  * returned value is the correct value at _exactly_ this moment in
	  * time (IOW this method does not sync the complete CmdEngine)
	  * @param index The register [0..14] to read from.
	  */
	byte peekCmdReg(byte index);

	/** Informs the command engine of a VDP display mode change.
	  * @param mode The new display mode.
	  * @param time The moment in emulated time this change occurs.
	  */
	void updateDisplayMode(DisplayMode mode, const EmuTime& time);

	/** Interface for logical operations.
	  */
	class LogOp {
	public:
		/** Write a pixel using a logical operation.
		  * @param time Time at which the write occurs.
		  * @param vram Pointer to VRAM class.
		  * @param addr Address of pixel in VRAM.
		  * @param colour Colour of pixel to be written,
		  *   shifted if necessary to correspond to the right VRAM position.
		  * @param mask Read mask: bit positions that are 1 are read from
		  *   VRAM before the write is performed.
		  */
		virtual void pset(const EmuTime& time, VDPVRAM& vram,
		                  unsigned addr, byte colour, byte mask) = 0;
		virtual ~LogOp() {}
	};

private:
	/** Represents V9938 Graphic 4 mode (SCREEN5).
	  */
	class Graphic4Mode {
	public:
		static const byte COLOUR_MASK = 0x0F;
		static const byte PIXELS_PER_BYTE = 2;
		static const byte PIXELS_PER_BYTE_SHIFT = 1;
		static const unsigned PIXELS_PER_LINE = 256;
		static inline unsigned addressOf(unsigned x, unsigned y, bool extVRAM);
		static inline byte point(VDPVRAM& vram, unsigned x, unsigned y, bool extVRAM);
		static inline void pset(const EmuTime& time, VDPVRAM& vram,
			unsigned x, unsigned y, bool extVRAM, byte colour, LogOp& op);
	};

	/** Represents V9938 Graphic 5 mode (SCREEN6).
	  */
	class Graphic5Mode {
	public:
		static const byte COLOUR_MASK = 0x03;
		static const byte PIXELS_PER_BYTE = 4;
		static const byte PIXELS_PER_BYTE_SHIFT = 2;
		static const unsigned PIXELS_PER_LINE = 512;
		static inline unsigned addressOf(unsigned x, unsigned y, bool extVRAM);
		static inline byte point(VDPVRAM& vram, unsigned x, unsigned y, bool extVRAM);
		static inline void pset(const EmuTime& time, VDPVRAM& vram,
			unsigned x, unsigned y, bool extVRAM, byte colour, LogOp& op);
	};

	/** Represents V9938 Graphic 6 mode (SCREEN7).
	  */
	class Graphic6Mode {
	public:
		static const byte COLOUR_MASK = 0x0F;
		static const byte PIXELS_PER_BYTE = 2;
		static const byte PIXELS_PER_BYTE_SHIFT = 1;
		static const unsigned PIXELS_PER_LINE = 512;
		static inline unsigned addressOf(unsigned x, unsigned y, bool extVRAM);
		static inline byte point(VDPVRAM& vram, unsigned x, unsigned y, bool extVRAM);
		static inline void pset(const EmuTime& time, VDPVRAM& vram,
			unsigned x, unsigned y, bool extVRAM, byte colour, LogOp& op);
	};

	/** Represents V9938 Graphic 7 mode (SCREEN8).
	  */
	class Graphic7Mode {
	public:
		static const byte COLOUR_MASK = 0xFF;
		static const byte PIXELS_PER_BYTE = 1;
		static const byte PIXELS_PER_BYTE_SHIFT = 0;
		static const unsigned PIXELS_PER_LINE = 256;
		static inline unsigned addressOf(unsigned x, unsigned y, bool extVRAM);
		static inline byte point(VDPVRAM& vram, unsigned x, unsigned y, bool extVRAM);
		static inline void pset(const EmuTime& time, VDPVRAM& vram,
			unsigned x, unsigned y, bool extVRAM, byte colour, LogOp& op);
	};

	/** This is an abstract base class the VDP commands
	  */
	class VDPCmd {
	public:
		VDPCmd(VDPCmdEngine& engine, VDPVRAM& vram);
		virtual ~VDPCmd();

		/** Prepare execution of cmd
		  */
		virtual void start(const EmuTime& time) = 0;

		/** Perform a given V9938 graphical operation.
		  */
		virtual void execute(const EmuTime& time) = 0;

	protected:
		VDPCmdEngine& engine;
		VDPVRAM& vram;
	};

	template <template <class Mode> class Command>
	void createEngines(unsigned cmd);

	/** Abort
	  */
	class AbortCmd : public VDPCmd {
	public:
		AbortCmd(VDPCmdEngine& engine, VDPVRAM& vram);
		virtual void start(const EmuTime& time);
		virtual void execute(const EmuTime& time);
	};

	/** Point
	  */
	template <class Mode>
	class PointCmd : public VDPCmd {
	public:
		PointCmd(VDPCmdEngine& engine, VDPVRAM& vram);
		virtual void start(const EmuTime& time);
		virtual void execute(const EmuTime& time);
	};

	/** Pset
	  */
	template <class Mode>
	class PsetCmd : public VDPCmd {
	public:
		PsetCmd(VDPCmdEngine& engine, VDPVRAM& vram);
		virtual void start(const EmuTime& time);
		virtual void execute(const EmuTime& time);
	};

	/** Search a dot.
	  */
	template <class Mode>
	class SrchCmd : public VDPCmd {
	public:
		SrchCmd(VDPCmdEngine& engine, VDPVRAM& vram);
		virtual void start(const EmuTime& time);
		virtual void execute(const EmuTime& time);
	};

	/** Draw a line.
	  */
	template <class Mode>
	class LineCmd : public VDPCmd {
	public:
		LineCmd(VDPCmdEngine& engine, VDPVRAM& vram);
		virtual void start(const EmuTime& time);
		virtual void execute(const EmuTime& time);
	};

	/** Abstract base class for block commands.
	  */
	class BlockCmd : public VDPCmd {
	public:
		BlockCmd(VDPCmdEngine& engine, VDPVRAM& vram, const unsigned* timing);
	protected:
		void calcFinishTime(unsigned NX, unsigned NY);

		const unsigned* timing;
	};

	/** Logical move VDP -> VRAM.
	  */
	template <class Mode>
	class LmmvCmd : public BlockCmd {
	public:
		LmmvCmd(VDPCmdEngine& engine, VDPVRAM& vram);
		virtual void start(const EmuTime& time);
		virtual void execute(const EmuTime& time);
	};

	/** Logical move VRAM -> VRAM.
	  */
	template <class Mode>
	class LmmmCmd : public BlockCmd {
	public:
		LmmmCmd(VDPCmdEngine& engine, VDPVRAM& vram);
		virtual void start(const EmuTime& time);
		virtual void execute(const EmuTime& time);
	};

	/** Logical move VRAM -> CPU.
	  */
	template <class Mode>
	class LmcmCmd : public BlockCmd {
	public:
		LmcmCmd(VDPCmdEngine& engine, VDPVRAM& vram);
		virtual void start(const EmuTime& time);
		virtual void execute(const EmuTime& time);
	};

	/** Logical move CPU -> VRAM.
	  */
	template <class Mode>
	class LmmcCmd : public BlockCmd {
	public:
		LmmcCmd(VDPCmdEngine& engine, VDPVRAM& vram);
		virtual void start(const EmuTime& time);
		virtual void execute(const EmuTime& time);
	};

	/** High-speed move VDP -> VRAM.
	  */
	template <class Mode>
	class HmmvCmd : public BlockCmd {
	public:
		HmmvCmd(VDPCmdEngine& engine, VDPVRAM& vram);
		virtual void start(const EmuTime& time);
		virtual void execute(const EmuTime& time);
	};

	/** High-speed move VRAM -> VRAM.
	  */
	template <class Mode>
	class HmmmCmd : public BlockCmd {
	public:
		HmmmCmd(VDPCmdEngine& engine, VDPVRAM& vram);
		virtual void start(const EmuTime& time);
		virtual void execute(const EmuTime& time);
	};

	/** High-speed move VRAM -> VRAM (Y direction only).
	  */
	template <class Mode>
	class YmmmCmd : public BlockCmd {
	public:
		YmmmCmd(VDPCmdEngine& engine, VDPVRAM& vram);
		virtual void start(const EmuTime& time);
		virtual void execute(const EmuTime& time);
	};

	/** High-speed move CPU -> VRAM.
	  */
	template <class Mode>
	class HmmcCmd : public BlockCmd {
	public:
		HmmcCmd(VDPCmdEngine& engine, VDPVRAM& vram);
		virtual void start(const EmuTime& time);
		virtual void execute(const EmuTime& time);
	};


	virtual void update(const Setting& setting);

	void executeCommand(const EmuTime& time);

	/** Finshed executing graphical operation.
	  */
	void commandDone(const EmuTime& time);

	/** Get the current command timing, depends on vdp settings (sprites, display).
	  */
	inline unsigned getTiming() {
		return likely(!brokenTiming) ? vdp.getAccessTiming() : 4;
	}

	/** Report the VDP command specified in the registers.
	  */
	void reportVdpCommand();


	/** Time at which the next operation cycle starts.
	  * A cycle consists of reading source VRAM (if applicable),
	  * reading destination VRAM (if applicable),
	  * writing destination VRAM and updating coordinates.
	  * For perfect timing each phase within a cycle should be timed
	  * explicitly, but for now we use an average execution time per
	  * cycle.
	  */
	Clock<VDP::TICKS_PER_SECOND> clock;

	/** VDP command registers.
	  */
	unsigned SX, SY, DX, DY, NX, NY; // registers that can be set by CPU
	unsigned ASX, ADX, ANX; // Temporary registers used in the VDP commands
                                // Register ASX can be read (via status register 8/9)
	byte COL, ARG, CMD, LOG;

	/** The command engine status (part of S#2).
	  * Bit 7 (TR) is set when the command engine is ready for
	  * a pixel transfer.
	  * Bit 4 (BD) is set when the boundary colour is detected.
	  * Bit 0 (CE) is set when a command is in progress.
	  */
	byte status;

	/** Used in LMCM LMMC HMMC cmds, true when CPU has read or written
	  * next byte.
	  */
	bool transfer;

	/** The VDP this command engine is part of.
	  */
	VDP& vdp;
	VDPVRAM& vram;

	RenderSettings& renderSettings;

	/** Current screen mode.
	  * 0 -> SCREEN5, 1 -> SCREEN6, 2 -> SCREEN7, 3 -> SCREEN8,
	  * -1 -> other.
	  */
	int scrMode;

	/** Flag that indicated whether extended VRAM is available
	 */
	const bool hasExtendedVRAM;

	/** Real command timing or instantaneous (broken) timing
	  */
	bool brokenTiming;

	/** Lower bound for the time when the status register will change, IOW
	  * the status register will not change before this time.
	  * Can also be EmuTime::zero -> status can change any moment
	  * or EmuTime::infinity -> this command doesn't change the status
	  */
	EmuTime statusChangeTime;

	VDPCmd* commands[16][4];
	VDPCmd* currentCommand;
	LogOp* currentOperation;

	/** Only call reportVdpCommand() when this setting is turned on
	  */
	const std::auto_ptr<BooleanSetting> cmdTraceSetting;
};

} // namespace openmsx

#endif