// Copyright (c) 1995 - 2026 kio@little-bat.de
// BSD-2-Clause license
// https://opensource.org/licenses/BSD-2-Clause

#pragma once
#include "Item.h"
#include "Memory.h"
#include "zxsp_types.h"


namespace zxsp
{

class Mmu : public Item
{
protected:
	Z80* cpu;
	union
	{
		Ula*	 ula;
		UlaZxsp* ula_zxsp;
	};
	MemoryPtr ram;
	MemoryPtr rom;

public:
	virtual void mapMem() {} // map memory in models which have expandable memory

	// RAMDIS und ROMDIS behandeln, falls vorhanden:
	// Hier sind die Dummy-Funktionen, falls ein Gerät das jeweilige Signal nicht hat.
	// z.B.: ZX80 hat kein ROMDIS, Speccies haben kein RAMDIS
	// Sonst muss es in der jeweiligen MMU reimplementiert sein.
	// ramCS() und romCS() der MMU dürfen prev()->ramCS()/prev()->romCS() nicht mehr aufrufen!
	// The calling chains for ramCS and romCS end here (Mmu).
	// Note: dass wir hier ramcs/romcs aktualisieren, ist überflüssig.
	// Note: ramCS() wird z.Zt. gar nicht benutzt, da Ram-Erweiterungen z.Zt. das interne Ram des Computers erweitern.
	// Note: +3/+2A: statt romCS1 und romCS2 wird romCS benutzt
	//
	virtual void ramCS(bool f) override
	{
		ramdis_in = f;
		logline("Mmu.ramCS(%i)", f);
	} // ZX80, ZX81

	virtual void romCS(bool f) override
	{
		romdis_in = f;
		logline("Mmu.romCS(%i)", f);
	} // ZX81, ZXSP, ZX128, +2

	/*  note:   RAMCS:  input '1':    activated: disable internal Ram (ZXSP)
						input high Z: not activated
				ROMCS:  input '1':    activated: disable internal Rom (ZXSP,128,+2)
						input high Z: not activated
				ROMCS1: input '1':    activated: disable presumably lower internal Rom (ZX+3/+2A)
						input high Z: not activated
				ROMCS2: input '1':    activated: disable presumably upper internal Rom (ZX+3/+2A)
						input high Z: not activated

		i can't imagine a scenario where setting CS1 and CS2 differently makes sense.
		ROMCS is used for +3/+2A for simplicity as well.

		Pageing of the internal ram and rom (if applicable) is handled by Item::Mmu.
		In general items should not actively unmap their memory as result of incoming ROMCS.
		Instead they should trust that the sender will map it's rom into the Z80's memory space.
		While their backside ROMCS is active, items must not page in their memory, just store values written to their
	   registers only.
	*/

	virtual bool  hasPort7ffd() const volatile noexcept { return no; }
	virtual void  setPort7ffd(uint8) {} // nop
	virtual uint8 getPort7ffd() const volatile { return 0xFF; }

	virtual bool  hasPort1ffd() const volatile noexcept { return no; }
	virtual void  setPort1ffd(uint8) {} // nop
	virtual uint8 getPort1ffd() const volatile { return 0xFF; }

	virtual bool  hasPortF4() const volatile noexcept { return no; }
	virtual void  setPortF4(uint8) {} // nop
	virtual uint8 getPortF4() const volatile { return 0xFF; }

protected:
	Mmu(Machine*, isa_id, cstr o_addr, cstr i_addr);
	~Mmu() override = default;

	// Item interface:
	void powerOn(/*t=0*/ int32 cc) override;
	// void	reset			(Time t, int32 cc) override;
	// void	input			(Time t, int32 cc, uint16 addr, uint8& byte, uint8& mask) override;
	// void	output			(Time t, int32 cc, uint16 addr, uint8 byte) override;
	// void	audioBufferEnd	(Time t) override;
	// void	videoFrameEnd	(int32 cc) override;
	uint8 handleRomPatch(uint16, uint8 o) override { return o; }		  // returns opcode read
	uint8 readMemory(Time, int32, uint16, uint8 n) override { return n; } // returns byte read
	void  writeMemory(Time, int32, uint16, uint8) override {}
};

} // namespace zxsp