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

/*
	Manage the paging control register of a ZX Spectrum+ 128K
*/

#include "Mmu128k.h"
#include "Machine.h"
#include "Ula/Ula128k.h"
#include "Z80/Z80.h"
#include "ZxInfo.h"
#include "unix/FD.h"


namespace zxsp
{

// ZX Spectrum 128K / +2 Memory Control
#define o_addr_128 "0---.----.----.--0-" // üblicher Port: 0x7ffd

// zx128k and +2: ram pages 1,3,5 and 7 are contended


/*	creator for use by derived classes:
	• MmuPlus3
*/
Mmu128k::Mmu128k(Machine* m, isa_id id, cstr o_addr, cstr i_addr) : Mmu(m, id, o_addr, i_addr)
{
	xlogIn("new Mmu128k");
}


Mmu128k::Mmu128k(Machine* m) : Mmu(m, isa_Mmu128k, o_addr_128, nullptr) { xlogIn("new Mmu128k"); }


void Mmu128k::powerOn(int32 cc)
{
	xlogIn("Mmu128k:init");

	Mmu::powerOn(cc);
	assert(ram.count() == 0x20000);
	assert(rom.count() == 0x08000);
	assert(ula->isA(isa_Ula128k));
	//	setPort7ffd(0x00);
	port_7ffd = 0;
	page_mem_128k();
}


void Mmu128k::reset(Time t, int32 cc)
{
	xlogIn("Mmu128k:reset");

	Mmu::reset(t, cc);
	setPort7ffd(0x00);
}


/*	page in selected rom
	assumed: not (yet) locked to 48k
*/
inline void Mmu128k::page_rom_128k()
{
	assert(!romdis_in);

	int i = port_7ffd & 0x10;
	cpu->mapRom(0x0000, 0x4000, &rom[i * 0x400], nullptr, 0);
}


/*	page in selected ram at $c000
	assumed: not (yet) locked to 48k
	ram banks 1,3,5,7 are contended
*/
inline void Mmu128k::page_ram_128k()
{
	int n = port_7ffd & 0x07;
	if (n & 1) cpu->mapRam(3 * 0x4000, 0x4000, &ram[n * 0x4000], ula_zxsp->getWaitmap(), ula_zxsp->getWaitmapSize());
	else cpu->mapRam(3 * 0x4000, 0x4000, &ram[n * 0x4000], nullptr, 0);
}


/*	page in rom and ram pages
	assumed: not locked to 48k
	ram banks 1,3,5,7 are contended
*/
inline void Mmu128k::page_mem_128k()
{
	page_ram_128k();
	cpu->mapRam(2 * 0x4000, 0x4000, &ram[2 * 0x4000], nullptr, 0);
	cpu->mapRam(1 * 0x4000, 0x4000, &ram[5 * 0x4000], ula_zxsp->getWaitmap(), ula_zxsp->getWaitmapSize());
	if (!romdis_in) page_rom_128k();
}


/*	set port $7ffd
	override 48k lock
	also calls Ula128k::setPort7ffd()
*/
void Mmu128k::setPort7ffd(uint8 byte)
{
	assert(dynamic_cast<Ula128k*>(ula));

	port_7ffd = byte;
	page_mem_128k();
	static_cast<Ula128k*>(ula)->setPort7ffd(byte);
}


void Mmu128k::output(Time, int32 /*cc*/, uint16 /*addr*/, uint8 byte)
{
	xlogIn("Mmu128k:Output($%02x)", uint(byte));

	if (port7ffdIsLocked()) return; // mmu port disabled.

	uint8 toggled = port_7ffd ^ byte;
	port_7ffd	  = byte;

	//	if( toggled&0x08 )									// screen changed? => handled by Ula128k
	if (toggled & 0x07) page_ram_128k();			   // ram page at $c000 changed?
	if (toggled & 0x10 && !romdis_in) page_rom_128k(); // rom page changed?
}


//  ROMCS Eingang wurde aktiviert/deaktiviert
//	MMU.ROMCS handles paging of internal ROM.
//	=> no need to forward it's own ROMCS state as well.
//
void Mmu128k::romCS(bool f)
{
	if (f == romdis_in) return; // no change
	romdis_in = f;
	if (f) return; // rom disabled, caller will map it's own rom, no need to unmap it here

	page_rom_128k();
}

} // namespace zxsp