fceugx/source/fceultra/boards/mmc1.cpp

/* FCE Ultra - NES/Famicom Emulator
 *
 * Copyright notice for this file:
 *  Copyright (C) 1998 BERO
 *  Copyright (C) 2002 Xodnizel
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#include "mapinc.h"

static void GenMMC1Power(void);
static void GenMMC1Init(CartInfo *info, int prg, int chr, int wram, int bram);

static uint8 DRegs[4];
static uint8 Buffer, BufferShift;

static uint32 WRAMSIZE;
static uint32 NONBRAMSIZE; // size of non-battery-backed portion of WRAM

static void (*MMC1CHRHook4)(uint32 A, uint8 V);
static void (*MMC1PRGHook16)(uint32 A, uint8 V);

static uint8 *WRAM = NULL;
static uint8 *CHRRAM = NULL;
static int is155, is171;

static DECLFW(MBWRAM) {
	if (!(DRegs[3] & 0x10) || is155)
		Page[A >> 11][A] = V;  // WRAM is enabled.
}

static DECLFR(MAWRAM) {
	if ((DRegs[3] & 0x10) && !is155)
		return X.DB;          // WRAM is disabled
	return(Page[A >> 11][A]);
}

static void MMC1CHR(void) {
	if (WRAMSIZE > 0x2000) {
		if (WRAMSIZE > 0x4000)
			setprg8r(0x10, 0x6000, (DRegs[1] >> 2) & 3);
		else
			setprg8r(0x10, 0x6000, (DRegs[1] >> 3) & 1);
	}

	if (MMC1CHRHook4) {
		if (DRegs[0] & 0x10) {
			MMC1CHRHook4(0x0000, DRegs[1]);
			MMC1CHRHook4(0x1000, DRegs[2]);
		} else {
			MMC1CHRHook4(0x0000, (DRegs[1] & 0xFE));
			MMC1CHRHook4(0x1000, DRegs[1] | 1);
		}
	} else {
		if (DRegs[0] & 0x10) {
			setchr4(0x0000, DRegs[1]);
			setchr4(0x1000, DRegs[2]);
		} else
			setchr8(DRegs[1] >> 1);
	}
}

static void MMC1PRG(void) {
	uint8 offs_16banks = DRegs[1] & 0x10;
	uint8 prg_reg = DRegs[3] & 0xF; //homebrewers arent allowed to use more banks on MMC1. use another mapper.
	if (MMC1PRGHook16) {
		switch (DRegs[0] & 0xC) {
		case 0xC:
			MMC1PRGHook16(0x8000, (prg_reg + offs_16banks));
			MMC1PRGHook16(0xC000, 0xF + offs_16banks);
			break;
		case 0x8:
			MMC1PRGHook16(0xC000, (prg_reg + offs_16banks));
			MMC1PRGHook16(0x8000, offs_16banks);
			break;
		case 0x0:
		case 0x4:
			MMC1PRGHook16(0x8000, ((prg_reg & ~1) + offs_16banks));
			MMC1PRGHook16(0xc000, ((prg_reg & ~1) + offs_16banks + 1));
			break;
		}
	} else {
		switch (DRegs[0] & 0xC) {
		case 0xC:
			setprg16(0x8000, (prg_reg + offs_16banks));
			setprg16(0xC000, 0xF + offs_16banks);
			break;
		case 0x8:
			setprg16(0xC000, (prg_reg + offs_16banks));
			setprg16(0x8000, offs_16banks);
			break;
		case 0x0:
		case 0x4:
			setprg16(0x8000, ((prg_reg & ~1) + offs_16banks));
			setprg16(0xc000, ((prg_reg & ~1) + offs_16banks + 1));
			break;
		}
	}
}

static void MMC1MIRROR(void) {
	if (!is171)
		switch (DRegs[0] & 3) {
		case 2: setmirror(MI_V); break;
		case 3: setmirror(MI_H); break;
		case 0: setmirror(MI_0); break;
		case 1: setmirror(MI_1); break;
		}
}

static uint64 lreset;
static DECLFW(MMC1_write) {
	int n = (A >> 13) - 4;

	/* The MMC1 is busy so ignore the write. */
	/* As of version FCE Ultra 0.81, the timestamp is only
		increased before each instruction is executed(in other words
		precision isn't that great), but this should still work to
		deal with 2 writes in a row from a single RMW instruction.
	*/
	if ((timestampbase + timestamp) < (lreset + 2))
		return;
//	FCEU_printf("Write %04x:%02x\n",A,V);
	if (V & 0x80) {
		DRegs[0] |= 0xC;
		BufferShift = Buffer = 0;
		MMC1PRG();
		lreset = timestampbase + timestamp;
		return;
	}

	Buffer |= (V & 1) << (BufferShift++);

	if (BufferShift == 5) {
		DRegs[n] = Buffer;
		BufferShift = Buffer = 0;
		switch (n) {
		case 0: MMC1MIRROR(); MMC1CHR(); MMC1PRG(); break;
		case 1: MMC1CHR(); MMC1PRG(); break;
		case 2: MMC1CHR(); break;
		case 3: MMC1PRG(); break;
		}
	}
}

static void MMC1_Restore(int version) {
	MMC1MIRROR();
	MMC1CHR();
	MMC1PRG();
	lreset = 0;		// timestamp(base) is not stored in save states.
}

static void MMC1CMReset(void) {
	int i;

	for (i = 0; i < 4; i++)
		DRegs[i] = 0;
	Buffer = BufferShift = 0;
	DRegs[0] = 0x1F;

	DRegs[1] = 0;
	DRegs[2] = 0;	// Should this be something other than 0?
	DRegs[3] = 0;

	MMC1MIRROR();
	MMC1CHR();
	MMC1PRG();
}

static int DetectMMC1WRAMSize(CartInfo *info, int *bs) {
	int ws = 8;
	switch (info->CRC32) {
	case 0xc6182024:	// Romance of the 3 Kingdoms
	case 0xabbf7217:	// ""        "" (J) (PRG0)
	case 0xccf35c02:	// ""        "" (J) (PRG1)
	case 0x2225c20f:	// Genghis Khan
	case 0xfb69743a:	// ""        "" (J)
	case 0x4642dda6:	// Nobunaga's Ambition
	case 0x3f7ad415:	// ""        "" (J) (PRG0)
	case 0x2b11e0b0:	// ""        "" (J) (PRG1)
		*bs = 8;
		ws = 16;
		break;
	case 0xb8747abf:	// Best Play Pro Yakyuu Special (J) (PRG0)
	case 0xc3de7c69:	// ""        "" (J) (PRG1)
	case 0xc9556b36:	// Final Fantasy I & II (J) [!]
		*bs = 32;
		ws = 32;
		break;
	default:
		if(info->ines2) {
			ws = (info->wram_size + info->battery_wram_size) / 1024;
			*bs = info->battery_wram_size / 1024;
			// we only support sizes between 8K and 32K
			if (ws > 0 && ws < 8) ws = 8;
			if (ws > 32) ws = 32;
			if (*bs > ws) *bs = ws;
		}
	}
	if (ws > 8)
		FCEU_printf(" >8KB external WRAM present.  Use NES 2.0 if you hack the ROM image.\n");
	return ws;
}

static uint32 NWCIRQCount;
static uint8 NWCRec;
#define NWCDIP 0xE

static void NWCIRQHook(int a) {
	if (!(NWCRec & 0x10)) {
		NWCIRQCount += a;
		if ((NWCIRQCount | (NWCDIP << 25)) >= 0x3e000000) {
			NWCIRQCount = 0;
			X6502_IRQBegin(FCEU_IQEXT);
		}
	}
}

static void NWCCHRHook(uint32 A, uint8 V) {
	if ((V & 0x10)) { // && !(NWCRec&0x10))
		NWCIRQCount = 0;
		X6502_IRQEnd(FCEU_IQEXT);
	}

	NWCRec = V;
	if (V & 0x08)
		MMC1PRG();
	else
		setprg32(0x8000, (V >> 1) & 3);
}

static void NWCPRGHook(uint32 A, uint8 V) {
	if (NWCRec & 0x8)
		setprg16(A, 8 | (V & 0x7));
	else
		setprg32(0x8000, (NWCRec >> 1) & 3);
}

static void NWCPower(void) {
	GenMMC1Power();
	setchr8r(0, 0);
}

void Mapper105_Init(CartInfo *info) {
	GenMMC1Init(info, 256, 256, 8, 0);
	MMC1CHRHook4 = NWCCHRHook;
	MMC1PRGHook16 = NWCPRGHook;
	MapIRQHook = NWCIRQHook;
	info->Power = NWCPower;
}

static void GenMMC1Power(void) {
	lreset = 0;
	SetWriteHandler(0x8000, 0xFFFF, MMC1_write);
	SetReadHandler(0x8000, 0xFFFF, CartBR);

	if (WRAMSIZE) {
		FCEU_CheatAddRAM(8, 0x6000, WRAM);

		// clear non-battery-backed portion of WRAM
		if (NONBRAMSIZE)
			FCEU_MemoryRand(WRAM, NONBRAMSIZE, true);

		SetReadHandler(0x6000, 0x7FFF, MAWRAM);
		SetWriteHandler(0x6000, 0x7FFF, MBWRAM);
		setprg8r(0x10, 0x6000, 0);
	}

	MMC1CMReset();
}

static void GenMMC1Close(void) {
	if (CHRRAM)
		FCEU_gfree(CHRRAM);
	if (WRAM)
		FCEU_gfree(WRAM);
	CHRRAM = WRAM = NULL;
}

static void GenMMC1Init(CartInfo *info, int prg, int chr, int wram, int bram) {
	is155 = 0;

	info->Close = GenMMC1Close;
	MMC1PRGHook16 = MMC1CHRHook4 = 0;
	WRAMSIZE = wram * 1024;
	NONBRAMSIZE = (wram - bram) * 1024;
	PRGmask16[0] &= (prg >> 14) - 1;
	CHRmask4[0] &= (chr >> 12) - 1;
	CHRmask8[0] &= (chr >> 13) - 1;

	if (WRAMSIZE) {
		WRAM = (uint8*)FCEU_gmalloc(WRAMSIZE);
		SetupCartPRGMapping(0x10, WRAM, WRAMSIZE, 1);
		AddExState(WRAM, WRAMSIZE, 0, "WRAM");
		if (bram) {
			info->SaveGame[0] = WRAM + NONBRAMSIZE;
			info->SaveGameLen[0] = bram * 1024;
		}
	}
	if (!chr) {
		CHRRAM = (uint8*)FCEU_gmalloc(8192);
		SetupCartCHRMapping(0, CHRRAM, 8192, 1);
		AddExState(CHRRAM, 8192, 0, "CHRR");
	}
	AddExState(DRegs, 4, 0, "DREG");

	info->Power = GenMMC1Power;
	GameStateRestore = MMC1_Restore;
	AddExState(&lreset, 8, 1, "LRST");
	AddExState(&Buffer, 1, 1, "BFFR");
	AddExState(&BufferShift, 1, 1, "BFRS");
}

void Mapper1_Init(CartInfo *info) {
	int bs = info->battery ? 8 : 0;
	int ws = DetectMMC1WRAMSize(info, &bs);
	GenMMC1Init(info, 512, 256, ws, bs);
}

/* Same as mapper 1, without respect for WRAM enable bit. */
void Mapper155_Init(CartInfo *info) {
	GenMMC1Init(info, 512, 256, 8, info->battery ? 8 : 0);
	is155 = 1;
}

/* Same as mapper 1, with different (or without) mirroring control. */
/* Kaiser KS7058 board, KS203 custom chip */
void Mapper171_Init(CartInfo *info) {
	GenMMC1Init(info, 32, 32, 0, 0);
	is171 = 1;
}

void SAROM_Init(CartInfo *info) {
	GenMMC1Init(info, 128, 64, 8, info->battery ? 8 : 0);
}

void SBROM_Init(CartInfo *info) {
	GenMMC1Init(info, 128, 64, 0, 0);
}

void SCROM_Init(CartInfo *info) {
	GenMMC1Init(info, 128, 128, 0, 0);
}

void SEROM_Init(CartInfo *info) {
	GenMMC1Init(info, 32, 64, 0, 0);
}

void SGROM_Init(CartInfo *info) {
	GenMMC1Init(info, 256, 0, 0, 0);
}

void SKROM_Init(CartInfo *info) {
	GenMMC1Init(info, 256, 64, 8, info->battery ? 8 : 0);
}

void SLROM_Init(CartInfo *info) {
	GenMMC1Init(info, 256, 128, 0, 0);
}

void SL1ROM_Init(CartInfo *info) {
	GenMMC1Init(info, 128, 128, 0, 0);
}

/* Begin unknown - may be wrong - perhaps they use different MMC1s from the
	similarly functioning boards?
*/

void SL2ROM_Init(CartInfo *info) {
	GenMMC1Init(info, 256, 256, 0, 0);
}

void SFROM_Init(CartInfo *info) {
	GenMMC1Init(info, 256, 256, 0, 0);
}

void SHROM_Init(CartInfo *info) {
	GenMMC1Init(info, 256, 256, 0, 0);
}

/* End unknown  */
/*              */
/*              */

void SNROM_Init(CartInfo *info) {
	GenMMC1Init(info, 256, 0, 8, info->battery ? 8 : 0);
}

void SOROM_Init(CartInfo *info) {
	GenMMC1Init(info, 256, 0, 16, info->battery ? 8 : 0);
}