more mbc work

src/addressSpace.cpp

@@ -1,5 +1,6 @@
 #include "addressSpace.hpp"
 #include <iostream>
+#include <iterator>
 
 bool AddressSpace::getBootromState() const {
 	return bootromLoaded;
@@ -24,11 +25,23 @@ void AddressSpace::loadBootrom(const std::string& filename) {
 }
 
 void AddressSpace::loadGame(const std::string& filename) {
-	game.open(filename, std::ios::binary);
+	std::ifstream rom(filename, std::ios::binary);
+	rom.unsetf(std::ios::skipws);
 
-	if (!game.is_open()) {
+	if (!rom.is_open()) {
 		std::cerr << "Game was not found!\nQuitting!\n" << std::endl;
 		exit(1);
 	}
-	game.read(reinterpret_cast<char*>(memoryLayout.romBank1), ROM_BANK_SIZE * 2);
+
+	rom.seekg(0, std::ios::end);
+	const std::streampos rom_size = rom.tellg();
+	rom.seekg(0, std::ios::beg);
+
+	game.reserve(rom_size);
+	game.insert(game.begin(),
+	            std::istream_iterator<Byte>(rom),
+	            std::istream_iterator<Byte>());
+
+	memcpy(memoryLayout.romBank0, game.data(), ROM_BANK_SIZE);
+	memcpy(memoryLayout.romBankSwitch, game.data() + ROM_BANK_SIZE, ROM_BANK_SIZE);
 }

src/addressSpace.hpp

@@ -5,14 +5,17 @@
 #include <cstdint>
 #include <cstring>
 #include <string>
+#include <vector>
+
 #include "defines.hpp"
 
 class AddressSpace {
 	bool bootromLoaded = true;
 	Byte bootrom[BOOTROM_SIZE] = {0};
-	std::ifstream game;
 
 public:
+	std::vector<Byte> game;
+
 	AddressSpace() {
 		// Initialize the memory to zero
 		memoryLayout = {};
@@ -24,7 +27,7 @@ public:
 		Byte memory[0x10000];
 
 		struct {
-			Byte romBank1[ROM_BANK_SIZE]; // Mapped to 0x0000
+			Byte romBank0[ROM_BANK_SIZE]; // Mapped to 0x0000
 			Byte romBankSwitch[ROM_BANK_SIZE]; // Mapped to 0x4000
 			Byte vram[0x2000]; // Mapped to 0x8000
 			Byte externalRam[0x2000]; // Mapped to 0xA000
@@ -47,11 +50,16 @@ public:
 
 	void determineMBCInfo();
 	MBCType MBC = {};
-	uint32_t RomSize = 0;
+	uint32_t romSize = 0;
-	uint32_t RomPages = 0;
+	uint32_t romBanks = 0;
-	uint32_t ExternalRamSize = 0;
+	uint32_t externalRamSize = 0;
-	uint32_t ExternalRamPages = 0;
+	uint32_t externalRamBanks = 0;
-
+	Byte romBankRegister = 0x01;
+	Byte ramBankRegister = 0x00;
+	Byte romRamSelect = 0x00;
+	//MBC3
+	Byte latchClockData = 0x00;
+	Byte ramBankRTCRegister = 0x00;
 
 	//overload [] for echo ram and bootrom support
 	Byte operator[](const uint32_t address) const {

src/gameboy.cpp

@@ -12,6 +12,7 @@ void GameBoy::addCycles(const uint8_t ticks) {
 void GameBoy::start(std::string bootrom, std::string game) {
 	addressSpace.loadBootrom(bootrom);
 	addressSpace.loadGame(game);
+	addressSpace.determineMBCInfo();
 
 	//init some registers that won't otherwise by set
 	(*JOYP) = 0xCF;
@@ -35,18 +36,19 @@ void GameBoy::start(std::string bootrom, std::string game) {
 			}
 			ppuEnabled = (*LCDC) & 0x80;
 
-			// if (PC == 0x100)
+			if (PC >= 0xe0)
-			// 	display = true;
+				display = true;
-			// if (display) {
+			if (display) {
-			// 	printf("Cycles: %lu, Opcode: 0x%.2x PPU cycles: %lu, PPMode: %d\n", cycles, addressSpace[PC],
+				printf("Cycles: %lu, Opcode: 0x%.2x PPU cycles: %lu, PPMode: %d\n", cycles, addressSpace[PC],
-			// 	       cyclesSinceLastScanline(), currentMode);
+				       cyclesSinceLastScanline(), currentMode);
-			// 	printf("PC:0x%.2x, SP:0x%.2x\n", PC, SP);
+				printf("PC:0x%.2x, SP:0x%.2x\n", PC, SP);
-			// 	printf("AF:0x%.4x, BC:0x%.4x\n", AF.reg, BC.reg);
+				printf("AF:0x%.4x, BC:0x%.4x\n", AF.reg, BC.reg);
-			// 	printf("DE:0x%.4x, HL:0x%.4x\n", DE.reg, HL.reg);
+				printf("DE:0x%.4x, HL:0x%.4x\n", DE.reg, HL.reg);
-			// 	printf("IME:%d IF:0x%.2x IE:0x%.2x\n", IME, (*IF), (*IE));
+				printf("IME:%d IF:0x%.2x IE:0x%.2x\n", IME, (*IF), (*IE));
-			// 	printf("LCDC:%.2x STAT:0x%.2x LY:%d LYC:%d\n", (*LCDC), (*STAT), (*LY), (*LYC));
+				printf("LCDC:%.2x STAT:0x%.2x LY:%d LYC:%d\n", (*LCDC), (*STAT), (*LY), (*LYC));
-			// 	printf("\n");
+				printf("Cart type: 0x%.2x\n", addressSpace.game[0x147]);
-			// }
+				printf("\n");
+			}
 
 			opcodeResolver();
 			interruptHandler();

src/gameboy.hpp

@@ -114,6 +114,8 @@ class GameBoy {
 	uint32_t frameTime = 0;
 	const int frameDelay = 1000 / V_SYNC;
 
+	bool testMBCWrite(const Byte& address);
+
 	void opcodeResolver();
 	void incLY();
 	void ppuUpdate();

src/mbc.cpp

@@ -1 +1,44 @@
+#include "addressSpace.hpp"
 #include "gameboy.hpp"
+
+void AddressSpace::determineMBCInfo() {
+	MBC = static_cast<MBCType>(memoryLayout.romBank0[0x147]);
+	romSize = 32768 * (1 << memoryLayout.romBank0[0x147]);
+	romBanks = (1 << (memoryLayout.romBank0[0x147] + 1));
+
+	switch (memoryLayout.romBank0[0x0149]) {
+	case 0x02:
+		externalRamSize = 8196;
+		externalRamBanks = 1;
+		break;
+	case 0x03:
+		externalRamSize = 32768;
+		externalRamBanks = 4;
+		break;
+	case 0x04:
+		externalRamSize = 131072;
+		externalRamBanks = 16;
+		break;
+	case 0x05:
+		externalRamSize = 65536;
+		externalRamBanks = 8;
+		break;
+	default:
+		externalRamSize = 0;
+		externalRamBanks = 0;
+		break;
+	}
+
+	if (MBC == MBC2 || MBC2Battery) {
+		//only the lower 4 bits are usable
+		externalRamSize = 512;
+	}
+}
+
+bool GameBoy::testMBCWrite(const Byte& address) {
+	const Byte* ptr = &address;
+	if (ptr >= &addressSpace[0x0] && ptr <= &addressSpace[0x7FFF])
+		return true;
+	return false;
+}
+