small fixes

src/addressSpace.hpp

@@ -33,9 +33,9 @@ public:
 		Byte oam[0xA0]; //Mapped to 0xFE00
 		Byte notUsable[0x60]; //Mapped to 0xFEA0
 		//General purpose hardware registers
-		Byte JOYP;
+		Byte JOYP = 0xCF;
 		Byte SB;
-		Byte SC;
+		Byte SC = 0x7E;
 		Byte DIV;
 		//Timer registers
 		Byte TIMA;
@@ -263,8 +263,11 @@ public:
 			return (*MBCRead(address));
 		if (address < 0xA000)
 			return memoryLayout.vram[address - 0x8000];
-		if (address < 0xC000)
+		if (address < 0xC000) {
+			if (externalRamSize == 0)
+				return dummyVal;
 			return memoryLayout.externalRam[address - 0xA000];
+		}
 		if (address < 0xD000)
 			return memoryLayout.memoryBank1[address - 0xC000];
 		if (address < 0xE000)

src/gameboy.cpp

@@ -51,51 +51,113 @@ void GameBoy::start(const std::string& bootrom, const std::string& game) {
 	addressSpace.determineMBCInfo();
 	addressSpace.createRamBank();
 
-	//init some registers that won't otherwise by set
-	addressSpace.memoryLayout.JOYP = 0xDF;
-	addressSpace.memoryLayout.SC = 0x7E;
-
 	bool quit = false;
 	bool setIME = false;
-	bool display = false;
+	bool debug = false;
 
 	while (!quit) {
 		// Event loop
 		while (SDL_PollEvent(&event)) {
-			if (event.type == SDL_QUIT) {
+			switch (event.type) {
+			case SDL_QUIT:
 				quit = true;
-			}
+				break;
-			if (event.type == SDL_KEYUP) {
+			case SDL_KEYDOWN:
-				display = true;
+				switch (event.key.keysym.sym) {
+				case SDLK_a:
+					joypadInput.LEFT = true;
+					break;
+				case SDLK_d:
+					joypadInput.RIGHT = true;
+					break;
+				case SDLK_w:
+					joypadInput.UP = true;
+					break;
+				case SDLK_s:
+					joypadInput.DOWN = true;
+					break;
+				case SDLK_k:
+					joypadInput.A = true;
+					break;
+				case SDLK_l:
+					joypadInput.B = true;
+					break;
+				case SDLK_o:
+					joypadInput.SELECT = true;
+					break;
+				case SDLK_p:
+					joypadInput.START = true;
+					break;
+				case SDLK_h:
+					debug = true;
+					break;
+				default:
+					break;
+				}
+				break;
+			case SDL_KEYUP:
+				switch (event.key.keysym.sym) {
+				case SDLK_a:
+					joypadInput.LEFT = false;
+					break;
+				case SDLK_d:
+					joypadInput.RIGHT = false;
+					break;
+				case SDLK_w:
+					joypadInput.UP = false;
+					break;
+				case SDLK_s:
+					joypadInput.DOWN = false;
+					break;
+				case SDLK_k:
+					joypadInput.A = false;
+					break;
+				case SDLK_l:
+					joypadInput.B = false;
+					break;
+				case SDLK_o:
+					joypadInput.SELECT = false;
+					break;
+				case SDLK_p:
+					joypadInput.START = false;
+					break;
+				case SDLK_h:
+					debug = false;
+					break;
+				default:
+					break;
+				}
+				break;
+			default:
+				break;
 			}
 		}
 
 		while (!rendered) {
+			joypadHandler();
 			if (PC > 0xFF && addressSpace.getBootromState()) {
 				addressSpace.unmapBootrom();
 			}
 			ppuEnabled = addressSpace.memoryLayout.LCDC & 0x80;
 			prevTMA = addressSpace.memoryLayout.TMA;
 
-			if (PC == 0x100)
+			if (debug) {
-				display = true;
+				printf(
-			if (display) {
+					"A: %.2X F: %.2X B: %.2X C: %.2X D: %.2X E: %.2X H: %.2X L: %.2X SP: %.4X PC: 00:%.4X (%.2X %.2X %.2X %.2X)\n",
-				// printf("A: %.2X F: %.2X B: %.2X C: %.2X D: %.2X E: %.2X H: %.2X L: %.2X SP: %.4X PC: 00:%.4X (%.2X %.2X %.2X %.2X)\n",
+					AF.hi, AF.lo, BC.hi, BC.lo, DE.hi, DE.lo, HL.hi, HL.lo, SP, PC, readOnlyAddressSpace[PC],
-				// AF.hi, AF.lo, BC.hi, BC.lo, DE.hi, DE.lo, HL.hi, HL.lo, SP, PC, readOnlyAddressSpace[PC],
+					readOnlyAddressSpace[PC + 1], readOnlyAddressSpace[PC + 2], readOnlyAddressSpace[PC + 3]);
-				// readOnlyAddressSpace[PC + 1], readOnlyAddressSpace[PC + 2], readOnlyAddressSpace[PC + 3]);
 
 
-				// 	printf("Cycles: %lu, Opcode: 0x%.2x PPU cycles: %lu, PPMode: %d\n", cycles, readOnlyAddressSpace[PC],
+				// printf("Cycles: %lu, Opcode: 0x%.2x PPU cycles: %lu, PPMode: %d\n", cycles, readOnlyAddressSpace[PC],
-				// 	       cyclesSinceLastScanline(), currentMode);
+				//        cyclesSinceLastScanline(), currentMode);
-				// 	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("PC:0x%.4x, SP:0x%.4x\n", PC, SP);
+				// printf("PC:0x%.4x, SP:0x%.4x\n", PC, SP);
-				// 	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("\n");
 			}
 
-
 			if (!halted) {
 				opcodeResolver();
 				addressSpace.MBCUpdate();

src/gameboy.hpp

@@ -70,6 +70,7 @@ class GameBoy {
 	const int frameDelay = 1000 / V_SYNC;
 
 	Input joypadInput;
+	void joypadHandler();
 
 	void opcodeResolver();
 

src/joypad.cpp

@@ -0,0 +1,44 @@
+#include "gameboy.hpp"
+#include "defines.hpp"
+
+void GameBoy::joypadHandler() {
+	const Byte joyP = addressSpace.memoryLayout.JOYP;
+	const bool buttons = (joyP & 0x20) == 0;
+	const bool dpad = (joyP & 0x10) == 0;
+
+	addressSpace.memoryLayout.JOYP |= 0xCF;
+
+	if (buttons && !dpad) {
+		if (joypadInput.A)
+			addressSpace.memoryLayout.JOYP &= ~0x1;
+		if (joypadInput.B)
+			addressSpace.memoryLayout.JOYP &= ~0x2;
+		if (joypadInput.SELECT)
+			addressSpace.memoryLayout.JOYP &= ~0x4;
+		if (joypadInput.START)
+			addressSpace.memoryLayout.JOYP &= ~0x8;
+	}
+	if (!buttons && dpad) {
+		if (joypadInput.RIGHT)
+			addressSpace.memoryLayout.JOYP &= ~0x1;
+		if (joypadInput.LEFT)
+			addressSpace.memoryLayout.JOYP &= ~0x2;
+		if (joypadInput.UP)
+			addressSpace.memoryLayout.JOYP &= ~0x4;
+		if (joypadInput.DOWN)
+			addressSpace.memoryLayout.JOYP &= ~0x8;
+	}
+
+	if (buttons && dpad) {
+		addressSpace.memoryLayout.JOYP |= 0xCF;
+
+		if (joypadInput.RIGHT && joypadInput.A)
+			addressSpace.memoryLayout.JOYP &= ~0x1;
+		if (joypadInput.LEFT && joypadInput.B)
+			addressSpace.memoryLayout.JOYP &= ~0x2;
+		if (joypadInput.UP && joypadInput.SELECT)
+			addressSpace.memoryLayout.JOYP &= ~0x4;
+		if (joypadInput.DOWN && joypadInput.START)
+			addressSpace.memoryLayout.JOYP &= ~0x8;
+	}
+}

src/main.cpp

@@ -11,8 +11,8 @@ void runJSONTests(GameBoy* gb);
 
 int main(int argc, char** argv) {
 	if (argc != 3) {
-		std::cout << "Usage: " << argv[0] << " <bios> <game>" << std::endl;
+		std::cerr << "Usage: " << argv[0] << " <bios> <game>\n" << std::endl;
-		return -1;
+		return 1;
 	}
 
 	auto* gb = new GameBoy();

src/mbc.cpp

@@ -5,7 +5,8 @@ void AddressSpace::determineMBCInfo() {
 	romSize = 32768 * (1 << memoryLayout.romBank0[0x147]);
 	romBanks = 1 << (memoryLayout.romBank0[0x147] + 1);
 
-	switch (memoryLayout.romBank0[0x0149]) {
+	const Byte ramSize = memoryLayout.romBank0[0x0149];
+	switch (ramSize) {
 	case 0x02:
 		externalRamSize = 8196;
 		externalRamBanks = 1;
@@ -96,23 +97,19 @@ void AddressSpace::MBCUpdate() {
 }
 
 void AddressSpace::loadRomBank() {
-	Byte* old = memoryLayout.romBankSwitch;
 	memoryLayout.romBankSwitch = game.data() + (ROM_BANK_SIZE * selectedRomBank);
-	if (old != memoryLayout.romBankSwitch)
-		printf("\n");
 }
 
 void AddressSpace::createRamBank() {
-	if (externalRamSize)
+	if (externalRamSize) {
 		cartridgeRam = new Byte[externalRamSize];
+		memoryLayout.externalRam = cartridgeRam;
+	}
 }
 
 void AddressSpace::loadRamBank() {
-	Byte* old = memoryLayout.externalRam;
 	if (cartridgeRam != nullptr)
 		memoryLayout.externalRam = cartridgeRam + (RAM_BANK_SIZE * selectedExternalRamBank);
-	if (old != memoryLayout.externalRam)
-		printf("\n");
 }
 
 

src/ppu.cpp

@@ -336,7 +336,7 @@ void GameBoy::drawLine() {
 					const uint32_t finalColor = getColourFromPalette(paletteColor);
 					oamPixels[pixel] = finalColor;
 				}
-				else {
+				else if (oamPixels[pixel] == 0) {
 					oamPixels[pixel] = currentLinePixels[pixel];
 				}
 			}