YayIguess/GBpp
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

prelim mbc work

Browse Source
This commit is contained in:
Braiden Gent
2024-03-30 17:27:49 -07:00
parent 7854862850
commit 0bcf339ebf
9 changed files with 216 additions and 161 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
CMakeLists.txt
View File

@@ -12,5 +12,8 @@ add_executable(GBpp src/main.cpp
src/ppu.cpp
src/timing.cpp
src/extendedOpcodeResolver.cpp
src/mbc.cpp
src/addressSpace.cpp
src/addressSpace.hpp
)
target_link_libraries(GBpp ${SDL2_LIBRARIES})

34
src/addressSpace.cpp Normal file
View File

@@ -0,0 +1,34 @@
#include "addressSpace.hpp"
#include <iostream>
bool AddressSpace::getBootromState() const {
return bootromLoaded;
}
void AddressSpace::unmapBootrom() {
bootromLoaded = false;
}
void AddressSpace::mapBootrom() {
bootromLoaded = true;
}
void AddressSpace::loadBootrom(const std::string& filename) {
std::ifstream file;
if (const uintmax_t size = std::filesystem::file_size(filename); size != 256) {
std::cerr << "Bootrom was an unexpected size!\nQuitting!\n" << std::endl;
exit(1);
}
file.open(filename, std::ios::binary);
file.read(reinterpret_cast<char*>(bootrom), BOOTROM_SIZE);
}
void AddressSpace::loadGame(const std::string& filename) {
game.open(filename, std::ios::binary);
if (!game.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);
}

77
src/addressSpace.hpp Normal file
View File

@@ -0,0 +1,77 @@
#ifndef ADDRESSSPACE_HPP
#define ADDRESSSPACE_HPP
#include <fstream>
#include <filesystem>
#include <cstdint>
#include <cstring>
#include <string>
#include "defines.hpp"
class AddressSpace {
bool bootromLoaded = true;
Byte bootrom[BOOTROM_SIZE] = {0};
std::ifstream game;
public:
AddressSpace() {
// Initialize the memory to zero
memoryLayout = {};
std::memset(memoryLayout.memory, 0, sizeof(memoryLayout.memory));
}
// Nested union for the memory layout
union MemoryLayout {
Byte memory[0x10000];
struct {
Byte romBank1[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
Byte memoryBank1[0x1000]; // Mapped to 0xC000
Byte memoryBank2[0x1000]; // Mapped to 0xD000
Byte echoRam[0x1E00]; // Mapped to 0xE000 (Echo RAM, mirrors 0xC000 to 0xDFFF)
Byte spriteAttributeTable[0xA0]; // Mapped to 0xFE00
Byte notUsable[0x60]; // Mapped to 0xFEA0
Byte io[0x80]; // Mapped to 0xFF00, 0xFF0F is interrupt flag
Byte specialRam[0x7F]; // Mapped to 0xFF80
Byte interuptEnableReg; // Mapped to 0xFFFF
};
} memoryLayout{};
void unmapBootrom();
void mapBootrom();
bool getBootromState() const;
void loadBootrom(const std::string& filename);
void loadGame(const std::string& filename);
void determineMBCInfo();
MBCType MBC = {};
uint32_t RomSize = 0;
uint32_t RomPages = 0;
uint32_t ExternalRamSize = 0;
uint32_t ExternalRamPages = 0;
//overload [] for echo ram and bootrom support
Byte operator[](const uint32_t address) const {
if (address >= 0xE000 && address < 0xFE00)
return memoryLayout.echoRam[address - 0x2000];
if (address < 0x0100 && bootromLoaded)
return bootrom[address];
return memoryLayout.memory[address];
}
Byte& operator[](const uint32_t address) {
if (address >= 0xE000 && address < 0xFE00)
return memoryLayout.echoRam[address - 0x2000];
if (address < 0x0100 && bootromLoaded)
return bootrom[address];
return memoryLayout.memory[address];
}
};
#endif //ADDRESSSPACE_HPP

45
src/defines.hpp
View File

@@ -46,5 +46,50 @@
#define SCANLINE_OAM_FREQ 80 //PPU_MODE 2
#define SCANLINE_VRAM_FREQ 80 //PPU_MODE 3
//two bits per colour
enum Colour {
black = 0b11,
darkGray = 0b10,
lightGray = 0b01,
white = 0b00
};
enum MBCType {
romOnly = 0x00,
MBC1 = 0x01,
MBC1Ram = 0x02,
MBC1RamBattery = 0x03,
MBC2 = 0x05,
MBC2Battery = 0x06,
RomRam = 0x08, //unused
RomRamBattery = 0x09, //unused
MMM01 = 0x0B, //multigame roms only
MMM01Ram = 0x0C,
MMM01RamBattery = 0x0D,
MBC3TimerBattery = 0x0F,
MBC3TimerRamBattery = 0x10,
MBC3 = 0x11,
MBC3Ram = 0x12, // MBC3 with 64 KiB of SRAM refers to MBC30, used only in Pocket Monsters: Crystal Version.
MBC3RamBattery = 0x13,
MBC5 = 0x19,
MBC5Ram = 0x1A,
MBC5RamBattery = 0x1B,
MBC5Rumble = 0x1C,
MBC5RumbleRam = 0x1D,
MBC5RumbleRamBattery = 0x1E,
MBC6 = 0x20,
MBC7SensorRumbleRamBattery = 0x22,
PocketCamera = 0xFC,
BandaiTama5 = 0xFD,
HuC3 = 0xFE,
HuC1RamBattery = 0xFF
};
enum PPUMode {
mode0, // Horizontal Blank (Mode 0): No access to video RAM, occurs during horizontal blanking period.
mode1, // Vertical Blank (Mode 1): No access to video RAM, occurs during vertical blanking period.
mode2, // OAM Search (Mode 2): Access to OAM (Object Attribute Memory) only, sprite evaluation.
mode3 // Pixel Transfer (Mode 3): Access to both OAM and video RAM, actual pixel transfer to the screen.
};
#endif

95
src/gameboy.cpp
View File

@@ -1,38 +1,6 @@
#include <iostream>
#include "gameboy.hpp"
bool AddressSpace::getBootromState() const {
return bootromLoaded;
}
void AddressSpace::unmapBootrom() {
bootromLoaded = false;
}
void AddressSpace::mapBootrom() {
bootromLoaded = true;
}
void AddressSpace::loadBootrom(const std::string& filename) {
std::ifstream file;
if (const uintmax_t size = std::filesystem::file_size(filename); size != 256) {
std::cerr << "Bootrom was an unexpected size!\nQuitting!\n" << std::endl;
exit(1);
}
file.open(filename, std::ios::binary);
file.read(reinterpret_cast<char*>(bootrom), BOOTROM_SIZE);
}
void AddressSpace::loadGame(const std::string& filename) {
game.open(filename, std::ios::binary);
if (!game.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);
}
void GameBoy::addCycles(const uint8_t ticks) {
cycles += ticks;
if (ppuEnabled) {
@@ -54,43 +22,46 @@ void GameBoy::start(std::string bootrom, std::string game) {
bool display = false;
while (!quit) {
// Event loop: Check and handle SDL events
// Event loop
while (SDL_PollEvent(&event)) {
if (event.type == SDL_QUIT) {
quit = true; // Set the quit flag when the close button is hit
quit = true;
}
}
if (PC > 0xFF && addressSpace.getBootromState()) {
addressSpace.unmapBootrom();
}
ppuEnabled = (*LCDC) & 0x80;
while (!rendered) {
if (PC > 0xFF && addressSpace.getBootromState()) {
addressSpace.unmapBootrom();
}
ppuEnabled = (*LCDC) & 0x80;
// if (PC == 0x100)
// display = true;
// if (display) {
// printf("Cycles: %lu, Opcode: 0x%.2x PPU cycles: %lu, PPMode: %d\n", cycles, addressSpace[PC],
// cyclesSinceLastScanline(), currentMode);
// printf("PC:0x%.2x, SP:0x%.2x\n", PC, SP);
// 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("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("\n");
// }
// if (PC == 0x100)
// display = true;
// if (display) {
// printf("Cycles: %lu, Opcode: 0x%.2x PPU cycles: %lu, PPMode: %d\n", cycles, addressSpace[PC],
// cyclesSinceLastScanline(), currentMode);
// printf("PC:0x%.2x, SP:0x%.2x\n", PC, SP);
// 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("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("\n");
// }
opcodeResolver();
interruptHandler();
timingHandler();
if (ppuEnabled) {
ppuUpdate();
}
else {
ppuCycles = 2;
lastScanline = 0;
lastRefresh = 0;
(*LY) = 0x00;
(*STAT) &= 0xfc;
opcodeResolver();
interruptHandler();
timingHandler();
if (ppuEnabled) {
ppuUpdate();
}
else {
ppuCycles = 2;
lastScanline = 0;
lastRefresh = 0;
(*LY) = 0x00;
(*STAT) &= 0xfc;
}
}
rendered = false;
}
}

79
src/gameboy.hpp
View File

@@ -9,21 +9,7 @@
#include <vector>
#include <SDL.h>
#include "defines.hpp"
//two bits per colour
enum Colour {
black = 0b11,
darkGray = 0b10,
lightGray = 0b01,
white = 0b00
};
enum PPUMode {
mode0, // Horizontal Blank (Mode 0): No access to video RAM, occurs during horizontal blanking period.
mode1, // Vertical Blank (Mode 1): No access to video RAM, occurs during vertical blanking period.
mode2, // OAM Search (Mode 2): Access to OAM (Object Attribute Memory) only, sprite evaluation.
mode3 // Pixel Transfer (Mode 3): Access to both OAM and video RAM, actual pixel transfer to the screen.
};
#include "addressSpace.hpp"
union RegisterPair {
Word reg; //register.reg == (hi << 8) + lo. (hi is more significant than lo)
@@ -34,64 +20,6 @@ union RegisterPair {
};
};
class AddressSpace {
bool bootromLoaded = true;
Byte bootrom[BOOTROM_SIZE] = {0};
std::ifstream game;
public:
AddressSpace() {
// Initialize the memory to zero
memoryLayout = {};
std::memset(memoryLayout.memory, 0, sizeof(memoryLayout.memory));
}
// Nested union for the memory layout
union MemoryLayout {
Byte memory[0x10000];
struct {
Byte romBank1[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
Byte memoryBank1[0x1000]; // Mapped to 0xC000
Byte memoryBank2[0x1000]; // Mapped to 0xD000
Byte echoRam[0x1E00]; // Mapped to 0xE000 (Echo RAM, mirrors 0xC000 to 0xDFFF)
Byte spriteAttributeTable[0xA0]; // Mapped to 0xFE00
Byte notUsable[0x60]; // Mapped to 0xFEA0
Byte io[0x80]; // Mapped to 0xFF00, 0xFF0F is interrupt flag
Byte specialRam[0x7F]; // Mapped to 0xFF80
Byte interuptEnableReg; // Mapped to 0xFFFF
};
} memoryLayout{};
void unmapBootrom();
void mapBootrom();
bool getBootromState() const;
void loadBootrom(const std::string& filename);
void loadGame(const std::string& filename);
//overload [] for echo ram and bootrom support
Byte operator[](const uint32_t address) const {
if (address >= 0xE000 && address < 0xFE00)
return memoryLayout.echoRam[address - 0x2000];
if (address < 0x0100 && bootromLoaded)
return bootrom[address];
return memoryLayout.memory[address];
}
Byte& operator[](const uint32_t address) {
if (address >= 0xE000 && address < 0xFE00)
return memoryLayout.echoRam[address - 0x2000];
if (address < 0x0100 && bootromLoaded)
return bootrom[address];
return memoryLayout.memory[address];
}
};
class GameBoy {
//T-cycles not M-cycles (4 T-cycles = 1 M-cycle)
uint64_t cycles = 0;
@@ -103,6 +31,7 @@ class GameBoy {
uint64_t lastScanline = 0;
uint64_t cyclesToStayInHblank = -1;
uint64_t lastDivUpdate = 0;
bool rendered = false;
uint8_t IME = 0; //enables interupts
@@ -120,7 +49,6 @@ class GameBoy {
//General purpose hardware registers
Byte* const JOYP = &addressSpace[0xFF00];
Byte* const SB = &addressSpace[0xFF01];
Byte* const SC = &addressSpace[0xFF02];
Byte* const DIV = &addressSpace[0xFF04];
@@ -223,6 +151,7 @@ class GameBoy {
//OPCODE FUNCTIONS
template <typename T>
void ld(T& dest, T src);
void ldW(Byte& dest, Word src);
template <typename T>
void orBitwise(T& dest, T src);
template <typename T>
@@ -249,8 +178,6 @@ class GameBoy {
void daa();
void stop();
template <typename T>
void ldW(T dest, T src);
template <typename T>
void cp(T value);
template <typename T>
void dec(T& reg);

1
src/mbc.cpp Normal file
View File

@@ -0,0 +1 @@
#include "gameboy.hpp"

38
src/opcodeResolver.cpp
View File

@@ -46,19 +46,22 @@ void GameBoy::ret() {
template <typename T>
void GameBoy::ld(T& dest, T src) {
if constexpr (std::is_same_v<T, Byte*>) {
if (&dest == DIV)
if constexpr (std::is_same_v<T, Byte>) {
if (&dest == DIV) {
*DIV = 0x00;
lastDivUpdate = cycles;
lastDivUpdate = cycles;
}
else {
dest = src;
}
}
else {
//16-bit register pair write
dest = src;
}
}
template <typename T>
void GameBoy::ldW(T dest, T src) {
void GameBoy::ldW(Byte& dest, const Word src) {
if (sizeof(src) == sizeof(Word)) {
addressSpace[dest] = static_cast<Byte>(src & 0xFF00) >> 8;
addressSpace[dest + 1] = static_cast<Byte>(src & 0xFF);
@@ -169,28 +172,22 @@ void GameBoy::sbc(T value) {
T carry = getFlag(CARRY_FLAG) ? 1 : 0;
T result = AF.hi - value - carry;
if (AF.hi < value + carry) {
if (AF.hi < value + carry)
setFlag(CARRY_FLAG);
}
else {
else
resetFlag(CARRY_FLAG);
}
if (result == 0) {
if (result == 0)
setFlag(ZERO_FLAG);
}
else {
else
resetFlag(ZERO_FLAG);
}
setFlag(SUBTRACT_FLAG);
if ((AF.hi & 0xF) < (value & 0xF) + carry) {
if ((AF.hi & 0xF) < (value & 0xF) + carry)
setFlag(HALFCARRY_FLAG);
}
else {
else
resetFlag(HALFCARRY_FLAG);
}
AF.hi = result;
}
@@ -398,7 +395,6 @@ void GameBoy::dec(T& reg) {
}
void GameBoy::swap(Byte& value) {
// Extract the lower and upper nibbles of the register
const Byte lowerNibble = value & 0x0F;
const Byte upperNibble = (value >> 4) & 0x0F;
@@ -734,7 +730,7 @@ void GameBoy::opcodeResolver() {
break;
case 0x08:
ldW(getWordPC(), SP);
ldW(addressSpace[getWordPC()], SP);
PC += 3;
addCycles(20);
break;
@@ -2237,7 +2233,7 @@ void GameBoy::opcodeResolver() {
break;
case 0xFA:
ldW(AF.hi, addressSpace[getWordPC()]);
ld(AF.hi, addressSpace[getWordPC()]);
PC += 3;
addCycles(16);
break;

5
src/ppu.cpp
View File

@@ -174,7 +174,7 @@ void GameBoy::SDL2setup() {
screen = SDL_CreateWindow("GBpp",
SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
RESOLUTION_X, RESOLUTION_Y,
SDL_WINDOW_OPENGL);
0);
// Create an SDL renderer to draw on the window
renderer = SDL_CreateRenderer(screen, -1, SDL_RENDERER_PRESENTVSYNC | SDL_RENDERER_ACCELERATED);
@@ -203,7 +203,8 @@ void GameBoy::SDL2present() {
if (frameDelay > frameTime) {
SDL_Delay(frameDelay - frameTime);
}
frameStart = SDL_GetTicks();
SDL_RenderPresent(renderer);
frameStart = SDL_GetTicks();
rendered = true;
}