YayIguess/GBpp
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more mbc work

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This commit is contained in:
Braiden Gent
2024-03-31 02:47:57 -07:00
parent 0bcf339ebf
commit 0f95c0da86
5 changed files with 90 additions and 22 deletions
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19
src/addressSpace.cpp
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@@ -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);
}

22
src/addressSpace.hpp
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@@ -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 RomPages = 0;
uint32_t ExternalRamSize = 0;
uint32_t ExternalRamPages = 0;
uint32_t romSize = 0;
uint32_t romBanks = 0;
uint32_t externalRamSize = 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 {

26
src/gameboy.cpp
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@@ -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)
// 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 >= 0xe0)
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("Cart type: 0x%.2x\n", addressSpace.game[0x147]);
printf("\n");
}
opcodeResolver();
interruptHandler();

2
src/gameboy.hpp
View File

@@ -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();

43
src/mbc.cpp
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@@ -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;
}