mirror of
https://github.com/FranLMSP/rmg-001.git
synced 2024-09-20 18:20:50 +00:00
240 lines
7.2 KiB
Rust
240 lines
7.2 KiB
Rust
use std::fs::File;
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use std::io::Read;
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use crate::bus::{
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BANK_ZERO,
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BANK_SWITCHABLE,
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EXTERNAL_RAM,
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};
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pub const CARTRIDGE_TYPE_ADDRESS: u16 = 0x0147;
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pub const CGB_FLAG_ADDRESS: u16 = 0x0143;
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pub const SGB_FLAG_ADDRESS: u16 = 0x0146;
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pub const RAM_SIZE_ADDRESS: u16 = 0x0149;
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pub const ROM_SIZE_ADDRESS: u16 = 0x0148;
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pub const DESTINATION_CODE_ADDRESS: u16 = 0x014A;
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enum Region {
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Japanese,
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NonJapanese,
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}
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#[derive(Debug, Copy, Clone)]
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enum MBC {
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NoMBC,
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MBC1,
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MBC2,
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MBC3,
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MBC4,
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MBC5,
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MBC6,
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MBC7,
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HuC1,
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HuC3,
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MMM01,
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MBC1M,
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PocketCamera,
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BandaiTIMA5,
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}
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enum BankingMode {
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Simple,
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Advanced,
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}
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pub struct ROMInfo {
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mbc: MBC,
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publisher: String,
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title: String,
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cgb_only: bool,
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sgb_features: bool,
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has_ram: bool,
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has_battery: bool,
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has_timer: bool,
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ram_banks: u8,
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rom_banks: u16,
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region: Region,
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}
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impl ROMInfo {
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pub fn from_bytes(bytes: &[u8]) -> Self {
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let rom_type = bytes[CARTRIDGE_TYPE_ADDRESS as usize];
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Self {
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mbc: match rom_type {
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0x00 => MBC::NoMBC,
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0x01 => MBC::MBC1,
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0x02 => MBC::MBC1,
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0x03 => MBC::MBC1,
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0x05 => MBC::MBC2,
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0x06 => MBC::MBC2,
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0x08 => MBC::NoMBC,
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0x09 => MBC::NoMBC,
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0x0B => MBC::MMM01,
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0x0C => MBC::MMM01,
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0x0F => MBC::MBC3,
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0x10 => MBC::MBC3,
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0x11 => MBC::MBC3,
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0x12 => MBC::MBC3,
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0x13 => MBC::MBC3,
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0x19 => MBC::MBC5,
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0x1A => MBC::MBC5,
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0x1B => MBC::MBC5,
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0x1C => MBC::MBC5,
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0x1D => MBC::MBC5,
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0x1E => MBC::MBC5,
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0x20 => MBC::MBC6,
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0x22 => MBC::MBC7,
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0xFC => MBC::PocketCamera,
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0xFD => MBC::BandaiTIMA5,
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0xFE => MBC::HuC3,
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0xFF => MBC::HuC1,
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_ => unreachable!(),
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},
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region: match bytes[DESTINATION_CODE_ADDRESS as usize] {
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0x00 => Region::Japanese,
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_ => Region::NonJapanese,
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},
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publisher: "".to_string(), // TODO: Extract publisher
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title: "".to_string(), // TODO: Extract the game title
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cgb_only: bytes[CGB_FLAG_ADDRESS as usize] == 0xC0,
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sgb_features: bytes[SGB_FLAG_ADDRESS as usize] == 0x03,
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has_ram: match rom_type {
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0x02 | 0x03 | 0x08 | 0x09 | 0x0C | 0x0D | 0x10 | 0x12 |
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0x13 | 0x1A | 0x1B | 0x1D | 0x1E | 0x22 | 0xFF => true,
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_ => false,
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},
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has_battery: match rom_type {
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0x03 | 0x06 | 0x09 | 0x0D | 0x0F | 0x10 |
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0x13 | 0x1B | 0x1E | 0x22 | 0xFF => true,
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_ => false,
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},
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has_timer: match rom_type {
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0x0F | 0x10 => true,
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_ => false,
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},
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ram_banks: match bytes[RAM_SIZE_ADDRESS as usize] {
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0x00 | 0x01 => 0,
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0x02 => 1,
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0x03 => 4,
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0x04 => 16,
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0x05 => 8,
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_ => unreachable!(),
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},
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rom_banks: match bytes[ROM_SIZE_ADDRESS as usize] {
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0x00 => 2,
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0x01 => 4,
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0x02 => 8,
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0x03 => 16,
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0x04 => 32,
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0x05 => 64,
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0x06 => 128,
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0x07 => 256,
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0x08 => 512,
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0x52 => 72,
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0x53 => 80,
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0x54 => 96,
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_ => unreachable!(),
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},
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}
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}
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pub fn ram_size(&self) -> usize {
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0x4000 * self.ram_banks as usize
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}
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}
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pub struct ROM {
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data: Vec<u8>,
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info: ROMInfo,
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ram: Vec<u8>,
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rom_bank: u16,
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ram_bank: u8,
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ram_enable: bool,
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banking_mode: BankingMode,
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}
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impl ROM {
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pub fn load_file(filename: String) -> std::io::Result<Self> {
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let mut file = File::open(filename)?;
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let mut data = vec![];
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file.read_to_end(&mut data)?;
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let info = ROMInfo::from_bytes(&data);
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println!("has ram {}", info.has_ram);
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println!("mbc {:?}", info.mbc);
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let ram = Vec::with_capacity(info.ram_size() as usize);
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Ok(Self {
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data,
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info,
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ram,
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rom_bank: 1,
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ram_bank: 0,
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ram_enable: false,
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banking_mode: BankingMode::Simple,
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})
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}
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pub fn read(&self, address: u16) -> u8 {
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match self.info.mbc {
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MBC::MBC1 => {
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if BANK_ZERO.in_range(address) {
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return self.data[address as usize];
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} else if BANK_SWITCHABLE.in_range(address) {
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return self.data[((self.rom_bank as usize * 0x4000) + (address as usize & 0x3FFF)) as usize];
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// return self.data[(address + (BANK_SWITCHABLE.begin() * (self.rom_bank - 1))) as usize];
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} else if EXTERNAL_RAM.in_range(address) {
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println!("RAM read");
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if !self.info.has_ram {
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return 0xFF;
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}
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return self.ram[(address - EXTERNAL_RAM.begin() + (EXTERNAL_RAM.begin() * self.ram_bank as u16)) as usize];
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}
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},
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_ => {},
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}
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self.data[address as usize]
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}
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pub fn write(&mut self, address: u16, data: u8) {
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match self.info.mbc {
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MBC::MBC1 => {
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if address >= 0x0000 && address <= 0x1FFF { // RAM enable register
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self.ram_enable = match data & 0x0F {
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0x0A => true,
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_ => false,
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};
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return;
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} else if address >= 0x2000 && address <= 0x3FFF { // ROM bank number register
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// println!("Switch bank to {:02X}", data);
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self.switch_rom_bank(data as u16 & 0b00011111);
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} else if address >= 0x4000 && address <= 0x5FFF { // ROM and RAM bank number register
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// println!("RAM bank {:02X}", data);
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self.ram_bank = data & 0b11;
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} else if address >= 0x6000 && address <= 0x7FFF { // Banking mode select
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// println!("Change banking mode");
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} else if EXTERNAL_RAM.in_range(address) {
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if !self.ram_enable || !self.info.has_ram {
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return;
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}
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let address = (address - EXTERNAL_RAM.begin() + (EXTERNAL_RAM.begin() * self.ram_bank as u16)) as usize;
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self.ram[address] = data;
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self.switch_rom_bank(self.rom_bank + (data as u16 >> 5));
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}
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},
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_ => {},
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}
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}
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pub fn switch_rom_bank(&mut self, bank: u16) {
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self.rom_bank = bank;
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if self.rom_bank > self.info.rom_banks.saturating_sub(1) {
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self.rom_bank = self.info.rom_banks.saturating_sub(1);
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}
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if self.rom_bank == 0 {
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self.rom_bank = 1;
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}
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}
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}
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