2021-10-14 00:38:37 +00:00
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use crate::rom::ROM;
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2021-10-13 17:56:00 +00:00
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pub enum MemoryMap {
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BankZero,
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BankSwitchable,
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VideoRAM,
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ExternalRAM,
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WorkRAM1,
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WorkRAM2,
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EchoRAM,
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SpriteAttributeTable,
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NotUsable,
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IORegisters,
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HighRAM,
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InterruptEnableRegister,
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}
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impl MemoryMap {
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pub fn get_map(address: u16) -> Self {
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2021-10-14 00:38:37 +00:00
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match address {
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0x0000..=0x3FFF => Self::BankZero,
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0x4000..=0x7FFF => Self::BankSwitchable,
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0x8000..=0x9FFF => Self::VideoRAM,
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0xA000..=0xBFFF => Self::ExternalRAM,
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0xC000..=0xCFFF => Self::WorkRAM1,
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0xD000..=0xDFFF => Self::WorkRAM2,
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0xE000..=0xFDFF => Self::EchoRAM, // Mirror of C000~DDFF
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0xFE00..=0xFE9F => Self::SpriteAttributeTable,
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0xFEA0..=0xFEFF => Self::NotUsable,
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0xFF00..=0xFF7F => Self::IORegisters,
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0xFF80..=0xFFFE => Self::HighRAM,
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0xFFFF => Self::InterruptEnableRegister,
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_ => Self::BankZero,
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}
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}
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}
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pub struct Bus {
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game_rom: ROM,
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2021-10-14 18:25:20 +00:00
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data: [u8; 0x10000],
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2021-10-14 00:38:37 +00:00
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}
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impl Bus {
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pub fn new() -> Self {
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let game_rom = match ROM::load_file("roms/cpu_instrs.gb".to_string()) {
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Ok(rom) => rom,
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_ => ROM::from_bytes(&[0; 0xFFFF])
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};
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game_rom.print_content(Some(0x102));
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Self {
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2021-10-14 18:25:20 +00:00
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data: [0; 0x10000],
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2021-10-14 00:38:37 +00:00
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game_rom,
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}
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}
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pub fn read(&self, address: u16) -> u8 {
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match MemoryMap::get_map(address) {
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MemoryMap::BankZero => self.game_rom.read(address),
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2021-10-14 18:25:20 +00:00
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MemoryMap::BankSwitchable => self.game_rom.read(address),
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MemoryMap::InterruptEnableRegister => self.data[address as usize],
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2021-10-14 00:38:37 +00:00
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_ => self.data[address as usize],
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}
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}
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pub fn write(&mut self, address: u16, data: u8) {
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self.data[address as usize] = data;
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2021-10-13 17:56:00 +00:00
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}
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}
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