76 lines
2.0 KiB
Rust
76 lines
2.0 KiB
Rust
use super::{serialize::*, Cartridge, Mapper, Mirror};
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pub struct Nrom {
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cart: Cartridge,
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chr_ram: Vec<u8>,
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}
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impl Nrom {
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pub fn new(cart: Cartridge) -> Self {
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Nrom {
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cart: cart,
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chr_ram: vec![0; 0x2000],
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}
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}
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}
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impl Mapper for Nrom {
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fn read(&self, address: usize) -> u8 {
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let addr = address % 0x4000;
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match address {
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0x0000..=0x1FFF => {
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if self.cart.chr_rom_size > 0 {
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self.cart.chr_rom[0][address]
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} else {
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self.chr_ram[address]
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}
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}
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0x8000..=0xBFFF => self.cart.prg_rom[0][addr],
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0xC000..=0xFFFF => self.cart.prg_rom[self.cart.prg_rom_size - 1][addr],
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_ => {
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println!("bad address read from NROM mapper: 0x{:X}", address);
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0
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}
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}
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}
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fn write(&mut self, address: usize, value: u8) {
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match address {
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0x0000..=0x1FFF => {
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// ROM isn't written to
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if self.cart.chr_rom_size == 0 {
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self.chr_ram[address] = value;
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}
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}
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0x8000..=0xBFFF => (),
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0xC000..=0xFFFF => (),
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_ => println!("bad address written to NROM mapper: 0x{:X}", address),
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}
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}
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fn get_mirroring(&self) -> Mirror {
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self.cart.mirroring
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}
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fn load_battery_backed_ram(&mut self) {}
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fn save_battery_backed_ram(&self) {}
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fn clock(&mut self) {}
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fn check_irq(&mut self) -> bool {
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false
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}
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fn save_state(&self) -> MapperData {
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MapperData::Nrom(NromData {
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cart: self.cart.clone(),
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chr_ram: self.chr_ram.clone(),
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})
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}
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fn load_state(&mut self, mapper_data: MapperData) {
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if let MapperData::Nrom(nrom_data) = mapper_data {
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self.cart = nrom_data.cart;
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self.chr_ram = nrom_data.chr_ram;
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}
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}
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}
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