121 lines
3.6 KiB
Rust
121 lines
3.6 KiB
Rust
use crate::nes::ppu::PPU;
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use std::rc::Rc;
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use core::cell::RefCell;
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use crate::nes::cartridge::Cartridge;
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use crate::nes::types::*;
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pub const RAM_SIZE: usize = 0x0800;
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pub const RAM_ADDR_RANGE: [Addr; 2] = [0x0000, 0x1fff];
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pub const RAM_PHYS_RANGE: [Addr; 2] = [0x0000, 0x07ff];
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pub const PPU_ADDR_RANGE: [Addr; 2] = [0x2000, 0x3fff];
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pub const PPU_PHYS_RANGE: [Addr; 2] = [0x2000, 0x2007];
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pub const CART_ADDR_RANGE: [Addr; 2] = [0x4020, 0xffff];
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// NES memory: Contains data from RAM, cartridge...
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pub struct NESMemory {
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ram: [Byte; RAM_SIZE], // 2kb
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cartridge: Option<Cartridge>,
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ppu: Rc<RefCell<PPU>>,
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}
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impl NESMemory {
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pub fn new(ppu: Rc<RefCell<PPU>>) -> Self {
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NESMemory {
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ram: [0; RAM_SIZE],
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cartridge: None,
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ppu: ppu,
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}
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}
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pub fn insert_cartridge(&mut self, c: Cartridge) {
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self.cartridge = Some(c);
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}
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}
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pub trait Memory {
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fn readb(&self, addr: Addr) -> Byte;
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fn writeb(&mut self, addr: Addr, data: Byte);
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fn readw(&self, addr: Addr) -> Word {
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let lo = self.readb(addr);
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let hi = self.readb(addr+1);
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(hi as Word) << 8 | lo as Word
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}
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fn writew(&mut self, addr: Addr, data: Word) {
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self.writeb(addr, data as Byte);
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self.writeb(addr + 1, (data >> 8) as Byte);
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}
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}
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impl Memory for NESMemory {
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fn readb(&self, addr: Addr) -> Byte {
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if let Some(cartridge) = &self.cartridge {
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if CART_ADDR_RANGE[0] <= addr && addr <= CART_ADDR_RANGE[1] {
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return cartridge.readb(addr)
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}
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}
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if RAM_ADDR_RANGE[0] <= addr && addr <= RAM_ADDR_RANGE[1] {
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// Ram is 3x mirrored after 0x07ff
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return self.ram[(addr & RAM_PHYS_RANGE[1]) as usize]
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}
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if PPU_ADDR_RANGE[0] <= addr && addr <= PPU_ADDR_RANGE[1] {
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let ppu = self.ppu.borrow();
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return ppu.readb(addr & PPU_PHYS_RANGE[1]);
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}
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0x0000 // generic response
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}
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fn writeb(&mut self, addr: Addr, data: Byte) {
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if let Some(cartridge) = &mut self.cartridge {
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if CART_ADDR_RANGE[0] <= addr && addr <= CART_ADDR_RANGE[1] {
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cartridge.writeb(addr, data)
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}
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}
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if RAM_ADDR_RANGE[0] <= addr && addr <= RAM_ADDR_RANGE[1] {
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// Ram is 3x mirrored after 07ff
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self.ram[(addr & RAM_PHYS_RANGE[1]) as usize] = data
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}
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if PPU_ADDR_RANGE[0] <= addr && addr <= PPU_ADDR_RANGE[1] {
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let mut ppu = self.ppu.borrow_mut();
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ppu.writeb(addr & PPU_PHYS_RANGE[1], data);
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}
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}
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}
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pub trait MemoryReader {
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fn readb<T: Memory>(&self, mem: &T, addr: Addr) -> Byte {
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mem.readb(addr)
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}
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fn readw<T: Memory>(&self, mem: &T, addr: Addr) -> Word {
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mem.readw(addr)
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}
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fn writeb<T: Memory>(&mut self, mem: &mut T, addr: Addr, data: Byte) {
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mem.writeb(addr, data)
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}
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}
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// PPU interface to allow read/write of memory
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pub trait PPUMemory {
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fn readb_ppu(&self, addr: Addr) -> Byte;
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fn writeb_ppu(&mut self, addr: Addr, data: Byte);
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fn readw_ppu(&self, addr: Addr) -> Word {
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let lo = self.readb_ppu(addr);
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let hi = self.readb_ppu(addr+1);
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(hi as Word) << 8 | lo as Word
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}
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fn writew_ppu(&mut self, addr: Addr, data: Word) {
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self.writeb_ppu(addr, data as Byte);
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self.writeb_ppu(addr + 1, (data >> 8) as Byte);
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}
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}
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pub trait PPUMemoryReader {
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fn readb_ppu<T: PPUMemory>(&self, mem: &T, addr: Addr) -> Byte {
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mem.readb_ppu(addr)
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}
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fn writeb_ppu<T: PPUMemory>(&mut self, mem: &mut T, addr: Addr, data: Byte) {
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mem.writeb_ppu(addr, data)
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}
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} |