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#![allow(dead_code)]
use memory::VMem;
use cartridge::{Cartridge, BankType};
use core::cell::UnsafeCell;
pub struct Mapper2<'a> {
cart: &'a Cartridge,
prg_bank1: UnsafeCell<&'a [u8]>,
prg_bank2: UnsafeCell<&'a [u8]>,
chr_bank: UnsafeCell<&'a mut [u8]>,
sram: UnsafeCell<&'a mut [u8]>,
prg_nbank: usize
}
impl<'a> VMem for Mapper2<'a> {
fn read(&self, addr: u16) -> u8 {
let addr = addr as usize;
unsafe {
if addr < 0x2000 { /* 0x2000 size bank */
(*self.chr_bank.get())[addr]
} else if addr >= 0xc000 { /* 0x4000 size bank */
(*self.prg_bank2.get())[addr - 0xc000]
} else if addr >= 0x8000 { /* 0x4000 size bank */
(*self.prg_bank1.get())[addr - 0x8000]
} else if addr >= 0x6000 {
(*self.sram.get())[addr - 0x6000]
} else {
panic!("unmapped address: 0x{:04x}", addr)
}
}
}
fn write(&self, addr: u16, data: u8) {
let addr = addr as usize;
unsafe {
if addr < 0x2000 {
(*self.chr_bank.get())[addr] = data;
} else if addr >= 0x8000 {
(*self.prg_bank1.get()) =
&*self.cart.get_bank(((data as usize) % self.prg_nbank) << 14,
0x4000,
BankType::PrgRom);
} else if addr >= 0x6000 {
(*self.sram.get())[addr - 0x6000] = data;
} else {
panic!("invalid write to address: 0x{:04x}", addr);
}
}
}
}
impl<'a> Mapper2<'a> {
pub fn new(cart: &'a Cartridge) -> Self {
unsafe {
let nbank = cart.get_size(BankType::PrgRom) >> 14;
Mapper2{cart,
prg_bank1: UnsafeCell::new(&*cart.get_bank(0, 0x4000, BankType::PrgRom)),
prg_bank2: UnsafeCell::new(&*cart.get_bank((nbank - 1) << 14, 0x4000, BankType::PrgRom)),
chr_bank: UnsafeCell::new(&mut *cart.get_bank(0, 0x2000, BankType::ChrRom)),
sram: UnsafeCell::new(&mut *cart.get_bank(0, 0x2000, BankType::Sram)),
prg_nbank: nbank}
}
}
}
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