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use memory::VMem;
use cartridge::{Cartridge, BankType};
pub struct Mapper2<'a, T: 'a> where T: Cartridge {
cart: &'a T,
prg_bank1: &'a [u8],
prg_bank2: &'a [u8],
chr_bank: &'a mut [u8],
sram: &'a mut [u8],
bank_num: usize
}
impl<'a, T> VMem for Mapper2<'a, T> where T: Cartridge {
fn read(&self, addr: u16) -> u8 {
let addr = addr as usize;
if addr < 0x2000 {
self.chr_bank[addr]
} else if addr >= 0xc000 {
self.prg_bank2[addr - 0xc000]
} else if addr >= 0x8000 {
self.prg_bank1[addr - 0x8000]
} else if addr >= 0x6000 {
self.sram[addr - 0x6000]
} else {
panic!("unmapped address: 0x{:04x}", addr)
}
}
fn write(&mut self, addr: u16, data: u8) {
let addr = addr as usize;
if addr < 0x2000 {
self.chr_bank[addr] = data;
} else if addr >= 0x8000 {
self.prg_bank1 = unsafe {&*self.cart.get_bank(
data as usize % self.bank_num, BankType::PRG_ROM)};
} else if addr >= 0x6000 {
self.sram[addr - 0x6000] = data;
} else {
panic!("invalid write to address: 0x{:04x}", addr);
}
}
}
impl<'a, T> Mapper2<'a, T> where T: Cartridge {
fn new(cart: &'a mut T) -> Self {
let bank_num = cart.get_bank_num(BankType::PRG_ROM);
unsafe {
Mapper2{cart,
prg_bank1: &*cart.get_bank(0, BankType::PRG_ROM),
prg_bank2: &*cart.get_bank(bank_num - 1, BankType::PRG_ROM),
chr_bank: &mut *cart.get_bank(0, BankType::CHR_ROM),
sram: &mut *cart.get_bank(0, BankType::SRAM),
bank_num}
}
}
}
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