gb-emu/src/processor/memory/rom/mbcs.rs

use crate::processor::memory::Address;

mod mbc1;
mod mbc5;
mod none;
pub use mbc1::Mbc1;
pub use mbc5::Mbc5;
pub use none::None;

const KB: usize = 1024;
const ROM_BANK_SIZE: usize = 16 * KB;
const RAM_BANK_SIZE: usize = 8 * KB;

pub(super) trait Mbc {
    // addresses 0x0000 - 0x7FFF
    fn get(&self, address: Address) -> u8;
    // addresses 0xA000 - 0xBFFF
    fn get_ram(&self, address: Address) -> u8;
    fn set(&mut self, address: Address, data: u8);
    fn set_ram(&mut self, address: Address, data: u8);
    fn mbc_type(&self) -> String;
}

fn rom_banks(rom_size: u8) -> usize {
    match rom_size {
        0x00 => 2,
        0x01 => 4,
        0x02 => 8,
        0x03 => 16,
        0x04 => 32,
        0x05 => 64,
        0x06 => 128,
        0x07 => 256,
        0x08 => 512,
        0x52 => 72,
        0x53 => 80,
        0x54 => 96,
        _ => panic!("unacceptable rom size"),
    }
}

fn ram_size_kb(ram_size: u8) -> Option<usize> {
    match ram_size {
        0x00 => None,
        0x01 => Some(2),
        0x02 => Some(8),
        0x03 => Some(32),
        0x04 => Some(128),
        0x05 => Some(64),
        _ => panic!("unacceptable ram size"),
    }
}