mirror of
https://github.com/FranLMSP/rmg-001.git
synced 2024-09-20 18:20:50 +00:00
196 lines
7.9 KiB
Rust
196 lines
7.9 KiB
Rust
use crate::utils::{
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get_bit,
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BitIndex,
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join_bytes
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};
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use crate::rom::ROM;
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use crate::ppu::{
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LCD_STATUS_ADDRESS,
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LCD_CONTROL_ADDRESS,
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LCD_Y_ADDRESS,
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DMA_ADDRESS,
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};
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use crate::cpu::{Interrupt};
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use crate::timer::{TIMER_DIVIDER_REGISTER_ADDRESS};
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use crate::joypad::{Joypad, JOYPAD_ADDRESS};
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pub struct AddressRange {
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begin: u16,
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end: u16,
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}
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impl AddressRange {
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pub fn begin(&self) -> u16 {
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self.begin
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}
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pub fn end(&self) -> u16 {
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self.end
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}
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pub fn in_range(&self, address: u16) -> bool {
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address >= self.begin && address <= self.end
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}
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}
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pub const BANK_ZERO: AddressRange = AddressRange{begin: 0x0000, end: 0x3FFF};
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pub const BANK_SWITCHABLE: AddressRange = AddressRange{begin: 0x4000, end: 0x7FFF};
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pub const VIDEO_RAM: AddressRange = AddressRange{begin: 0x8000, end: 0x9FFF};
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pub const EXTERNAL_RAM: AddressRange = AddressRange{begin: 0xA000, end: 0xBFFF};
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pub const WORK_RAM_1: AddressRange = AddressRange{begin: 0xC000, end: 0xCFFF};
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pub const WORK_RAM_2: AddressRange = AddressRange{begin: 0xD000, end: 0xDFFF};
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pub const ECHO_RAM: AddressRange = AddressRange{begin: 0xE000, end: 0xFDFF};
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pub const SPRITE_ATTRIBUTE_TABLE: AddressRange = AddressRange{begin: 0xFE00, end: 0xFE9F};
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pub const NOT_USABLE: AddressRange = AddressRange{begin: 0xFEA0, end: 0xFEFF};
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pub const IO_REGISTERS: AddressRange = AddressRange{begin: 0xFF00, end: 0xFF7F};
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pub const HIGH_RAM: AddressRange = AddressRange{begin: 0xFF80, end: 0xFFFE};
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pub const INTERRUPT_ENABLE_REGISTER: AddressRange = AddressRange{begin: 0xFFFF, end: 0xFFFF};
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pub const INTERRUPT_ENABLE_ADDRESS: u16 = 0xFFFF;
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pub const INTERRUPT_FLAG_ADDRESS: u16 = 0xFF0F;
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pub struct Bus {
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game_rom: ROM,
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data: [u8; 0x10000],
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pub reset_timer: bool,
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pub joypad: Joypad,
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}
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impl Bus {
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pub fn new() -> Self {
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let game_rom = match ROM::load_file("ignore/tetris.gb".to_string()) {
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// let game_rom = match ROM::load_file("roms/cpu_instrs.gb".to_string()) {
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// let game_rom = match ROM::load_file("roms/cpu_instrs_individual/01-special.gb".to_string()) {
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// let game_rom = match ROM::load_file("roms/cpu_instrs_individual/02-interrupts.gb".to_string()) {
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// let game_rom = match ROM::load_file("roms/cpu_instrs_individual/03-op sp,hl.gb".to_string()) {
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// let game_rom = match ROM::load_file("roms/cpu_instrs_individual/04-op r,imm.gb".to_string()) {
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// let game_rom = match ROM::load_file("roms/cpu_instrs_individual/05-op rp.gb".to_string()) {
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// let game_rom = match ROM::load_file("roms/cpu_instrs_individual/06-ld r,r.gb".to_string()) {
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// let game_rom = match ROM::load_file("roms/cpu_instrs_individual/07-jr,jp,call,ret,rst.gb".to_string()) {
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// let game_rom = match ROM::load_file("roms/cpu_instrs_individual/08-misc instrs.gb".to_string()) {
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// let game_rom = match ROM::load_file("roms/cpu_instrs_individual/09-op r,r.gb".to_string()) {
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// let game_rom = match ROM::load_file("roms/cpu_instrs_individual/10-bit ops.gb".to_string()) {
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// let game_rom = match ROM::load_file("roms/cpu_instrs_individual/11-op a,(hl).gb".to_string()) {
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Ok(rom) => rom,
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// _ => ROM::from_bytes(&[0; 0xFFFF])
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_ => panic!("Could not read ROM"),
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};
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let mut data = [0x00; 0x10000];
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// Hardware registers after the bootrom
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data[0xFF00] = 0xCF;
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data[0xFF01] = 0x00;
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data[0xFF02] = 0x7E;
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data[0xFF04] = 0x18;
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data[0xFF05] = 0x00;
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data[0xFF06] = 0x00;
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data[0xFF07] = 0xF8;
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data[0xFF0F] = 0xE1;
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data[0xFF40] = 0x91;
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data[0xFF41] = 0x81;
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data[0xFF42] = 0x00;
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data[0xFF43] = 0x00;
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data[0xFF44] = 0x91;
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data[0xFF45] = 0x00;
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data[0xFF46] = 0xFF;
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data[0xFF47] = 0xFC;
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data[0xFF4A] = 0x00;
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data[0xFF4B] = 0x00;
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data[0xFFFF] = 0x00;
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Self {
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data,
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game_rom,
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reset_timer: false,
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joypad: Joypad::new(),
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}
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}
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pub fn read(&self, address: u16) -> u8 {
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if BANK_ZERO.in_range(address) || BANK_SWITCHABLE.in_range(address) {
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return self.game_rom.read(address);
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} else if address == INTERRUPT_ENABLE_ADDRESS || address == INTERRUPT_FLAG_ADDRESS {
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return 0b11100000 | self.data[address as usize];
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} else if address == JOYPAD_ADDRESS {
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return self.joypad.read(self.data[address as usize]);
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}
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self.data[address as usize]
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}
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pub fn read_16bit(&self, address: u16) -> u16 {
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join_bytes(self.read(address.wrapping_add(1)), self.read(address))
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}
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pub fn write(&mut self, address: u16, data: u8) {
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if address == 0xFF01 {
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// print!("{}", data as char);
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}
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if BANK_ZERO.in_range(address) || BANK_SWITCHABLE.in_range(address) {
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// println!("WRITING TO ROM");
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} else if WORK_RAM_1.in_range(address) || WORK_RAM_2.in_range(address) {
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self.data[address as usize] = data;
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// Copy to the ECHO RAM
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if address <= 0xDDFF {
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self.data[(ECHO_RAM.begin() + (address - WORK_RAM_1.begin())) as usize] = data;
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}
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} else if EXTERNAL_RAM.in_range(address) {
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// self.game_rom.write(address, data);
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} else if ECHO_RAM.in_range(address) {
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self.data[address as usize] = data;
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self.data[(WORK_RAM_1.begin() + (address - ECHO_RAM.begin())) as usize] = data; // Copy to the working RAM
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} else if address == TIMER_DIVIDER_REGISTER_ADDRESS {
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self.reset_timer = true;
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} else if address == LCD_CONTROL_ADDRESS && get_bit(data, BitIndex::I7) {
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self.data[address as usize] = data;
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self.data[LCD_Y_ADDRESS as usize] = 0x00;
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} else if address == LCD_Y_ADDRESS {
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// println!("Write to LCD_Y not allowed");
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} else if address == LCD_STATUS_ADDRESS {
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let byte = self.data[address as usize];
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self.data[address as usize] = (data & 0b11111000) | (byte & 0b00000111);
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} else if address == JOYPAD_ADDRESS {
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let byte = self.data[address as usize];
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self.data[address as usize] = (data & 0b11110000) | (byte & 0b00001111);
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} else if address == DMA_ADDRESS {
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// the idea is: when something gets written to $FF46, multiply it by 0x100, then copy 160 bytes starting from that memory location into OAM
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self.data[address as usize] = data;
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let source = (data as usize) * 0x100;
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let mut count = 0;
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let oam_addr = SPRITE_ATTRIBUTE_TABLE.begin() as usize;
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while count < 160 {
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self.data[oam_addr + count] = self.data[source + count];
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count += 1;
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}
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} else {
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self.data[address as usize] = data;
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}
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}
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pub fn force_write(&mut self, address: u16, data: u8) {
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self.data[address as usize] = data;
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}
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pub fn write_16bit(&mut self, address: u16, data: u16) {
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let bytes = data.to_le_bytes();
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self.write(address, bytes[0]);
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self.write(address.wrapping_add(1), bytes[1]);
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}
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pub fn set_interrupt_enable(&mut self, interrupt: Interrupt, val: bool) {
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let byte = self.read(INTERRUPT_ENABLE_ADDRESS);
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self.write(INTERRUPT_ENABLE_ADDRESS, interrupt.set(byte, val));
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}
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pub fn set_interrupt_flag(&mut self, interrupt: Interrupt, val: bool) {
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let byte = self.read(INTERRUPT_FLAG_ADDRESS);
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self.write(INTERRUPT_FLAG_ADDRESS, interrupt.set(byte, val));
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}
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pub fn get_interrupt(&mut self, interrupt: Interrupt) -> bool {
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let byte = self.read(INTERRUPT_ENABLE_ADDRESS) & self.read(INTERRUPT_FLAG_ADDRESS);
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interrupt.get(byte)
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}
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}
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