chore: better structure for boot loading of CGB

frontends/sdl/src/main.rs

@@ -7,7 +7,7 @@ pub mod graphics;
 use audio::Audio;
 use boytacean::{
     devices::printer::PrinterDevice,
-    gb::{AudioProvider, GameBoy},
+    gb::{AudioProvider, GBMode, GameBoy},
     pad::PadKey,
     ppu::{PaletteInfo, PpuMode, DISPLAY_HEIGHT, DISPLAY_WIDTH},
 };
@@ -186,7 +186,7 @@ impl Emulator {
 
     pub fn reset(&mut self) {
         self.system.reset();
-        self.system.load_boot_default();
+        self.system.load(true);
         self.load_rom(None);
     }
 
@@ -317,7 +317,7 @@ impl Emulator {
                     }
                     Event::DropFile { filename, .. } => {
                         self.system.reset();
-                        self.system.load_boot_cgb();
+                        self.system.load(true);
                         self.load_rom(Some(&filename));
                     }
                     _ => (),
@@ -446,7 +446,7 @@ impl Emulator {
 fn main() {
     // creates a new Game Boy instance and loads both the boot ROM
     // and the initial game ROM to "start the engine"
-    let mut game_boy = GameBoy::new();
+    let mut game_boy = GameBoy::new(GBMode::Cgb);
     let mut printer = Box::<PrinterDevice>::default();
     printer.set_callback(|image_buffer| {
         let file_name = format!("printer-{}.png", Utc::now().format("%Y%m%d-%H%M%S"));
@@ -460,7 +460,7 @@ fn main() {
         .unwrap();
     });
     game_boy.attach_serial(printer);
-    game_boy.load_boot_cgb();
+    game_boy.load(true);
 
     // creates a new generic emulator structure then starts
     // both the video and audio sub-systems, loads default

src/gb.rs

@@ -30,11 +30,24 @@ use std::{
     panic::{set_hook, take_hook, PanicInfo},
 };
 
+/// Enumeration that describes the multiple running
+// modes of the Game Boy emulator.
+pub enum GBMode {
+    Dmg = 1,
+    Cgb = 2,
+    Sgb = 3,
+}
+
 /// Top level structure that abstracts the usage of the
 /// Game Boy system under the Boytacean emulator.
 /// Should serve as the main entry-point API.
 #[cfg_attr(feature = "wasm", wasm_bindgen)]
 pub struct GameBoy {
+    /// The current running mode of the emulator, this
+    /// may affect many aspects of the emulation, like
+    /// CPU frequency, PPU frequency, Boot rome size, etc.
+    mode: GBMode,
+
     /// Reference to the Game Boy CPU component to be
     /// used as the main element of the system, when
     /// clocked, the amount of ticks from it will be
@@ -90,7 +103,7 @@ pub trait AudioProvider {
 #[cfg_attr(feature = "wasm", wasm_bindgen)]
 impl GameBoy {
     #[cfg_attr(feature = "wasm", wasm_bindgen(constructor))]
-    pub fn new() -> Self {
+    pub fn new(mode: GBMode) -> Self {
         let ppu = Ppu::default();
         let apu = Apu::default();
         let pad = Pad::default();
@@ -99,6 +112,7 @@ impl GameBoy {
         let mmu = Mmu::new(ppu, apu, pad, timer, serial);
         let cpu = Cpu::new(mmu);
         Self {
+            mode,
             cpu,
             ppu_enabled: true,
             apu_enabled: true,
@@ -178,10 +192,11 @@ impl GameBoy {
         self.cpu.boot();
     }
 
-    pub fn load_default(&mut self, boot: bool) {
-        self.mmu().allocate_default();
-        if boot {
-            self.load_boot_default();
+    pub fn load(&mut self, boot: bool) {
+        match self.mode {
+            GBMode::Dmg => self.load_dmg(boot),
+            GBMode::Cgb => self.load_cgb(boot),
+            GBMode::Sgb => todo!(),
         }
     }
 
@@ -601,6 +616,6 @@ impl AudioProvider for GameBoy {
 
 impl Default for GameBoy {
     fn default() -> Self {
-        Self::new()
+        Self::new(GBMode::Dmg)
     }
 }