feat: initial loading of information

src/chip8_neo.rs

@@ -8,6 +8,25 @@ pub const REGISTERS_SIZE: usize = 16;
 /// the initial PC position.
 const ROM_START: usize = 0x200;
 
+static FONT_SET: [u8; 80] = [
+    0xf0, 0x90, 0x90, 0x90, 0xf0, // 0
+    0x20, 0x60, 0x20, 0x20, 0x70, // 1
+    0xf0, 0x10, 0xf0, 0x80, 0xf0, // 2
+    0xf0, 0x10, 0xf0, 0x10, 0xf0, // 3
+    0x90, 0x90, 0xf0, 0x10, 0x10, // 4
+    0xf0, 0x80, 0xf0, 0x10, 0xf0, // 5
+    0xf0, 0x80, 0xf0, 0x90, 0xf0, // 6
+    0xf0, 0x10, 0x20, 0x40, 0x40, // 7
+    0xf0, 0x90, 0xf0, 0x90, 0xf0, // 8
+    0xf0, 0x90, 0xf0, 0x10, 0xf0, // 9
+    0xf0, 0x90, 0xf0, 0x90, 0x90, // A
+    0xe0, 0x90, 0xe0, 0x90, 0xe0, // B
+    0xf0, 0x80, 0x80, 0x80, 0xf0, // C
+    0xe0, 0x90, 0x90, 0x90, 0xe0, // D
+    0xf0, 0x80, 0xf0, 0x80, 0xf0, // E
+    0xf0, 0x80, 0xf0, 0x80, 0x80, // F
+];
+
 pub struct Chip8Neo {
     ram: [u8; RAM_SIZE],
     vram: [u8; DISPLAY_WIDTH * DISPLAY_HEIGHT],
@@ -24,7 +43,7 @@ pub struct Chip8Neo {
 impl Chip8Neo {
     #[cfg_attr(feature = "web", wasm_bindgen(constructor))]
     pub fn new() -> Chip8Neo {
-        let chip8 = Chip8Neo {
+        let mut chip8 = Chip8Neo {
             ram: [0u8; RAM_SIZE],
             vram: [0u8; DISPLAY_WIDTH * DISPLAY_HEIGHT],
             stack: [0u16; STACK_SIZE],
@@ -35,10 +54,23 @@ impl Chip8Neo {
             dt: 0x0,
             st: 0x0,
         };
+        chip8.load_default_font();
         chip8
     }
 
     pub fn tick(&mut self) {
         self.pc += 0x2;
     }
+
+    pub fn load_rom(&mut self, rom: &[u8]) {
+        self.ram[ROM_START..ROM_START + rom.len()].clone_from_slice(&rom);
+    }
+
+    fn load_font(&mut self, position: usize, font_set: &[u8]) {
+        self.ram[position..position + font_set.len()].clone_from_slice(&font_set);
+    }
+
+    fn load_default_font(&mut self) {
+        self.load_font(0, &FONT_SET);
+    }
 }