add bitarray implementation

agb/src/bitarray.rs

@@ -0,0 +1,24 @@
+pub struct Bitarray<const N: usize> {
+    a: [u32; N],
+}
+
+impl<const N: usize> Bitarray<N> {
+    pub fn new() -> Self {
+        Bitarray { a: [0; N] }
+    }
+
+    pub fn get(&self, index: usize) -> Option<bool> {
+        if index < N * 32 {
+            Some((self.a[index / N] >> (N % 32) & 1) != 0)
+        } else {
+            None
+        }
+    }
+
+    pub fn set(&mut self, index: usize, value: bool) {
+        let value = value as u32;
+        let mask = 1 << (N % 32);
+        let value_mask = value << (N % 32);
+        self.a[index / N] = self.a[index / N] & !mask | value_mask
+    }
+}

agb/src/lib.rs

@@ -20,6 +20,7 @@ pub mod input;
 /// Implements sound output.
 pub mod sound;
 
+mod bitarray;
 mod interrupt;
 mod memory_mapped;
 /// Implements logging to the mgba emulator.