add SyncUnsafeCell implementation

agb/src/lib.rs

@@ -190,6 +190,7 @@ mod sync;
 pub mod syscall;
 /// Interactions with the internal timers
 pub mod timer;
+pub(crate) mod util;
 
 mod no_game;
 

agb/src/util.rs

@@ -0,0 +1,16 @@
+use core::cell::UnsafeCell;
+
+pub struct SyncUnsafeCell<T>(UnsafeCell<T>);
+
+unsafe impl<T> Sync for SyncUnsafeCell<T> {}
+unsafe impl<T> Send for SyncUnsafeCell<T> {}
+
+impl<T> SyncUnsafeCell<T> {
+    pub const fn new(t: T) -> Self {
+        Self(UnsafeCell::new(t))
+    }
+
+    pub unsafe fn get(&self) -> *mut T {
+        self.0.get()
+    }
+}