1 files changed, 24 insertions, 0 deletions
diff --git a/src/mapper.rs b/src/mapper.rs
index cf946a2..446d5b9 100644
--- a/src/mapper.rs
+++ b/src/mapper.rs
@@ -1,5 +1,6 @@
 #![allow(dead_code)]
 extern crate core;
+use core::cell::UnsafeCell;
 use memory::{VMem, CPUBus};
 use cartridge::{Cartridge, BankType, MirrorType};
 
@@ -8,6 +9,29 @@ pub trait Mapper : VMem {
     fn tick(&mut self, _bus: &CPUBus) {}
 }
 
+pub struct RefMapper<'a> {
+    mapper: UnsafeCell<&'a mut Mapper>
+}
+
+impl<'a> RefMapper<'a> {
+    pub fn new(mapper: &'a mut Mapper) -> Self {
+        RefMapper { mapper: UnsafeCell::new(mapper) }
+    }
+
+    #[inline(always)]
+    pub fn get_mut(&self) -> &'a mut Mapper {
+        unsafe { *self.mapper.get() }
+    }
+}
+
+impl<'a> core::ops::Deref for RefMapper<'a> {
+    type Target = &'a mut Mapper;
+    #[inline(always)]
+    fn deref(&self) -> &&'a mut Mapper {
+        unsafe { &*self.mapper.get() }
+    }
+}
+
 pub struct Mapper1<'a, C> where C: Cartridge {
     cart: C,
     prg_banks: [&'a [u8]; 2],