diff --git a/src/mem.rs b/src/mem.rs
index 5959f10..bbaaf38 100644
--- a/src/mem.rs
+++ b/src/mem.rs
@@ -19,10 +19,11 @@ pub struct MemConfig {
 }
 
 impl MemConfig {
-    pub fn find_device_by_page(&self, page: PageNum) -> Option<Arc<dyn MemDeviceInterface>> {
+    #[allow(clippy::needless_borrow)]
+    pub fn find_device_by_page(&self, page: PageNum) -> Option<&DeviceEntry> {
         for entry in self.devices.iter() {
             if page_in_range(page, entry.base, entry.size) {
-                return Some(entry.interface.clone());
+                return Some(&entry);
             }
         }
 
@@ -31,11 +32,134 @@ impl MemConfig {
 
     pub fn read_dword(&self, page: PageNum, offset: u16) -> Result<DWord, MemAccessFault> {
         if page_in_range(page, self.ram_start, self.ram.pages) {
-            self.ram.read_dword(page, offset)
+            self.ram.read_dword(page - self.ram_start, offset)
         } else {
-            self.find_device_by_page(page)
-                .ok_or(MemAccessFault)?
-                .read_dword(page, offset)
+            let entry = self.find_device_by_page(page).ok_or(MemAccessFault)?;
+
+            entry.interface.read_dword(page - entry.base, offset)
+        }
+    }
+    pub fn read_word(&self, page: PageNum, offset: u16) -> Result<Word, MemAccessFault> {
+        if page_in_range(page, self.ram_start, self.ram.pages) {
+            self.ram.read_word(page - self.ram_start, offset)
+        } else {
+            let entry = self.find_device_by_page(page).ok_or(MemAccessFault)?;
+
+            entry.interface.read_word(page - entry.base, offset)
+        }
+    }
+    pub fn read_hword(&self, page: PageNum, offset: u16) -> Result<HWord, MemAccessFault> {
+        if page_in_range(page, self.ram_start, self.ram.pages) {
+            self.ram.read_hword(page - self.ram_start, offset)
+        } else {
+            let entry = self.find_device_by_page(page).ok_or(MemAccessFault)?;
+
+            entry.interface.read_hword(page - entry.base, offset)
+        }
+    }
+    pub fn read_byte(&self, page: PageNum, offset: u16) -> Result<Byte, MemAccessFault> {
+        if page_in_range(page, self.ram_start, self.ram.pages) {
+            self.ram.read_byte(page - self.ram_start, offset)
+        } else {
+            let entry = self.find_device_by_page(page).ok_or(MemAccessFault)?;
+
+            entry.interface.read_byte(page - entry.base, offset)
+        }
+    }
+
+    pub fn write_dword(
+        &self,
+        page: PageNum,
+        offset: u16,
+        value: DWord,
+    ) -> Result<(), MemAccessFault> {
+        if page_in_range(page, self.ram_start, self.ram.pages) {
+            self.ram.write_dword(page - self.ram_start, offset, value)
+        } else {
+            let entry = self.find_device_by_page(page).ok_or(MemAccessFault)?;
+            entry
+                .interface
+                .write_dword(page - entry.base, offset, value)
+        }
+    }
+    pub fn write_word(
+        &self,
+        page: PageNum,
+        offset: u16,
+        value: Word,
+    ) -> Result<(), MemAccessFault> {
+        if page_in_range(page, self.ram_start, self.ram.pages) {
+            self.ram.write_word(page - self.ram_start, offset, value)
+        } else {
+            let entry = self.find_device_by_page(page).ok_or(MemAccessFault)?;
+            entry.interface.write_word(page - entry.base, offset, value)
+        }
+    }
+    pub fn write_hword(
+        &self,
+        page: PageNum,
+        offset: u16,
+        value: HWord,
+    ) -> Result<(), MemAccessFault> {
+        if page_in_range(page, self.ram_start, self.ram.pages) {
+            self.ram.write_hword(page - self.ram_start, offset, value)
+        } else {
+            let entry = self.find_device_by_page(page).ok_or(MemAccessFault)?;
+            entry
+                .interface
+                .write_hword(page - entry.base, offset, value)
+        }
+    }
+    pub fn write_byte(
+        &self,
+        page: PageNum,
+        offset: u16,
+        value: Byte,
+    ) -> Result<(), MemAccessFault> {
+        if page_in_range(page, self.ram_start, self.ram.pages) {
+            self.ram.write_byte(page - self.ram_start, offset, value)
+        } else {
+            let entry = self.find_device_by_page(page).ok_or(MemAccessFault)?;
+            entry.interface.write_byte(page - entry.base, offset, value)
+        }
+    }
+
+    pub fn get_atomic_dword(
+        &self,
+        page: PageNum,
+        offset: u16,
+    ) -> Result<&AtomicU64, MemAccessFault> {
+        if page_in_range(page, self.ram_start, self.ram.pages) {
+            debug_assert!(((offset * 8) as usize) < PAGE_SIZE);
+            let index = page * (PAGE_SIZE / 8) + (offset as usize);
+            unsafe {
+                self.ram
+                    .buf_transmuted::<AtomicU64>()
+                    .get(index)
+                    .ok_or(MemAccessFault)
+            }
+        } else {
+            let entry = self.find_device_by_page(page).ok_or(MemAccessFault)?;
+            entry.interface.get_atomic_dword(page - entry.base, offset)
+        }
+    }
+    pub fn get_atomic_word(
+        &self,
+        page: PageNum,
+        offset: u16,
+    ) -> Result<&AtomicU32, MemAccessFault> {
+        if page_in_range(page, self.ram_start, self.ram.pages) {
+            debug_assert!(((offset * 4) as usize) < PAGE_SIZE);
+            let index = page * (PAGE_SIZE / 4) + (offset as usize);
+            unsafe {
+                self.ram
+                    .buf_transmuted::<AtomicU32>()
+                    .get(index)
+                    .ok_or(MemAccessFault)
+            }
+        } else {
+            let entry = self.find_device_by_page(page).ok_or(MemAccessFault)?;
+            entry.interface.get_atomic_word(page - entry.base, offset)
         }
     }
 }