[mem] Add mapped memory

src/emu/mem.rs

@@ -0,0 +1,28 @@
+use crate::emu::mmu::Memory;
+
+const MEM_LENGTH: usize = 2 << 24;
+
+#[derive(Clone, Debug)]
+pub struct RamMemory {
+    data: Box<[u8; MEM_LENGTH]>,
+}
+
+impl RamMemory {
+    pub fn new() -> RamMemory {
+        RamMemory {
+            data: vec![0; MEM_LENGTH].into_boxed_slice().try_into().expect("Incorrect ram allocation")
+        }
+    }
+}
+
+impl Memory for RamMemory {
+    fn get_byte(&self, address: u32) -> u8 {
+        log::trace!("Fetch RAM memory at address {}",address);
+        let x = *self.data.get(address as usize).expect("Unchecked address fetch");
+        x
+    }
+
+    fn set_byte(&mut self, address: u32, val: u8) {
+        self.data[address as usize] = val;
+    }
+}