Enable NVRAM to be read/stored

src/bus.rs

@@ -6,6 +6,8 @@ use crate::err::DuartError;
 use std::fmt::Debug;
 use std::ops::Range;
 
+const NVRAM_SIZE: usize = 8192;
+
 /// Access Status Code
 pub enum AccessCode {
     MoveTranslated,
@@ -208,6 +210,22 @@ impl Bus {
     pub fn duart_output(&self) -> u8 {
         self.duart.output_port()
     }
+
+    pub fn get_nvram(&self) -> [u8; NVRAM_SIZE] {
+        let mut contents: [u8; NVRAM_SIZE] = [0u8; NVRAM_SIZE];
+
+        for i in 0..NVRAM_SIZE {
+            contents[i] = self.bbram[i];
+        }
+
+        contents
+    }
+
+    pub fn set_nvram(&mut self, nvram: &[u8; NVRAM_SIZE]) {
+        for (i, b) in nvram.into_iter().enumerate() {
+            self.bbram[i] = *b;
+        }
+    }
 }
 
 #[cfg(test)]

src/dmd.rs

@@ -150,6 +150,20 @@ impl Dmd {
     pub fn duart_output(&self) -> u8 {
         self.bus.duart_output()
     }
+
+    ///
+    /// Load NVRAM into the emulator
+    ///
+    pub fn set_nvram(&mut self, nvram: &[u8; 8192]) {
+        self.bus.set_nvram(nvram);
+    }
+
+    ///
+    /// Get NVRAM from the emulator
+    ///
+    pub fn get_nvram(&self) -> [u8; 8192] {
+        self.bus.get_nvram()
+    }
 }
 
 #[cfg(test)]

src/mem.rs

@@ -4,7 +4,7 @@ use crate::err::BusError;
 use std::fmt::Debug;
 use std::fmt::Error;
 use std::fmt::Formatter;
-use std::ops::Index;
+use std::ops::{Index, IndexMut};
 use std::vec::Vec;
 use std::ops::Range;
 
@@ -168,6 +168,12 @@ impl Index<usize> for Mem {
     }
 }
 
+impl IndexMut<usize> for Mem {
+    fn index_mut<'a>(&'a mut self, idx: usize) -> &'a mut u8 {
+        &mut self.ram[idx]
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;