boxswap

core/src/periph/at28c256/default.rs

@@ -9,7 +9,11 @@ impl Default for At28C256 {
         let boxed_array: Box<[u8; SIZE_32KB]> = boxed_slice
             .try_into()
             .expect("Failed to convert Vec to boxed array");
-        At28C256 { data: boxed_array }
+        At28C256 { data: boxed_array,
+        address_bus: 0x0000,
+        data_bus: 0x00,
+        offset: 0x0000
+        }
     }
 }
 

core/src/periph/at28c256/dump.rs

@@ -0,0 +1,13 @@
+use crate::periph::at28c256::At28C256;
+
+pub struct At28C256State {
+    offset: u16
+}
+
+impl At28C256 {
+    pub fn dump(&self) -> At28C256State {
+        At28C256State {
+            offset: self.offset
+        }
+    }
+}

core/src/periph/at28c256/mod.rs

@@ -3,6 +3,7 @@ pub mod rom_chip;
 pub mod tick;
 mod new;
 mod program;
+mod dump;
 
 use crate::constants::constants_system::SIZE_32KB;
 use crate::periph::rom_chip::RomChip;
@@ -15,7 +16,11 @@ use std::io::Read;
 /// 256kbit storage
 /// 32kbyte storage
 pub struct At28C256 {
+    data_bus: u8,
+    address_bus: u16,
     data: Box<[u8; SIZE_32KB]>,
+    // where in the computer memory map do we live?
+    offset: u16
 }
 
 #[cfg(test)]

core/src/periph/at28c256/new.rs

@@ -2,9 +2,12 @@ use crate::constants::constants_system::SIZE_32KB;
 use crate::periph::at28c256::At28C256;
 
 impl At28C256 {
-    pub fn new(data: &[u8; SIZE_32KB]) -> Self {
+    pub fn new(offset: u16, data: &[u8; SIZE_32KB]) -> Self {
         At28C256 {
-            data: (*data).into()
+            data: (*data).into(),
+            address_bus: 0x0000,
+            data_bus: 0x00,
+            offset
         }
     }
 }

core/src/periph/at28c256/tick.rs

@@ -1,14 +1,23 @@
+use crate::constants::constants_system::SIZE_32KB;
 use crate::periph::at28c256::At28C256;
 use crate::periph::hm62256::Hm62256;
 
 impl At28C256 {
-    fn tick(&mut self, address_bus: u16, data_bus: u8, read_mode: bool) -> (u16, u8) {
-        if read_mode {
-            panic!("UNABLE TO WRITE TO ROM");
-        } else {
-        // has to be read mode.  its a rom.
-            return (address_bus, data_bus)
+    fn max_address(&self) -> u16 {
+        self.offset + SIZE_32KB as u16
+    }
+
+
+    pub fn tick(&mut self, address_bus: u16, data_bus: u8, read_mode: bool) -> (u16, u8) {
+        if address_bus.gt(&self.offset) & address_bus.lt(&self.max_address()) {
+            if read_mode {
+                panic!("UNABLE TO WRITE TO ROM");
+            } else {
+                // has to be read mode.  its a rom.
+                return (address_bus, data_bus)
+            }
         }
+        // not for us.
         (address_bus, self.data[address_bus as usize])
     }
 }