From ad805c698cd1c4d68d090f842fb14621c32ee8d6 Mon Sep 17 00:00:00 2001
From: David Li <li.davidm96@gmail.com>
Date: Fri, 8 Jan 2016 10:04:27 -0700
Subject: Refactor into multiple files

---
 src/shareable_cache.rs | 104 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100644 src/shareable_cache.rs

(limited to 'src/shareable_cache.rs')

diff --git a/src/shareable_cache.rs b/src/shareable_cache.rs
new file mode 100644
index 0000000..b6c6654
--- /dev/null
+++ b/src/shareable_cache.rs
@@ -0,0 +1,104 @@
+use rustv::isa;
+use rustv::memory::{MemoryInterface, Result, SharedMemory};
+
+/// A cache that can be used as two separate caches or one
+/// set-associative cache.
+struct ShareableCache<'a> {
+    // The idea is to create two separate ShareableCaches, one for
+    // each player.
+    primary: SharedMemory<'a>,
+    secondary: SharedMemory<'a>,
+    secondary_enabled: bool,
+    use_secondary: bool,
+}
+
+impl<'a> ShareableCache<'a> {
+    pub fn new(cache1: SharedMemory<'a>, cache2: SharedMemory<'a>)
+           -> (ShareableCache<'a>, ShareableCache<'a>) {
+        (ShareableCache {
+            primary: cache1.clone(),
+            secondary: cache2.clone(),
+            secondary_enabled: false,
+            use_secondary: false,
+        }, ShareableCache {
+            primary: cache2.clone(),
+            secondary: cache1.clone(),
+            secondary_enabled: false,
+            use_secondary: false,
+        })
+    }
+
+    pub fn enable_secondary(&mut self) {
+        self.secondary_enabled = true;
+        self.use_secondary = true;
+    }
+
+    pub fn disable_secondary(&mut self) {
+        self.secondary_enabled = false;
+    }
+}
+
+impl<'a> MemoryInterface for ShareableCache<'a> {
+    fn latency(&self) -> u32 {
+        self.primary.borrow().latency()
+    }
+
+    fn step(&mut self) {
+        // We only step the primary cache. The idea is that the
+        // secondary cache should be the primary cache of another
+        // ShareableCache.
+        self.primary.borrow_mut().step();
+    }
+
+    fn is_address_accessible(&self, address: isa::Address) -> bool {
+        self.primary.borrow().is_address_accessible(address) ||
+            (self.secondary_enabled &&
+             self.secondary.borrow().is_address_accessible(address))
+    }
+
+    fn read_word(&mut self, address: isa::Address) -> Result<isa::Word> {
+        if self.secondary_enabled {
+            if self.primary.borrow().is_address_accessible(address) {
+                self.primary.borrow_mut().read_word(address)
+            }
+            else if self.secondary.borrow().is_address_accessible(address) {
+                self.secondary.borrow_mut().read_word(address)
+            }
+            else {
+                self.use_secondary = !self.use_secondary;
+                if self.use_secondary {
+                    self.secondary.borrow_mut().read_word(address)
+                }
+                else {
+                    self.primary.borrow_mut().read_word(address)
+                }
+            }
+        }
+        else {
+            self.primary.borrow_mut().read_word(address)
+        }
+    }
+
+    fn write_word(&mut self, address: isa::Address, value: isa::Word) -> Result<()> {
+        if self.secondary_enabled {
+            if self.primary.borrow().is_address_accessible(address) {
+                self.primary.borrow_mut().write_word(address, value)
+            }
+            else if self.secondary.borrow().is_address_accessible(address) {
+                self.secondary.borrow_mut().write_word(address, value)
+            }
+            else {
+                self.use_secondary = !self.use_secondary;
+                if self.use_secondary {
+                    self.secondary.borrow_mut().write_word(address, value)
+                }
+                else {
+                    self.primary.borrow_mut().write_word(address, value)
+                }
+            }
+        }
+        else {
+            self.primary.borrow_mut().write_word(address, value)
+        }
+    }
+}
-- 
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