1 files changed, 160 insertions, 0 deletions
diff --git a/cpu/beta_cpu/tournament_pred.hh b/cpu/beta_cpu/tournament_pred.hh
new file mode 100644
index 000000000..bf87d753b
--- /dev/null
+++ b/cpu/beta_cpu/tournament_pred.hh
@@ -0,0 +1,160 @@
+#ifndef __TOURNAMENT_PRED_HH__
+#define __TOURNAMENT_PRED_HH__
+
+// For Addr type.
+#include "arch/alpha/isa_traits.hh"
+
+class TournamentBP
+{
+  public:
+    /**
+     * Default branch predictor constructor.
+     */
+    TournamentBP(unsigned local_predictor_size,
+                 unsigned local_ctr_bits,
+                 unsigned local_history_table_size,
+                 unsigned local_history_bits,
+                 unsigned global_predictor_size,
+                 unsigned global_history_bits,
+                 unsigned global_ctr_bits,
+                 unsigned choice_predictor_size,
+                 unsigned choice_ctr_bits,
+                 unsigned instShiftAmt);
+
+    /**
+     * Looks up the given address in the branch predictor and returns
+     * a true/false value as to whether it is taken.
+     * @param branch_addr The address of the branch to look up.
+     * @return Whether or not the branch is taken.
+     */
+    bool lookup(Addr &branch_addr);
+
+    /**
+     * Updates the branch predictor with the actual result of a branch.
+     * @param branch_addr The address of the branch to update.
+     * @param taken Whether or not the branch was taken.
+     */
+    void update(Addr &branch_addr, unsigned global_history, bool taken);
+
+    inline unsigned readGlobalHist() { return global_history; }
+
+  private:
+
+    inline bool getPrediction(uint8_t &count);
+
+    inline unsigned calcLocHistIdx(Addr &branch_addr);
+
+    inline void updateHistoriesTaken(unsigned local_history_idx);
+
+    inline void updateHistoriesNotTaken(unsigned local_history_idx);
+
+    /**
+     * Private counter class for the internal saturating counters.
+     * Implements an n bit saturating counter and provides methods to
+     * increment, decrement, and read it.
+     * @todo Consider making this something that more closely mimics a
+     * built in class so you can use ++ or --.
+     */
+    class SatCounter
+    {
+      public:
+        /**
+         * Constructor for the counter.
+         * @param bits How many bits the counter will have.
+         */
+        SatCounter(unsigned bits);
+
+        /**
+         * Constructor for the counter.
+         * @param bits How many bits the counter will have.
+         * @param initial_val Starting value for each counter.
+         */
+        SatCounter(unsigned bits, unsigned initial_val);
+
+        /**
+         * Increments the counter's current value.
+         */
+        void increment();
+
+        /**
+         * Decrements the counter's current value.
+         */
+        void decrement();
+
+        /**
+         * Read the counter's value.
+         */
+        uint8_t read()
+        {
+            return counter;
+        }
+
+      private:
+        uint8_t maxVal;
+        uint8_t counter;
+    };
+
+    /** Local counters. */
+    SatCounter *local_ctrs;
+
+    /** Size of the local predictor. */
+    unsigned local_predictor_size;
+
+    /** Number of bits of the local predictor's counters. */
+    unsigned local_ctr_bits;
+
+    /** Array of local history table entries. */
+    unsigned *local_history_table;
+
+    /** Size of the local history table. */
+    unsigned local_history_table_size;
+
+    /** Number of bits for each entry of the local history table.
+     *  @todo Doesn't this come from the size of the local predictor?
+     */
+    unsigned local_history_bits;
+
+    /** Mask to get the proper local history. */
+    unsigned localHistoryMask;
+
+
+    /** Array of counters that make up the global predictor. */
+    SatCounter *global_ctrs;
+
+    /** Size of the global predictor. */
+    unsigned global_predictor_size;
+
+    /** Number of bits of the global predictor's counters. */
+    unsigned global_ctr_bits;
+
+    /** Global history register. */
+    unsigned global_history;
+
+    /** Number of bits for the global history. */
+    unsigned global_history_bits;
+
+    /** Mask to get the proper global history. */
+    unsigned globalHistoryMask;
+
+
+    /** Array of counters that make up the choice predictor. */
+    SatCounter *choice_ctrs;
+
+    /** Size of the choice predictor (identical to the global predictor). */
+    unsigned choice_predictor_size;
+
+    /** Number of bits of the choice predictor's counters. */
+    unsigned choice_ctr_bits;
+
+    /** Number of bits to shift the instruction over to get rid of the word
+     *  offset.
+     */
+    unsigned instShiftAmt;
+
+    /** Threshold for the counter value; above the threshold is taken,
+     *  equal to or below the threshold is not taken.
+     */
+    unsigned threshold;
+};
+
+#endif // __TOURNAMENT_PRED_HH__