Merge ktlim@zizzer.eecs.umich.edu:/bk/m5

into zamp.eecs.umich.edu:/z/ktlim2/m5

--HG--
extra : convert_revision : a58535776cf5a3d17f8d9f65144cdf8db54289aa

1 files changed, 54 insertions, 0 deletions

diff --git a/cpu/beta_cpu/2bit_local_pred.hh b/cpu/beta_cpu/2bit_local_pred.hh
new file mode 100644
index 000000000..cda7d3e65
--- /dev/null
+++ b/cpu/beta_cpu/2bit_local_pred.hh
@@ -0,0 +1,54 @@
+#ifndef __CPU_BETA_CPU_2BIT_LOCAL_PRED_HH__
+#define __CPU_BETA_CPU_2BIT_LOCAL_PRED_HH__
+
+// For Addr type.
+#include "arch/alpha/isa_traits.hh"
+#include "cpu/beta_cpu/sat_counter.hh"
+
+class DefaultBP
+{
+  public:
+    /**
+     * Default branch predictor constructor.
+     */
+    DefaultBP(unsigned localPredictorSize, unsigned localCtrBits,
+              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, bool taken);
+
+  private:
+
+    inline bool getPrediction(uint8_t &count);
+
+    inline unsigned getLocalIndex(Addr &PC);
+
+    /** Array of counters that make up the local predictor. */
+    SatCounter *localCtrs;
+
+    /** Size of the local predictor. */
+    unsigned localPredictorSize;
+
+    /** Number of bits of the local predictor's counters. */
+    unsigned localCtrBits;
+
+    /** Number of bits to shift the PC when calculating index. */
+    unsigned instShiftAmt;
+
+    /** Mask to get index bits. */
+    unsigned indexMask;
+};
+
+#endif // __CPU_BETA_CPU_2BIT_LOCAL_PRED_HH__