branch predictor: move out of o3 and inorder cpus

This patch moves the branch predictor files in the o3 and inorder directories
to src/cpu/pred. This allows sharing the branch predictor across different
cpu models.

This patch was originally posted by Timothy Jones in July 2010
but never made it to the repository.

--HG--
rename : src/cpu/o3/bpred_unit.cc => src/cpu/pred/bpred_unit.cc
rename : src/cpu/o3/bpred_unit.hh => src/cpu/pred/bpred_unit.hh
rename : src/cpu/o3/bpred_unit_impl.hh => src/cpu/pred/bpred_unit_impl.hh
rename : src/cpu/o3/sat_counter.hh => src/cpu/pred/sat_counter.hh

1 files changed, 117 insertions, 0 deletions

diff --git a/src/cpu/pred/sat_counter.hh b/src/cpu/pred/sat_counter.hh
new file mode 100644
index 000000000..1294a4e08
--- /dev/null
+++ b/src/cpu/pred/sat_counter.hh
@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) 2005-2006 The Regents of The University of Michigan
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met: redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer;
+ * redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution;
+ * neither the name of the copyright holders nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Authors: Kevin Lim
+ */
+
+#ifndef __CPU_PRED_SAT_COUNTER_HH__
+#define __CPU_PRED_SAT_COUNTER_HH__
+
+#include "base/misc.hh"
+#include "base/types.hh"
+
+/**
+ * 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.
+     */
+    SatCounter()
+        : initialVal(0), counter(0)
+    { }
+
+    /**
+     * Constructor for the counter.
+     * @param bits How many bits the counter will have.
+     */
+    SatCounter(unsigned bits)
+        : initialVal(0), maxVal((1 << bits) - 1), counter(0)
+    { }
+
+    /**
+     * Constructor for the counter.
+     * @param bits How many bits the counter will have.
+     * @param initial_val Starting value for each counter.
+     */
+    SatCounter(unsigned bits, uint8_t initial_val)
+        : initialVal(initial_val), maxVal((1 << bits) - 1),
+          counter(initial_val)
+    {
+        // Check to make sure initial value doesn't exceed the max
+        // counter value.
+        if (initial_val > maxVal) {
+            fatal("BP: Initial counter value exceeds max size.");
+        }
+    }
+
+    /**
+     * Sets the number of bits.
+     */
+    void setBits(unsigned bits) { maxVal = (1 << bits) - 1; }
+
+    void reset() { counter = initialVal; }
+
+    /**
+     * Increments the counter's current value.
+     */
+    void increment()
+    {
+        if (counter < maxVal) {
+            ++counter;
+        }
+    }
+
+    /**
+     * Decrements the counter's current value.
+     */
+    void decrement()
+    {
+        if (counter > 0) {
+            --counter;
+        }
+    }
+
+    /**
+     * Read the counter's value.
+     */
+    const uint8_t read() const
+    { return counter; }
+
+  private:
+    uint8_t initialVal;
+    uint8_t maxVal;
+    uint8_t counter;
+};
+
+#endif // __CPU_PRED_SAT_COUNTER_HH__