cpu: `Minor' in-order CPU model

This patch contains a new CPU model named `Minor'. Minor models a four
stage in-order execution pipeline (fetch lines, decompose into
macroops, decompose macroops into microops, execute).

The model was developed to support the ARM ISA but should be fixable
to support all the remaining gem5 ISAs. It currently also works for
Alpha, and regressions are included for ARM and Alpha (including Linux
boot).

Documentation for the model can be found in src/doc/inside-minor.doxygen and
its internal operations can be visualised using the Minorview tool
utils/minorview.py.

Minor was designed to be fairly simple and not to engage in a lot of
instruction annotation. As such, it currently has very few gathered
stats and may lack other gem5 features.

Minor is faster than the o3 model. Sample results:

     Benchmark     |   Stat host_seconds (s)
    ---------------+--------v--------v--------
     (on ARM, opt) | simple | o3     | minor
                   | timing | timing | timing
    ---------------+--------+--------+--------
    10.linux-boot  |   169  |  1883  |  1075
    10.mcf         |   117  |   967  |   491
    20.parser      |   668  |  6315  |  3146
    30.eon         |   542  |  3413  |  2414
    40.perlbmk     |  2339  | 20905  | 11532
    50.vortex      |   122  |  1094  |   588
    60.bzip2       |  2045  | 18061  |  9662
    70.twolf       |   207  |  2736  |  1036

1 files changed, 216 insertions, 0 deletions

diff --git a/src/cpu/timing_expr.hh b/src/cpu/timing_expr.hh
new file mode 100644
index 000000000..d2c38ea90
--- /dev/null
+++ b/src/cpu/timing_expr.hh
@@ -0,0 +1,216 @@
+/*
+ * Copyright (c) 2013-2014 ARM Limited
+ * All rights reserved.
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * 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: Andrew Bardsley
+ */
+
+/*
+ * These classes define an expression language over uint64_t with only
+ * a few operators.  This can be used to form expressions for the extra
+ * delay required in variable execution time instructions.
+ *
+ * Expressions, in evaluation, will have access to the ThreadContext and
+ * a StaticInst.
+ */
+
+#ifndef __CPU_TIMING_EXPR_HH__
+#define __CPU_TIMING_EXPR_HH__
+
+#include "cpu/static_inst.hh"
+#include "cpu/thread_context.hh"
+#include "enums/TimingExprOp.hh"
+#include "params/TimingExpr.hh"
+#include "params/TimingExprBin.hh"
+#include "params/TimingExprIf.hh"
+#include "params/TimingExprLet.hh"
+#include "params/TimingExprLiteral.hh"
+#include "params/TimingExprReadIntReg.hh"
+#include "params/TimingExprRef.hh"
+#include "params/TimingExprSrcReg.hh"
+#include "params/TimingExprUn.hh"
+#include "sim/sim_object.hh"
+
+/** These classes are just the C++ counterparts for those in Expr.py and
+ *  are, therefore, documented there */
+
+class TimingExprLet;
+
+/** Object to gather the visible context for evaluation */
+class TimingExprEvalContext
+{
+  public:
+    /** Special visible context */
+    StaticInstPtr inst;
+    ThreadContext *thread;
+
+    /** Context visible as sub expressions.  results will hold the results
+     *  of (lazily) evaluating let's expressions.  resultAvailable elements
+     *  are true when a result has actually been evaluated */
+    TimingExprLet *let;
+    std::vector<uint64_t> results;
+    std::vector<bool > resultAvailable;
+
+    TimingExprEvalContext(StaticInstPtr inst_,
+        ThreadContext *thread_, TimingExprLet *let_);
+};
+
+class TimingExpr : public SimObject
+{
+  public:
+    TimingExpr(const TimingExprParams *params) :
+        SimObject(params)
+    { }
+
+    virtual uint64_t eval(TimingExprEvalContext &context) = 0;
+};
+
+class TimingExprLiteral : public TimingExpr
+{
+  public:
+    uint64_t value;
+
+    TimingExprLiteral(const TimingExprLiteralParams *params) :
+        TimingExpr(params),
+        value(params->value)
+    { }
+
+    uint64_t eval(TimingExprEvalContext &context) { return value; }
+};
+
+class TimingExprSrcReg : public TimingExpr
+{
+  public:
+    unsigned int index;
+
+    TimingExprSrcReg(const TimingExprSrcRegParams *params) :
+        TimingExpr(params),
+        index(params->index)
+    { }
+
+    uint64_t eval(TimingExprEvalContext &context);
+};
+
+class TimingExprReadIntReg : public TimingExpr
+{
+  public:
+    TimingExpr *reg;
+
+    TimingExprReadIntReg(const TimingExprReadIntRegParams *params) :
+        TimingExpr(params),
+        reg(params->reg)
+    { }
+
+    uint64_t eval(TimingExprEvalContext &context);
+};
+
+class TimingExprLet : public TimingExpr
+{
+  public:
+    std::vector<TimingExpr *> defns;
+    TimingExpr *expr;
+
+    TimingExprLet(const TimingExprLetParams *params) :
+        TimingExpr(params),
+        defns(params->defns),
+        expr(params->expr)
+    { }
+
+    uint64_t eval(TimingExprEvalContext &context);
+};
+
+class TimingExprRef : public TimingExpr
+{
+  public:
+    unsigned int index;
+
+    TimingExprRef(const TimingExprRefParams *params) :
+        TimingExpr(params),
+        index(params->index)
+    { }
+
+    uint64_t eval(TimingExprEvalContext &context);
+};
+
+class TimingExprUn : public TimingExpr
+{
+  public:
+    Enums::TimingExprOp op;
+    TimingExpr *arg;
+
+    TimingExprUn(const TimingExprUnParams *params) :
+        TimingExpr(params),
+        op(params->op),
+        arg(params->arg)
+    { }
+
+    uint64_t eval(TimingExprEvalContext &context);
+};
+
+class TimingExprBin : public TimingExpr
+{
+  public:
+    Enums::TimingExprOp op;
+    TimingExpr *left;
+    TimingExpr *right;
+
+    TimingExprBin(const TimingExprBinParams *params) :
+        TimingExpr(params),
+        op(params->op),
+        left(params->left),
+        right(params->right)
+    { }
+
+    uint64_t eval(TimingExprEvalContext &context);
+};
+
+class TimingExprIf : public TimingExpr
+{
+  public:
+    TimingExpr *cond;
+    TimingExpr *trueExpr;
+    TimingExpr *falseExpr;
+
+    TimingExprIf(const TimingExprIfParams *params) :
+        TimingExpr(params),
+        cond(params->cond),
+        trueExpr(params->trueExpr),
+        falseExpr(params->falseExpr)
+    { }
+
+    uint64_t eval(TimingExprEvalContext &context);
+};
+
+#endif