Adding gem5 source to svn.

git-svn-id: https://www4.informatik.uni-erlangen.de/i4svn/danceos/trunk/devel/fail@1819 8c4709b5-6ec9-48aa-a5cd-a96041d1645a

simulators/gem5/src/arch/alpha/decoder.hh

@@ -0,0 +1,130 @@
+/*
+ * Copyright (c) 2012 Google
+ * 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: Gabe Black
+ */
+
+#ifndef __ARCH_ALPHA_DECODER_HH__
+#define __ARCH_ALPHA_DECODER_HH__
+
+#include "arch/generic/decode_cache.hh"
+#include "arch/types.hh"
+#include "cpu/static_inst.hh"
+#include "sim/full_system.hh"
+
+class ThreadContext;
+
+namespace AlphaISA
+{
+
+class Decoder
+{
+  protected:
+    ThreadContext *tc;
+
+    // The extended machine instruction being generated
+    ExtMachInst ext_inst;
+    bool instDone;
+
+  public:
+    Decoder(ThreadContext * _tc) : tc(_tc), instDone(false)
+    {}
+
+    ThreadContext *
+    getTC()
+    {
+        return tc;
+    }
+
+    void
+    setTC(ThreadContext * _tc)
+    {
+        tc = _tc;
+    }
+
+    void
+    process()
+    { }
+
+    void
+    reset()
+    {
+        instDone = false;
+    }
+
+    // Use this to give data to the predecoder. This should be used
+    // when there is control flow.
+    void
+    moreBytes(const PCState &pc, Addr fetchPC, MachInst inst)
+    {
+        ext_inst = inst;
+        instDone = true;
+        if (FullSystem)
+            ext_inst |= (static_cast<ExtMachInst>(pc.pc() & 0x1) << 32);
+    }
+
+    bool
+    needMoreBytes()
+    {
+        return true;
+    }
+
+    bool
+    instReady()
+    {
+        return instDone;
+    }
+
+  protected:
+    /// A cache of decoded instruction objects.
+    static GenericISA::BasicDecodeCache defaultCache;
+
+  public:
+    StaticInstPtr decodeInst(ExtMachInst mach_inst);
+
+    /// Decode a machine instruction.
+    /// @param mach_inst The binary instruction to decode.
+    /// @retval A pointer to the corresponding StaticInst object.
+    StaticInstPtr
+    decode(ExtMachInst mach_inst, Addr addr)
+    {
+        return defaultCache.decode(this, mach_inst, addr);
+    }
+
+    StaticInstPtr
+    decode(AlphaISA::PCState &nextPC)
+    {
+        if (!instDone)
+            return NULL;
+        instDone = false;
+        return decode(ext_inst, nextPC.instAddr());
+    }
+};
+
+} // namespace AlphaISA
+
+#endif // __ARCH_ALPHA_DECODER_HH__