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/*
* Copyright (c) 2005-2006 The Regents of The University of Michigan
* Copyright (c) 2013 Advanced Micro Devices, Inc.
* 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: Korey Sewell
* Kevin Lim
* Steve Reinhardt
*/
#ifndef __CPU_O3_SCOREBOARD_HH__
#define __CPU_O3_SCOREBOARD_HH__
#include <iostream>
#include <utility>
#include <vector>
#include "base/trace.hh"
#include "config/the_isa.hh"
#include "cpu/o3/comm.hh"
#include "debug/Scoreboard.hh"
/**
* Implements a simple scoreboard to track which registers are
* ready. This class operates on the unified physical register space,
* so integer and floating-point registers are not distinguished. For
* convenience, it also accepts operations on the physical-space
* mapping of misc registers, which are numbered starting after the
* end of the actual physical register file. However, there is no
* actual scoreboard for misc registers, and they are always
* considered ready.
*/
class Scoreboard
{
private:
/** The object name, for DPRINTF. We have to declare this
* explicitly because Scoreboard is not a SimObject. */
const std::string _name;
/** Scoreboard of physical integer registers, saying whether or not they
* are ready. */
std::vector<bool> regScoreBoard;
/** The number of actual physical registers */
unsigned numPhysRegs;
/**
* The total number of registers which can be indexed, including
* the misc registers that come after the physical registers and
* which are hardwired to be always considered ready.
*/
unsigned numTotalRegs;
/** The index of the zero register. */
PhysRegIndex zeroRegIdx;
/** The index of the FP zero register. */
PhysRegIndex fpZeroRegIdx;
bool isZeroReg(PhysRegIndex idx) const
{
return (idx == zeroRegIdx ||
(THE_ISA == ALPHA_ISA && idx == fpZeroRegIdx));
}
public:
/** Constructs a scoreboard.
* @param _numPhysicalRegs Number of physical registers.
* @param _numMiscRegs Number of miscellaneous registers.
* @param _zeroRegIdx Index of the zero register.
* @param _fpZeroRegIdx Index of the FP zero register (if any, currently
* used only for Alpha).
*/
Scoreboard(const std::string &_my_name,
unsigned _numPhysicalRegs,
unsigned _numMiscRegs,
PhysRegIndex _zeroRegIdx,
PhysRegIndex _fpZeroRegIdx);
/** Destructor. */
~Scoreboard() {}
/** Returns the name of the scoreboard. */
std::string name() const { return _name; };
/** Checks if the register is ready. */
bool getReg(PhysRegIndex reg_idx) const
{
assert(reg_idx < numTotalRegs);
if (reg_idx >= numPhysRegs) {
// misc regs are always ready
return true;
}
bool ready = regScoreBoard[reg_idx];
if (isZeroReg(reg_idx))
assert(ready);
return ready;
}
/** Sets the register as ready. */
void setReg(PhysRegIndex reg_idx)
{
assert(reg_idx < numTotalRegs);
if (reg_idx >= numPhysRegs) {
// misc regs are always ready, ignore attempts to change that
return;
}
DPRINTF(Scoreboard, "Setting reg %i as ready\n", reg_idx);
assert(reg_idx < numTotalRegs);
regScoreBoard[reg_idx] = true;
}
/** Sets the register as not ready. */
void unsetReg(PhysRegIndex reg_idx)
{
assert(reg_idx < numTotalRegs);
if (reg_idx >= numPhysRegs) {
// misc regs are always ready, ignore attempts to change that
return;
}
// zero reg should never be marked unready
if (isZeroReg(reg_idx))
return;
regScoreBoard[reg_idx] = false;
}
};
#endif
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