src/cpu/o3/rename_map.cc

/*
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 * Copyright (c) 2004-2005 The Regents of The University of Michigan
 * Copyright (c) 2013 Advanced Micro Devices, Inc.
 * All rights reserved.
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 * modification, are permitted provided that the following conditions are
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#include "cpu/o3/rename_map.hh"

#include <vector>

#include "arch/vecregs.hh"
#include "cpu/o3/dyn_inst.hh"
#include "cpu/reg_class.hh"
#include "debug/Rename.hh"

namespace gem5
{

namespace o3
{

SimpleRenameMap::SimpleRenameMap()
    : freeList(NULL), zeroReg(IntRegClass, 0)
{
}


void
SimpleRenameMap::init(const RegClass &reg_class, SimpleFreeList *_freeList)
{
    assert(freeList == NULL);
    assert(map.empty());

    map.resize(reg_class.numRegs());
    freeList = _freeList;
    zeroReg = RegId(IntRegClass, reg_class.zeroReg());
}

SimpleRenameMap::RenameInfo
SimpleRenameMap::rename(const RegId& arch_reg)
{
    PhysRegIdPtr renamed_reg;
    // Record the current physical register that is renamed to the
    // requested architected register.
    PhysRegIdPtr prev_reg = map[arch_reg.index()];

    if (arch_reg == zeroReg) {
        assert(prev_reg->index() == zeroReg.index());
        renamed_reg = prev_reg;
    } else if (prev_reg->getNumPinnedWrites() > 0) {
        // Do not rename if the register is pinned
        assert(arch_reg.getNumPinnedWrites() == 0);  // Prevent pinning the
                                                     // same register twice
        DPRINTF(Rename, "Renaming pinned reg, numPinnedWrites %d\n",
                prev_reg->getNumPinnedWrites());
        renamed_reg = prev_reg;
        renamed_reg->decrNumPinnedWrites();
    } else {
        renamed_reg = freeList->getReg();
        map[arch_reg.index()] = renamed_reg;
        renamed_reg->setNumPinnedWrites(arch_reg.getNumPinnedWrites());
        renamed_reg->setNumPinnedWritesToComplete(
            arch_reg.getNumPinnedWrites() + 1);
    }

    DPRINTF(Rename, "Renamed reg %d to physical reg %d (%d) old mapping was"
            " %d (%d)\n",
            arch_reg, renamed_reg->flatIndex(), renamed_reg->flatIndex(),
            prev_reg->flatIndex(), prev_reg->flatIndex());

    return RenameInfo(renamed_reg, prev_reg);
}


/**** UnifiedRenameMap methods ****/

void
UnifiedRenameMap::init(const BaseISA::RegClasses &regClasses,
        PhysRegFile *_regFile, UnifiedFreeList *freeList)
{
    regFile = _regFile;

    for (int i = 0; i < renameMaps.size(); i++)
        renameMaps[i].init(regClasses.at(i), &(freeList->freeLists[i]));
}

bool
UnifiedRenameMap::canRename(DynInstPtr inst) const
{
    for (int i = 0; i < renameMaps.size(); i++) {
        if (inst->numDestRegs((RegClassType)i) >
                renameMaps[i].numFreeEntries()) {
            return false;
        }
    }
    return true;
}

} // namespace o3
} // namespace gem5