simple_btb.cc

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#include "cpu/pred/simple_btb.hh"
 
#include "base/intmath.hh"
#include "base/trace.hh"
#include "debug/BTB.hh"
 
namespace gem5::branch_prediction
{
 
SimpleBTB::SimpleBTB(const SimpleBTBParams &p)
    : BranchTargetBuffer(p),
      btb("simpleBTB", p.numEntries, p.associativity,
          p.btbReplPolicy, p.btbIndexingPolicy,
          BTBEntry(genTagExtractor(p.btbIndexingPolicy)))
{
    DPRINTF(BTB, "BTB: Creating BTB object.\n");
 
    if (!isPowerOf2(p.numEntries)) {
        fatal("BTB entries is not a power of 2!");
    }
}
SimpleBTB::SimpleBTB(const SimpleBTBParams &p) {…}
 
void
SimpleBTB::memInvalidate()
{
    btb.clear();
}
SimpleBTB::memInvalidate() {…}
 
BTBEntry *
SimpleBTB::findEntry(Addr instPC, ThreadID tid)
{
    return btb.findEntry({instPC, tid});
}
SimpleBTB::findEntry(Addr instPC, ThreadID tid) {…}
 
bool
SimpleBTB::valid(ThreadID tid, Addr instPC)
{
    BTBEntry *entry = btb.findEntry({instPC, tid});
 
    return entry != nullptr;
}
SimpleBTB::valid(ThreadID tid, Addr instPC) {…}
 
// @todo Create some sort of return struct that has both whether or not the
// address is valid, and also the address.  For now will just use addr = 0 to
// represent invalid entry.
const PCStateBase *
SimpleBTB::lookup(ThreadID tid, Addr instPC, BranchType type)
{
    stats.lookups[type]++;
 
    BTBEntry *entry = btb.accessEntry({instPC, tid});
 
    if (entry) {
        return entry->target.get();
    }
 
    stats.misses[type]++;
    return nullptr;
}
SimpleBTB::lookup(ThreadID tid, Addr instPC, BranchType type) {…}
 
const StaticInstPtr
SimpleBTB::getInst(ThreadID tid, Addr instPC)
{
    BTBEntry *entry = btb.findEntry({instPC, tid});
 
    if (entry) {
        return entry->inst;
    }
 
    return nullptr;
}
SimpleBTB::getInst(ThreadID tid, Addr instPC) {…}
 
void
SimpleBTB::update(ThreadID tid, Addr instPC,
                  const PCStateBase &target,
                  BranchType type, StaticInstPtr inst)
{
    stats.updates[type]++;
 
    BTBEntry *victim = btb.findVictim({instPC, tid});
 
    btb.insertEntry({instPC, tid}, victim);
    victim->update(target, inst);
}
SimpleBTB::update(ThreadID tid, Addr instPC, {…}
 
 
} // namespace gem5::branch_prediction