SoftwareBypasser.cc

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/*
    Copyright (c) 2002-2009 Tampere University.
 
    This file is part of TTA-Based Codesign Environment (TCE).
 
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/**
 * @file SoftwareBypasser.cc
 *
 * Definition of SoftwareBypasser interface.
 *
 * @author Pekka Jääskeläinen 2007 (pjaaskel-no.spam-cs.tut.fi)
 * @note rating: red
 */
 
#include "SoftwareBypasser.hh"
 
#include "MoveNodeGroup.hh"
#include "DataDependenceGraph.hh"
#include "ResourceManager.hh"
 
/**
 * Empty constructor.
 */
SoftwareBypasser::SoftwareBypasser() : bypassCount_(0), deadResultCount_(0){
}
 
/**
 * Empty destructor.
 */
SoftwareBypasser::~SoftwareBypasser() {
}
 
/**
 * Apply software bypassing to as many moves in the given MoveNodeGroup
 * as possible.
 *
 * The given DDG can be used to inspect whether software bypassing is possible.
 *
 * @param candidates The moves to which apply software bypassing, if possible.
 * @param ddg The data dependence grap in which the movenodes belong to.
 * @param rm The resource manager which is used to check for resource
 *        availability.
 * @param bypassTrigger whether to bypass the trigger or not.
 * @return The count of bypassed moves.
 */
int
SoftwareBypasser::bypass(
    MoveNodeGroup& candidates,
    DataDependenceGraph& ddg,
    ResourceManager& rm, 
    bool /*bypassTrigger*/) {
 
    // use the arguments just to avoid compiler warnings with strict flags
    candidates.nodeCount();
    ddg.nodeCount();
    rm.machine();
    return 0;
}
 
/**
 * Remove software bypassing from as many moves in the given MoveNodeGroup
 * as possible.
 *
 * @param candidates The moves from which to remove software bypassing, if
 * possible.
 * @param ddg The data dependence grap in which the movenodes belong to.
 * @param rm The resource manager which is used to check for resource
 *        availability.
 */
void
SoftwareBypasser::removeBypass(
    MoveNodeGroup& candidates,
    DataDependenceGraph& ddg,
    ResourceManager& rm) {
 
    // use the arguments just to avoid compiler warnings with strict flags
    candidates.nodeCount();
    ddg.nodeCount();
    rm.machine();
    return;
}
 
/**
 * Remove dead result moves for each bypassed move of given MoveNodeGroup
 * if possible. That is, no other result reads of result exists.
 * This assumes that result moves in MoveNodeGroup are also scheduled.
 *
 * @param candidates The moves for which remove dead result writes
 * @param ddg The data dependence grap in which the movenodes belong to.
 * @param rm The resource manager which is used to check for resource
 *        availability.
 * @param removedMoves The dead result eliminated moves and their original 
 * cycles, to allow rescheduling of moves that were previously
 * resource (RF write port usually) constrained by the removed moves.
 * @return number of dead results killed
 */
int
SoftwareBypasser::removeDeadResults(
    MoveNodeGroup& candidates,
    DataDependenceGraph& ddg,
    ResourceManager& rm,
    std::set<std::pair<TTAProgram::Move*, int> >& removedMoves) {
 
    // use the arguments just to avoid compiler warnings with strict flags
    candidates.nodeCount();
    ddg.nodeCount();
    rm.machine();
    removedMoves.begin();
    return 0;
}
 
/*
 * Registers the selector being used to the bypasser.
 *
 * If the bypasser has been registered to the selector,
 * bypasses can notify the selector about dependence changes
 * (like WAR/WAW edge removal duo bypassing)
 *
 * Default implementation is empty, only actual bypasser implementations 
 * implement this.
 *
 * @param selector selector which bypasser notifies on some dependence changes.
 */
void 
SoftwareBypasser::setSelector(MoveNodeSelector*) {
}