src/mem/protocol/atomic.hh

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 * modified or unmodified, in source code or in binary form.
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 * All rights reserved.
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#ifndef __MEM_GEM5_PROTOCOL_ATOMIC_HH__
#define __MEM_GEM5_PROTOCOL_ATOMIC_HH__

#include "mem/backdoor.hh"
#include "mem/packet.hh"

class AtomicResponseProtocol;

class AtomicRequestProtocol
{
    friend class AtomicResponseProtocol;

  protected:
    /**
     * Send an atomic request packet, where the data is moved and the
     * state is updated in zero time, without interleaving with other
     * memory accesses.
     *
     * @param peer Peer to send packet to.
     * @param pkt Packet to send.
     *
     * @return Estimated latency of access.
     */
    Tick send(AtomicResponseProtocol *peer, PacketPtr pkt);

    /**
     * Send an atomic request packet like above, but also request a backdoor
     * to the data being accessed.
     *
     * @param peer Peer to send packet to.
     * @param pkt Packet to send.
     * @param backdoor Can be set to a back door pointer by the target to let
     *        caller have direct access to the requested data.
     *
     * @return Estimated latency of access.
     */
    Tick sendBackdoor(AtomicResponseProtocol *peer, PacketPtr pkt,
                      MemBackdoorPtr &backdoor);

    /**
     * Receive an atomic snoop request packet from our peer.
     */
    virtual Tick recvAtomicSnoop(PacketPtr pkt) = 0;
};

class AtomicResponseProtocol
{
    friend class AtomicRequestProtocol;

  protected:
    /**
     * Send an atomic snoop request packet, where the data is moved
     * and the state is updated in zero time, without interleaving
     * with other memory accesses.
     *
     * @param peer Peer to send packet to.
     * @param pkt Snoop packet to send.
     *
     * @return Estimated latency of access.
     */
    Tick sendSnoop(AtomicRequestProtocol *peer, PacketPtr pkt);

    /**
     * Receive an atomic request packet from the peer.
     */
    virtual Tick recvAtomic(PacketPtr pkt) = 0;

    /**
     * Receive an atomic request packet from the peer, and optionally
     * provide a backdoor to the data being accessed.
     */
    virtual Tick recvAtomicBackdoor(
            PacketPtr pkt, MemBackdoorPtr &backdoor) = 0;
};

#endif //__MEM_GEM5_PROTOCOL_ATOMIC_HH__