/*
 * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
 * 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.
 */

#ifndef __MEM_RUBY_STOREBUFFER_STOREBUFFER_HH__
#define __MEM_RUBY_STOREBUFFER_STOREBUFFER_HH__

#include <deque>
#include <map>

#include "mem/ruby/common/TypeDefines.hh"
#include "mem/ruby/slicc_interface/RubyRequest.hh"

/**
 *  Status for write buffer accesses. The Write buffer can hit in
 *  fastpath, be full, or successfully enqueue the store request
 */
enum storebuffer_status_t { WB_FULL, WB_OK, WB_FLUSHING };

/**
 *  Status of a load match
 */
enum load_match { NO_MATCH, PARTIAL_MATCH, FULL_MATCH };

struct SBEntry
{
    RubyRequest m_request;

    SBEntry(RubyRequest request, void * ptr)
        : m_request(request)
    {
    }
};

class StoreBuffer
{
  public:
    /// Note that the size of the Write Buffer is determined by the
    /// WRITE_BUFFER_SIZE config parameter
    StoreBuffer(uint32_t id, uint32_t block_bits, int storebuffer_size);

    ~StoreBuffer();

    /// Register hitcallback back to CPU
    void registerHitCallback(void (*hit_callback)(int64_t request_id));

    ///Adds a store entry to the write buffer
    void addToStoreBuffer(RubyRequest request);

    ///Flushes the entire write buffer
    void flushStoreBuffer();

    ///A pseq object calls this when Ruby completes our request
    void complete(uint64_t);

    /// Returns ID. If ID == -2, HIT, else it's an ID to wait on
    int64_t handleLoad(RubyRequest request);

    /// Used by all load insts to check whether it hits to any entry
    /// in the WB. If so, the WB is flushed
    load_match checkForLoadHit(RubyRequest request);

    /// Used to fill the load in case of FULL_MATCH
    void returnMatchedData(RubyRequest request);

    /// Issue next store in line
    void issueNextStore();

    /// prints out the contents of the Write Buffer
    void print();

    /// Returns flag indicating whether we are using the write buffer
    bool useStoreBuffer() { return m_use_storebuffer; }

    bool storeBufferFull() { return m_storebuffer_full; }

    bool storeBufferFlushing() { return m_storebuffer_flushing; }

  private:
    /// id of this write buffer (one per sequencer object)
    uint32_t m_id;

    /// number of bytes in cacheline
    uint32_t m_block_size;

    /// the size of the write buffer
    uint32_t m_storebuffer_size;

    /// mask to strip off non-cache line bits
    pa_t m_block_mask;

    /// list of store requests in the write buffer
    std::deque<SBEntry> buffer;

    /// the current length of the write buffer
    uint32_t m_buffer_size;

    /// whether we want to simulate the write buffer or not:
    bool m_use_storebuffer;

    /// indicates whether the write buffer is full or not
    bool m_storebuffer_full;

    /// indicates that we are currently flushing the write buffer
    bool m_storebuffer_flushing;

    /// indicates that automatic issue is stalled and the next store
    /// to be added should issue itself
    bool m_stalled_issue;

    /// RubyPort to make requests to
    RubyPortHandle m_port;

    /// HitCallback to CPU
    void (*m_hit_callback)(int64_t);

    /// Map the request id to rubyrequest
    std::map<uint64_t, RubyRequest> outstanding_requests;

    /// current instruction counter
    uint64_t iseq;

    /// input into tso counter
    uint64_t tso_iseq;
};

#endif //  __MEM_RUBY_STOREBUFFER_STOREBUFFER_HH__