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Diffstat (limited to 'src/cpu/o3/decode.hh')
| -rw-r--r-- | src/cpu/o3/decode.hh | 165 |
1 files changed, 165 insertions, 0 deletions
diff --git a/src/cpu/o3/decode.hh b/src/cpu/o3/decode.hh new file mode 100644 index 000000000..5b9a0f822 --- /dev/null +++ b/src/cpu/o3/decode.hh @@ -0,0 +1,165 @@ +/* + * Copyright (c) 2004-2005 The Regents of The University of Michigan + * 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 __CPU_O3_CPU_SIMPLE_DECODE_HH__ +#define __CPU_O3_CPU_SIMPLE_DECODE_HH__ + +#include <queue> + +#include "base/statistics.hh" +#include "base/timebuf.hh" + +template<class Impl> +class SimpleDecode +{ + private: + // Typedefs from the Impl. + typedef typename Impl::FullCPU FullCPU; + typedef typename Impl::DynInstPtr DynInstPtr; + typedef typename Impl::Params Params; + typedef typename Impl::CPUPol CPUPol; + + // Typedefs from the CPU policy. + typedef typename CPUPol::FetchStruct FetchStruct; + typedef typename CPUPol::DecodeStruct DecodeStruct; + typedef typename CPUPol::TimeStruct TimeStruct; + + public: + // The only time decode will become blocked is if dispatch becomes + // blocked, which means IQ or ROB is probably full. + enum Status { + Running, + Idle, + Squashing, + Blocked, + Unblocking + }; + + private: + // May eventually need statuses on a per thread basis. + Status _status; + + public: + SimpleDecode(Params ¶ms); + + void regStats(); + + void setCPU(FullCPU *cpu_ptr); + + void setTimeBuffer(TimeBuffer<TimeStruct> *tb_ptr); + + void setDecodeQueue(TimeBuffer<DecodeStruct> *dq_ptr); + + void setFetchQueue(TimeBuffer<FetchStruct> *fq_ptr); + + void tick(); + + void decode(); + + private: + inline bool fetchInstsValid(); + + void block(); + + inline void unblock(); + + void squash(DynInstPtr &inst); + + public: + // Might want to make squash a friend function. + void squash(); + + private: + // Interfaces to objects outside of decode. + /** CPU interface. */ + FullCPU *cpu; + + /** Time buffer interface. */ + TimeBuffer<TimeStruct> *timeBuffer; + + /** Wire to get rename's output from backwards time buffer. */ + typename TimeBuffer<TimeStruct>::wire fromRename; + + /** Wire to get iew's information from backwards time buffer. */ + typename TimeBuffer<TimeStruct>::wire fromIEW; + + /** Wire to get commit's information from backwards time buffer. */ + typename TimeBuffer<TimeStruct>::wire fromCommit; + + /** Wire to write information heading to previous stages. */ + // Might not be the best name as not only fetch will read it. + typename TimeBuffer<TimeStruct>::wire toFetch; + + /** Decode instruction queue. */ + TimeBuffer<DecodeStruct> *decodeQueue; + + /** Wire used to write any information heading to rename. */ + typename TimeBuffer<DecodeStruct>::wire toRename; + + /** Fetch instruction queue interface. */ + TimeBuffer<FetchStruct> *fetchQueue; + + /** Wire to get fetch's output from fetch queue. */ + typename TimeBuffer<FetchStruct>::wire fromFetch; + + /** Skid buffer between fetch and decode. */ + std::queue<FetchStruct> skidBuffer; + + //Consider making these unsigned to avoid any confusion. + /** Rename to decode delay, in ticks. */ + unsigned renameToDecodeDelay; + + /** IEW to decode delay, in ticks. */ + unsigned iewToDecodeDelay; + + /** Commit to decode delay, in ticks. */ + unsigned commitToDecodeDelay; + + /** Fetch to decode delay, in ticks. */ + unsigned fetchToDecodeDelay; + + /** The width of decode, in instructions. */ + unsigned decodeWidth; + + /** The instruction that decode is currently on. It needs to have + * persistent state so that when a stall occurs in the middle of a + * group of instructions, it can restart at the proper instruction. + */ + unsigned numInst; + + Stats::Scalar<> decodeIdleCycles; + Stats::Scalar<> decodeBlockedCycles; + Stats::Scalar<> decodeUnblockCycles; + Stats::Scalar<> decodeSquashCycles; + Stats::Scalar<> decodeBranchMispred; + Stats::Scalar<> decodeControlMispred; + Stats::Scalar<> decodeDecodedInsts; + Stats::Scalar<> decodeSquashedInsts; +}; + +#endif // __CPU_O3_CPU_SIMPLE_DECODE_HH__ |