1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/modules/bluespec/Pygar/core/InstCacheBlocking.d	Fri Apr 23 02:32:05 2010 -0400
     1.3 @@ -0,0 +1,269 @@
     1.4 +// The MIT License
     1.5 +
     1.6 +// Copyright (c) 2009 Massachusetts Institute of Technology
     1.7 +
     1.8 +// Permission is hereby granted, free of charge, to any person obtaining a copy
     1.9 +// of this software and associated documentation files (the "Software"), to deal
    1.10 +// in the Software without restriction, including without limitation the rights
    1.11 +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    1.12 +// copies of the Software, and to permit persons to whom the Software is
    1.13 +// furnished to do so, subject to the following conditions:
    1.14 +
    1.15 +// The above copyright notice and this permission notice shall be included in
    1.16 +// all copies or substantial portions of the Software.
    1.17 +
    1.18 +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    1.19 +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    1.20 +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    1.21 +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    1.22 +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    1.23 +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    1.24 +// THE SOFTWARE.
    1.25 +
    1.26 +import Connectable::*;
    1.27 +import GetPut::*;
    1.28 +import ClientServer::*;
    1.29 +import RegFile::*;
    1.30 +import FIFO::*;
    1.31 +import FIFOF::*;
    1.32 +import RWire::*;
    1.33 +
    1.34 +import BFIFO::*;
    1.35 +import MemTypes::*;
    1.36 +import ProcTypes::*;
    1.37 +import Trace::*;
    1.38 +
    1.39 +interface ICacheStats;
    1.40 +  interface Get#(Stat) num_accesses;
    1.41 +  interface Get#(Stat) num_misses;
    1.42 +  interface Get#(Stat) num_evictions;
    1.43 +endinterface
    1.44 +
    1.45 +interface ICache#( type req_t, type resp_t );
    1.46 +
    1.47 +  // Interface from processor to cache
    1.48 +  interface Server#(req_t,resp_t) proc_server;
    1.49 +
    1.50 +  // Interface from cache to main memory
    1.51 +  interface Client#(MainMemReq,MainMemResp) mmem_client;
    1.52 +
    1.53 +  // Interface for enabling/disabling statistics
    1.54 +  interface Put#(Bool) statsEn_put;
    1.55 +
    1.56 +  // Interface for collecting statistics
    1.57 +  interface ICacheStats stats;
    1.58 +
    1.59 +endinterface
    1.60 +
    1.61 +//----------------------------------------------------------------------
    1.62 +// Cache Types
    1.63 +//----------------------------------------------------------------------
    1.64 +
    1.65 +typedef 10 CacheLineIndexSz;
    1.66 +typedef 20 CacheLineTagSz;
    1.67 +typedef 32 CacheLineSz;
    1.68 +
    1.69 +typedef Bit#(CacheLineIndexSz) CacheLineIndex;
    1.70 +typedef Bit#(CacheLineTagSz)   CacheLineTag;
    1.71 +typedef Bit#(CacheLineSz)      CacheLine;
    1.72 +
    1.73 +typedef enum 
    1.74 +{ 
    1.75 +  Init,
    1.76 +  Access, 
    1.77 +  Evict, 
    1.78 +  RefillReq, 
    1.79 +  RefillResp 
    1.80 +} 
    1.81 +CacheStage 
    1.82 +deriving (Eq,Bits);
    1.83 +
    1.84 +//----------------------------------------------------------------------
    1.85 +// Helper functions
    1.86 +//----------------------------------------------------------------------
    1.87 +
    1.88 +function Bit#(AddrSz) getAddr( InstReq req );
    1.89 +
    1.90 +  Bit#(AddrSz) addr = ?;
    1.91 +  case ( req ) matches
    1.92 +    tagged LoadReq  .ld : addr = ld.addr;
    1.93 +    tagged StoreReq .st : addr = st.addr;
    1.94 +  endcase
    1.95 +
    1.96 +  return addr;
    1.97 +
    1.98 +endfunction
    1.99 +
   1.100 +function CacheLineIndex getCacheLineIndex( InstReq req );
   1.101 +  Bit#(AddrSz) addr = getAddr(req);
   1.102 +  Bit#(CacheLineIndexSz) index = truncate( addr >> 2 );
   1.103 +  return index;
   1.104 +endfunction
   1.105 +
   1.106 +function CacheLineTag getCacheLineTag( InstReq req );
   1.107 +  Bit#(AddrSz)         addr = getAddr(req);
   1.108 +  Bit#(CacheLineTagSz) tag  = truncate( addr >> fromInteger(valueOf(CacheLineIndexSz)) >> 2 );
   1.109 +  return tag;
   1.110 +endfunction
   1.111 +
   1.112 +function Bit#(AddrSz) getCacheLineAddr( InstReq req );
   1.113 +  Bit#(AddrSz) addr = getAddr(req);
   1.114 +  return ((addr >> 2) << 2);
   1.115 +endfunction
   1.116 +
   1.117 +//----------------------------------------------------------------------
   1.118 +// Main module
   1.119 +//----------------------------------------------------------------------
   1.120 +
   1.121 +(* doc = "synthesis attribute ram_style mkInstCache distributed;" *)
   1.122 +(* synthesize *)
   1.123 +module mkInstCache( ICache#(InstReq,InstResp) );
   1.124 +
   1.125 +  //-----------------------------------------------------------
   1.126 +  // State
   1.127 +
   1.128 +  Reg#(CacheStage) stage <- mkReg(Init);
   1.129 +
   1.130 +  RegFile#(CacheLineIndex,Maybe#(CacheLineTag)) cacheTagRam  <- mkRegFileFull();
   1.131 +  RegFile#(CacheLineIndex,CacheLine)            cacheDataRam <- mkRegFileFull();
   1.132 +
   1.133 +  FIFO#(InstReq)   reqQ  <- mkFIFO();
   1.134 +  FIFOF#(InstResp) respQ <- mkBFIFOF1();
   1.135 +
   1.136 +  FIFO#(MainMemReq)  mainMemReqQ  <- mkBFIFO1();
   1.137 +  FIFO#(MainMemResp) mainMemRespQ <- mkFIFO();
   1.138 +
   1.139 +  Reg#(CacheLineIndex) initCounter <- mkReg(1);
   1.140 +
   1.141 +  // Statistics state
   1.142 +
   1.143 +  Reg#(Bool)     statsEn        <- mkReg(False);
   1.144 +
   1.145 +  Reg#(Stat) numAccesses <- mkReg(0);
   1.146 +  Reg#(Stat) numMisses <- mkReg(0);
   1.147 +  Reg#(Stat) numEvictions <- mkReg(0);
   1.148 +
   1.149 +  //-----------------------------------------------------------
   1.150 +  // Name some wires
   1.151 +
   1.152 +  let req              = reqQ.first();
   1.153 +  let reqIndex         = getCacheLineIndex(req);
   1.154 +  let reqTag           = getCacheLineTag(req);
   1.155 +  let reqCacheLineAddr = getCacheLineAddr(req);
   1.156 +  let refill           = mainMemRespQ.first();
   1.157 +
   1.158 +  //-----------------------------------------------------------
   1.159 +  // Initialize
   1.160 +
   1.161 +  rule init ( stage == Init );
   1.162 +    traceTiny("mkInstCacheBlocking", "stage","i");
   1.163 +    initCounter <= initCounter + 1;
   1.164 +    cacheTagRam.upd(initCounter,Invalid);
   1.165 +    if ( initCounter == 0 )
   1.166 +      stage <= Access;
   1.167 +  endrule
   1.168 +
   1.169 +  //-----------------------------------------------------------
   1.170 +  // Cache access rule
   1.171 +
   1.172 +  rule access ( (stage == Access) && respQ.notFull() );
   1.173 +
   1.174 +    // Statistics
   1.175 +
   1.176 +    if ( statsEn )
   1.177 +      numAccesses <= numAccesses + 1;
   1.178 +  
   1.179 +    // Check tag and valid bit to see if this is a hit or a miss
   1.180 +
   1.181 +    Maybe#(CacheLineTag) cacheLineTag = cacheTagRam.sub(reqIndex);
   1.182 +  
   1.183 +    // Handle cache hits ...
   1.184 +
   1.185 +    if ( isValid(cacheLineTag) && ( unJust(cacheLineTag) == reqTag ) )
   1.186 +     begin
   1.187 +       traceTiny("mkInstCacheBlocking", "hitMiss","h");
   1.188 +       reqQ.deq();
   1.189 +
   1.190 +       case ( req ) matches
   1.191 +          
   1.192 +         tagged LoadReq .ld :
   1.193 +	  respQ.enq( LoadResp { tag  : ld.tag, data : cacheDataRam.sub(reqIndex) } );
   1.194 +
   1.195 +         tagged StoreReq .st :
   1.196 +          $display( " RTL-ERROR : %m : Stores are not allowed on the inst port!" );
   1.197 +       
   1.198 +       endcase
   1.199 +
   1.200 +     end
   1.201 +
   1.202 +    // Handle cache misses - since lines in instruction cache are
   1.203 +    // never dirty we can always immediately issue a refill request
   1.204 +    
   1.205 +    else 
   1.206 +     begin
   1.207 +       traceTiny("mkInstCacheBlocking", "hitMiss","m");
   1.208 +       if ( statsEn )
   1.209 +         numMisses <= numMisses + 1;
   1.210 +       if ( statsEn )
   1.211 +         if ( isJust(cacheLineTag) )
   1.212 +           numEvictions <= numEvictions + 1;
   1.213 +
   1.214 +       MainMemReq rfReq
   1.215 +        = LoadReq { tag  : 0,
   1.216 +	            addr : reqCacheLineAddr };
   1.217 +
   1.218 +       mainMemReqQ.enq(rfReq);
   1.219 +       stage <= RefillResp;    
   1.220 +     end
   1.221 +
   1.222 +  endrule
   1.223 +
   1.224 +  //-----------------------------------------------------------
   1.225 +  // Refill response rule
   1.226 +  
   1.227 +   rule refillResp ( stage == RefillResp );
   1.228 +    traceTiny("mkInstCacheBlocking", "stage","R");
   1.229 +    traceTiny("mkInstCacheBlocking", "refill",refill);
   1.230 +
   1.231 +    // Write the new data into the cache and update the tag
   1.232 +
   1.233 +    mainMemRespQ.deq();
   1.234 +    case ( mainMemRespQ.first() ) matches
   1.235 +
   1.236 +      tagged LoadResp .ld :
   1.237 +       begin
   1.238 +	 cacheTagRam.upd(reqIndex,Valid(reqTag));
   1.239 +	 cacheDataRam.upd(reqIndex,ld.data);	
   1.240 +       end
   1.241 +       
   1.242 +      tagged StoreResp .st :
   1.243 +	noAction;
   1.244 +     
   1.245 +    endcase
   1.246 +
   1.247 +    stage <= Access;
   1.248 +  endrule
   1.249 +
   1.250 +  //-----------------------------------------------------------
   1.251 +  // Methods
   1.252 +
   1.253 +  interface Client mmem_client;
   1.254 +    interface Get request  = fifoToGet(mainMemReqQ);
   1.255 +    interface Put response = fifoToPut(mainMemRespQ);
   1.256 +  endinterface
   1.257 +
   1.258 +  interface Server proc_server;
   1.259 +    interface Put request  = tracePut("mkInstCacheBlocking", "reqTiny",toPut(reqQ));
   1.260 +    interface Get response = traceGet("mkInstCacheBlocking", "respTiny",toGet(respQ));
   1.261 +  endinterface
   1.262 +
   1.263 +  interface Put statsEn_put = toPut(asReg(statsEn));
   1.264 +
   1.265 +  interface ICacheStats stats;
   1.266 +    interface Get num_accesses = toGet(asReg(numAccesses));
   1.267 +    interface Get num_misses = toGet(asReg(numMisses));
   1.268 +    interface Get num_evictions = toGet(asReg(numEvictions));
   1.269 +  endinterface
   1.270 +
   1.271 +endmodule
   1.272 +