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Removed the CMO_WRITEBACK state from the cache.

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Rose Thompson 2023-11-20 20:52:11 -06:00
parent 667fe035c0
commit 5fb3c83efc
1 changed files with 13 additions and 17 deletions
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30
src/cache/cachefsm.sv vendored
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@ -91,8 +91,7 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
STATE_FLUSH, STATE_FLUSH,
STATE_FLUSH_WRITEBACK, STATE_FLUSH_WRITEBACK,
// CMO states // CMO states
STATE_CMO_WRITEBACK, STATE_CMO_WRITEBACK
STATE_CMO_DONE
} statetype; } statetype;
statetype CurrState, NextState; statetype CurrState, NextState;
@ -125,8 +124,8 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
STATE_READY: if(InvalidateCache) NextState = STATE_READY; // exclusion-tag: dcache InvalidateCheck STATE_READY: if(InvalidateCache) NextState = STATE_READY; // exclusion-tag: dcache InvalidateCheck
else if(FlushCache & ~READ_ONLY_CACHE) NextState = STATE_FLUSH; else if(FlushCache & ~READ_ONLY_CACHE) NextState = STATE_FLUSH;
else if(AnyMiss & (READ_ONLY_CACHE | ~LineDirty)) NextState = STATE_FETCH; // exclusion-tag: icache FETCHStatement else if(AnyMiss & (READ_ONLY_CACHE | ~LineDirty)) NextState = STATE_FETCH; // exclusion-tag: icache FETCHStatement
else if(AnyMiss | CMOZeroEviction) NextState = STATE_WRITEBACK; // exclusion-tag: icache WRITEBACKStatement else if(AnyMiss | CMOZeroEviction | CMOWritebackHit) NextState = STATE_WRITEBACK; // exclusion-tag: icache WRITEBACKStatement
else if(CMOWritebackHit) NextState = STATE_CMO_WRITEBACK; //else if(CMOWritebackHit) NextState = STATE_CMO_WRITEBACK;
else NextState = STATE_READY; else NextState = STATE_READY;
STATE_FETCH: if(CacheBusAck) NextState = STATE_WRITE_LINE; STATE_FETCH: if(CacheBusAck) NextState = STATE_WRITE_LINE;
else if(CacheBusAck) NextState = STATE_READY; else if(CacheBusAck) NextState = STATE_READY;
@ -135,7 +134,8 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
STATE_READ_HOLD: if(Stall) NextState = STATE_READ_HOLD; STATE_READ_HOLD: if(Stall) NextState = STATE_READ_HOLD;
else NextState = STATE_READY; else NextState = STATE_READY;
// exclusion-tag-start: icache case // exclusion-tag-start: icache case
STATE_WRITEBACK: if(CacheBusAck & ~CMOp[3]) NextState = STATE_FETCH; STATE_WRITEBACK: if (CacheBusAck & (CMOp[1] | CMOp[2])) NextState = STATE_READ_HOLD;
else if(CacheBusAck & ~CMOp[3]) NextState = STATE_FETCH;
else if(CacheBusAck) NextState = STATE_READ_HOLD; else if(CacheBusAck) NextState = STATE_READ_HOLD;
else NextState = STATE_WRITEBACK; else NextState = STATE_WRITEBACK;
// eviction needs a delay as the bus fsm does not correctly handle sending the write command at the same time as getting back the bus ack. // eviction needs a delay as the bus fsm does not correctly handle sending the write command at the same time as getting back the bus ack.
@ -148,29 +148,26 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
STATE_CMO_WRITEBACK: if(CacheBusAck & (CMOp[1] | CMOp[2])) NextState = STATE_READ_HOLD; STATE_CMO_WRITEBACK: if(CacheBusAck & (CMOp[1] | CMOp[2])) NextState = STATE_READ_HOLD;
else NextState = STATE_CMO_WRITEBACK; else NextState = STATE_CMO_WRITEBACK;
STATE_CMO_DONE: if(Stall) NextState = STATE_CMO_DONE;
else NextState = STATE_READY;
// exclusion-tag-end: icache case // exclusion-tag-end: icache case
default: NextState = STATE_READY; default: NextState = STATE_READY;
endcase endcase
end end
// com back to CPU // com back to CPU
assign CacheCommitted = (CurrState != STATE_READY) & ~(READ_ONLY_CACHE & (CurrState == STATE_READ_HOLD | CurrState == STATE_CMO_DONE)); assign CacheCommitted = (CurrState != STATE_READY) & ~(READ_ONLY_CACHE & (CurrState == STATE_READ_HOLD));
assign CacheStall = (CurrState == STATE_READY & (FlushCache | AnyMiss | CMOWritebackHit | CMOZeroEviction)) | // exclusion-tag: icache StallStates assign CacheStall = (CurrState == STATE_READY & (FlushCache | AnyMiss | CMOWritebackHit | CMOZeroEviction)) | // exclusion-tag: icache StallStates
(CurrState == STATE_FETCH) | (CurrState == STATE_FETCH) |
(CurrState == STATE_WRITEBACK) | (CurrState == STATE_WRITEBACK) |
(CurrState == STATE_WRITE_LINE) | // this cycle writes the sram, must keep stalling so the next cycle can read the next hit/miss unless its a write. (CurrState == STATE_WRITE_LINE) | // this cycle writes the sram, must keep stalling so the next cycle can read the next hit/miss unless its a write.
(CurrState == STATE_FLUSH) | (CurrState == STATE_FLUSH) |
(CurrState == STATE_FLUSH_WRITEBACK) | (CurrState == STATE_FLUSH_WRITEBACK);
(CurrState == STATE_CMO_WRITEBACK);
// write enables internal to cache // write enables internal to cache
assign CMOZeroHit = CurrState == STATE_READY & CMOp[3] & CacheHit ; assign CMOZeroHit = CurrState == STATE_READY & CMOp[3] & CacheHit ;
assign SetValid = CurrState == STATE_WRITE_LINE | assign SetValid = CurrState == STATE_WRITE_LINE |
(P.ZICBOZ_SUPPORTED & CurrState == STATE_READY & CMOZeroNoEviction) | (P.ZICBOZ_SUPPORTED & CurrState == STATE_READY & CMOZeroNoEviction) |
(P.ZICBOZ_SUPPORTED & CurrState == STATE_WRITEBACK & CacheBusAck & CMOp[3]); (P.ZICBOZ_SUPPORTED & CurrState == STATE_WRITEBACK & CacheBusAck & CMOp[3]);
assign ClearValid = P.ZICBOM_SUPPORTED & ((CurrState == STATE_READY & CMOp[0] & CacheHit) | assign ClearValid = P.ZICBOM_SUPPORTED & ((CurrState == STATE_READY & CMOp[0] & CacheHit) |
(CurrState == STATE_CMO_WRITEBACK & CMOp[2] & CacheBusAck)); (CurrState == STATE_WRITEBACK & CMOp[2] & CacheBusAck));
// coverage off -item e 1 -fecexprrow 8 // coverage off -item e 1 -fecexprrow 8
assign LRUWriteEn = (((CurrState == STATE_READY & (AnyHit | CMOZeroNoEviction)) | assign LRUWriteEn = (((CurrState == STATE_READY & (AnyHit | CMOZeroNoEviction)) |
(CurrState == STATE_WRITE_LINE)) & ~FlushStage) | (CurrState == STATE_WRITE_LINE)) & ~FlushStage) |
@ -182,7 +179,7 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
assign ClearDirty = (CurrState == STATE_WRITE_LINE & ~(CacheRW[0])) | // exclusion-tag: icache ClearDirty assign ClearDirty = (CurrState == STATE_WRITE_LINE & ~(CacheRW[0])) | // exclusion-tag: icache ClearDirty
(CurrState == STATE_FLUSH & LineDirty) | // This is wrong in a multicore snoop cache protocal. Dirty must be cleared concurrently and atomically with writeback. For single core cannot clear after writeback on bus ack and change flushadr. Clears the wrong set. (CurrState == STATE_FLUSH & LineDirty) | // This is wrong in a multicore snoop cache protocal. Dirty must be cleared concurrently and atomically with writeback. For single core cannot clear after writeback on bus ack and change flushadr. Clears the wrong set.
// Flush and eviction controls // Flush and eviction controls
(P.ZICBOM_SUPPORTED & CurrState == STATE_CMO_WRITEBACK & (CMOp[1] | CMOp[2]) & CacheBusAck); (P.ZICBOM_SUPPORTED & CurrState == STATE_WRITEBACK & (CMOp[1] | CMOp[2]) & CacheBusAck);
assign SelWay = SelWriteback | (CurrState == STATE_WRITE_LINE) | assign SelWay = SelWriteback | (CurrState == STATE_WRITE_LINE) |
// This is almost the same as setvalid, but on cachehit we don't want to select // This is almost the same as setvalid, but on cachehit we don't want to select
// the nonhit way, but instead want to force this to zero // the nonhit way, but instead want to force this to zero
@ -190,9 +187,9 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
(P.ZICBOZ_SUPPORTED & CurrState == STATE_WRITEBACK & CacheBusAck & CMOp[3]); (P.ZICBOZ_SUPPORTED & CurrState == STATE_WRITEBACK & CacheBusAck & CMOp[3]);
assign ZeroCacheLine = P.ZICBOZ_SUPPORTED & ((CurrState == STATE_READY & CMOZeroNoEviction) | assign ZeroCacheLine = P.ZICBOZ_SUPPORTED & ((CurrState == STATE_READY & CMOZeroNoEviction) |
(CurrState == STATE_WRITEBACK & (CMOp[3] & CacheBusAck))); (CurrState == STATE_WRITEBACK & (CMOp[3] & CacheBusAck)));
assign SelWriteback = (CurrState == STATE_WRITEBACK & ~CacheBusAck) | assign SelWriteback = (CurrState == STATE_WRITEBACK & ~CacheBusAck & ~(CMOp[1] | CMOp[2])) |
(CurrState == STATE_READY & AnyMiss & LineDirty); (CurrState == STATE_READY & AnyMiss & LineDirty);
assign SelCMOWriteback = CurrState == STATE_CMO_WRITEBACK; assign SelCMOWriteback = CurrState == STATE_WRITEBACK & (CMOp[1] | CMOp[2]);
assign SelFlush = (CurrState == STATE_READY & FlushCache) | assign SelFlush = (CurrState == STATE_READY & FlushCache) |
(CurrState == STATE_FLUSH) | (CurrState == STATE_FLUSH) |
@ -209,17 +206,16 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
// Bus interface controls // Bus interface controls
assign CacheBusRW[1] = (CurrState == STATE_READY & AnyMiss & ~LineDirty) | // exclusion-tag: icache CacheBusRCauses assign CacheBusRW[1] = (CurrState == STATE_READY & AnyMiss & ~LineDirty) | // exclusion-tag: icache CacheBusRCauses
(CurrState == STATE_FETCH & ~CacheBusAck) | (CurrState == STATE_FETCH & ~CacheBusAck) |
(CurrState == STATE_WRITEBACK & CacheBusAck & ~CMOp[3]); (CurrState == STATE_WRITEBACK & CacheBusAck & ~(|CMOp));
assign CacheBusRW[0] = (CurrState == STATE_READY & AnyMiss & LineDirty) | // exclusion-tag: icache CacheBusW assign CacheBusRW[0] = (CurrState == STATE_READY & AnyMiss & LineDirty) | // exclusion-tag: icache CacheBusW
(CurrState == STATE_WRITEBACK & ~CacheBusAck) | (CurrState == STATE_WRITEBACK & ~CacheBusAck) |
(CurrState == STATE_FLUSH_WRITEBACK & ~CacheBusAck) | (CurrState == STATE_FLUSH_WRITEBACK & ~CacheBusAck) |
(P.ZICBOM_SUPPORTED & CurrState == STATE_CMO_WRITEBACK & (CMOp[1] | CMOp[2]) & ~CacheBusAck); (P.ZICBOM_SUPPORTED & CurrState == STATE_WRITEBACK & (CMOp[1] | CMOp[2]) & ~CacheBusAck);
assign SelAdr = (CurrState == STATE_READY & (CacheRW[0] | AnyMiss | (|CMOp))) | // exclusion-tag: icache SelAdrCauses // changes if store delay hazard removed assign SelAdr = (CurrState == STATE_READY & (CacheRW[0] | AnyMiss | (|CMOp))) | // exclusion-tag: icache SelAdrCauses // changes if store delay hazard removed
(CurrState == STATE_FETCH) | (CurrState == STATE_FETCH) |
(CurrState == STATE_WRITEBACK) | (CurrState == STATE_WRITEBACK) |
(CurrState == STATE_WRITE_LINE) | (CurrState == STATE_WRITE_LINE) |
(CurrState == STATE_CMO_WRITEBACK) |
resetDelay; resetDelay;
assign SelFetchBuffer = CurrState == STATE_WRITE_LINE | CurrState == STATE_READ_HOLD; assign SelFetchBuffer = CurrState == STATE_WRITE_LINE | CurrState == STATE_READ_HOLD;
assign CacheEn = (~Stall | FlushCache | AnyMiss) | (CurrState != STATE_READY) | reset | InvalidateCache; // exclusion-tag: dcache CacheEn assign CacheEn = (~Stall | FlushCache | AnyMiss) | (CurrState != STATE_READY) | reset | InvalidateCache; // exclusion-tag: dcache CacheEn