Merge pull request #651 from ross144/main

Updates to cache logic.  Code quality improvements.
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David Harris 2024-03-06 13:45:01 -08:00 committed by GitHub
commit af1ecfc30d
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18 changed files with 105 additions and 109 deletions

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@ -21,7 +21,7 @@ ROOT := ..
LIBRARY_DIRS :=
LIBRARY_FILES :=
MARCH :=-march=rv64imfdc
MARCH :=-march=rv64imfdc_zifencei
MABI :=-mabi=lp64d
LINK_FLAGS :=$(MARCH) $(MABI) -nostartfiles
LINKER :=linker.x

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@ -94,5 +94,5 @@ end_of_bios:
.globl _dtb
.align 4, 0
_dtb:
.incbin "wally-vcu118.dtb"
#.incbin "wally-vcu118.dtb"

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@ -1,7 +1,7 @@
///////////////////////////////////////////
// SDC.sv
//
// Written: Ross Thompson September 25, 2021
// Written: Rose Thompson September 25, 2021
// Modified:
//
// Purpose: driver for sdc reader.

16
src/cache/cache.sv vendored
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@ -82,7 +82,7 @@ module cache import cvw::*; #(parameter cvw_t P,
logic ClearDirty, SetDirty, SetValid, ClearValid;
logic [LINELEN-1:0] ReadDataLineWay [NUMWAYS-1:0];
logic [NUMWAYS-1:0] HitWay, ValidWay;
logic CacheHit;
logic Hit;
logic [NUMWAYS-1:0] VictimWay, DirtyWay, HitDirtyWay;
logic LineDirty, HitLineDirty;
logic [TAGLEN-1:0] TagWay [NUMWAYS-1:0];
@ -98,7 +98,7 @@ module cache import cvw::*; #(parameter cvw_t P,
logic [LINELEN-1:0] ReadDataLine, ReadDataLineCache;
logic SelFetchBuffer;
logic CacheEn;
logic SelWay;
logic SelVictim;
logic [LINELEN/8-1:0] LineByteMask;
logic [$clog2(LINELEN/8) - $clog2(MUXINTERVAL/8) - 1:0] WordOffsetAddr;
genvar index;
@ -120,7 +120,7 @@ module cache import cvw::*; #(parameter cvw_t P,
// Array of cache ways, along with victim, hit, dirty, and read merging logic
cacheway #(P, PA_BITS, XLEN, NUMLINES, LINELEN, TAGLEN, OFFSETLEN, SETLEN, READ_ONLY_CACHE) CacheWays[NUMWAYS-1:0](
.clk, .reset, .CacheEn, .CacheSetData, .CacheSetTag, .PAdr, .LineWriteData, .LineByteMask, .SelWay,
.clk, .reset, .CacheEn, .CacheSetData, .CacheSetTag, .PAdr, .LineWriteData, .LineByteMask, .SelVictim,
.SetValid, .ClearValid, .SetDirty, .ClearDirty, .VictimWay,
.FlushWay, .FlushCache, .ReadDataLineWay, .HitWay, .ValidWay, .DirtyWay, .HitDirtyWay, .TagWay, .FlushStage, .InvalidateCache);
@ -132,7 +132,7 @@ module cache import cvw::*; #(parameter cvw_t P,
end else
assign VictimWay = 1'b1; // one hot.
assign CacheHit = |HitWay;
assign Hit = |HitWay;
assign LineDirty = |DirtyWay;
assign HitLineDirty = |HitDirtyWay;
@ -180,14 +180,14 @@ module cache import cvw::*; #(parameter cvw_t P,
assign DemuxedByteMask = BlankByteMask << ((MUXINTERVAL/8) * WordOffsetAddr);
assign FetchBufferByteSel = SetValid & ~SetDirty ? '1 : ~DemuxedByteMask; // If load miss set all muxes to 1.
assign FetchBufferByteSel = SetDirty ? ~DemuxedByteMask : '1; // If load miss set all muxes to 1.
// Merge write data into fetched cache line for store miss
for(index = 0; index < LINELEN/8; index++) begin
mux2 #(8) WriteDataMux(.d0(CacheWriteData[(8*index)%WORDLEN+7:(8*index)%WORDLEN]),
.d1(FetchBuffer[8*index+7:8*index]), .s(FetchBufferByteSel[index] & ~CMOpM[3]), .y(LineWriteData[8*index+7:8*index]));
end
assign LineByteMask = SetValid ? '1 : SetDirty ? DemuxedByteMask : 0;
assign LineByteMask = SetDirty ? DemuxedByteMask : '1;
end
else
begin:WriteSelLogic
@ -226,8 +226,8 @@ module cache import cvw::*; #(parameter cvw_t P,
cachefsm #(P, READ_ONLY_CACHE) cachefsm(.clk, .reset, .CacheBusRW, .CacheBusAck,
.FlushStage, .CacheRW, .Stall,
.CacheHit, .LineDirty, .HitLineDirty, .CacheStall, .CacheCommitted,
.CacheMiss, .CacheAccess, .SelAdrData, .SelAdrTag, .SelWay,
.Hit, .LineDirty, .HitLineDirty, .CacheStall, .CacheCommitted,
.CacheMiss, .CacheAccess, .SelAdrData, .SelAdrTag, .SelVictim,
.ClearDirty, .SetDirty, .SetValid, .ClearValid, .SelWriteback,
.FlushAdrCntEn, .FlushWayCntEn, .FlushCntRst,
.FlushAdrFlag, .FlushWayFlag, .FlushCache, .SelFetchBuffer,

44
src/cache/cacheLRU.sv vendored
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@ -1,7 +1,7 @@
///////////////////////////////////////////
// cacheLRU.sv
//
// Written: Ross Thompson ross1728@gmail.com
// Written: Rose Thompson ross1728@gmail.com
// Created: 20 July 2021
// Modified: 20 January 2023
//
@ -36,8 +36,8 @@ module cacheLRU
input logic CacheEn, // Enable the cache memory arrays. Disable hold read data constant
input logic [NUMWAYS-1:0] HitWay, // Which way is valid and matches PAdr's tag
input logic [NUMWAYS-1:0] ValidWay, // Which ways for a particular set are valid, ignores tag
input logic [SETLEN-1:0] CacheSetData, // Cache address, the output of the address select mux, NextAdr, PAdr, or FlushAdr
input logic [SETLEN-1:0] CacheSetTag, // Cache address, the output of the address select mux, NextAdr, PAdr, or FlushAdr
input logic [SETLEN-1:0] CacheSetData, // Cache address, the output of the address select mux, NextAdr, PAdr, or FlushAdr
input logic [SETLEN-1:0] CacheSetTag, // Cache address, the output of the address select mux, NextAdr, PAdr, or FlushAdr
input logic [SETLEN-1:0] PAdr, // Physical address
input logic LRUWriteEn, // Update the LRU state
input logic SetValid, // Set the dirty bit in the selected way and set
@ -51,23 +51,27 @@ module cacheLRU
logic [NUMWAYS-2:0] LRUMemory [NUMLINES-1:0];
logic [NUMWAYS-2:0] CurrLRU;
logic [NUMWAYS-2:0] NextLRU;
logic [NUMWAYS-1:0] Way;
logic [LOGNUMWAYS-1:0] WayEncoded;
logic [LOGNUMWAYS-1:0] HitWayEncoded, Way;
logic [NUMWAYS-2:0] WayExpanded;
logic AllValid;
genvar row;
/* verilator lint_off UNOPTFLAT */
// Ross: For some reason verilator does not like this. I checked and it is not a circular path.
// Rose: For some reason verilator does not like this. I checked and it is not a circular path.
logic [NUMWAYS-2:0] LRUUpdate;
logic [LOGNUMWAYS-1:0] Intermediate [NUMWAYS-2:0];
/* verilator lint_on UNOPTFLAT */
logic [NUMWAYS-1:0] FirstZero;
logic [LOGNUMWAYS-1:0] FirstZeroWay;
logic [LOGNUMWAYS-1:0] VictimWayEnc;
binencoder #(NUMWAYS) hitwayencoder(HitWay, HitWayEncoded);
assign AllValid = &ValidWay;
///// Update replacement bits.
// coverage off
// Excluded from coverage b/c it is untestable without varying NUMWAYS.
function integer log2 (integer value);
@ -80,8 +84,7 @@ module cacheLRU
// coverage on
// On a miss we need to ignore HitWay and derive the new replacement bits with the VictimWay.
mux2 #(NUMWAYS) WayMux(HitWay, VictimWay, SetValid, Way);
binencoder #(NUMWAYS) encoder(Way, WayEncoded);
mux2 #(LOGNUMWAYS) WayMuxEnc(HitWayEncoded, VictimWayEnc, SetValid, Way);
// bit duplication
// expand HitWay as HitWay[3], {{2}{HitWay[2]}}, {{4}{HitWay[1]}, {{8{HitWay[0]}}, ...
@ -89,7 +92,7 @@ module cacheLRU
localparam integer DuplicationFactor = 2**(LOGNUMWAYS-row-1);
localparam StartIndex = NUMWAYS-2 - DuplicationFactor + 1;
localparam EndIndex = NUMWAYS-2 - 2 * DuplicationFactor + 2;
assign WayExpanded[StartIndex : EndIndex] = {{DuplicationFactor}{WayEncoded[row]}};
assign WayExpanded[StartIndex : EndIndex] = {{DuplicationFactor}{Way[row]}};
end
genvar node;
@ -102,14 +105,14 @@ module cacheLRU
localparam r = LOGNUMWAYS - ctr_depth;
// the child node will be updated if its parent was updated and
// the WayEncoded bit was the correct value.
// the Way bit was the correct value.
// The if statement is only there for coverage since LRUUpdate[root] is always 1.
if (node == NUMWAYS-2) begin
assign LRUUpdate[lchild] = ~WayEncoded[r];
assign LRUUpdate[rchild] = WayEncoded[r];
assign LRUUpdate[lchild] = ~Way[r];
assign LRUUpdate[rchild] = Way[r];
end else begin
assign LRUUpdate[lchild] = LRUUpdate[node] & ~WayEncoded[r];
assign LRUUpdate[rchild] = LRUUpdate[node] & WayEncoded[r];
assign LRUUpdate[lchild] = LRUUpdate[node] & ~Way[r];
assign LRUUpdate[rchild] = LRUUpdate[node] & Way[r];
end
end
@ -129,28 +132,25 @@ module cacheLRU
assign Intermediate[node] = CurrLRU[node] ? int1[LOGNUMWAYS-1:0] : int0[LOGNUMWAYS-1:0];
end
logic [NUMWAYS-1:0] FirstZero;
logic [LOGNUMWAYS-1:0] FirstZeroWay;
logic [LOGNUMWAYS-1:0] VictimWayEnc;
priorityonehot #(NUMWAYS) FirstZeroEncoder(~ValidWay, FirstZero);
binencoder #(NUMWAYS) FirstZeroWayEncoder(FirstZero, FirstZeroWay);
mux2 #(LOGNUMWAYS) VictimMux(FirstZeroWay, Intermediate[NUMWAYS-2], AllValid, VictimWayEnc);
//decoder #(LOGNUMWAYS) decoder (Intermediate[NUMWAYS-2], VictimWay);
decoder #(LOGNUMWAYS) decoder (VictimWayEnc, VictimWay);
// LRU storage must be reset for modelsim to run. However the reset value does not actually matter in practice.
// This is a two port memory.
// Every cycle must read from CacheSetData and each load/store must write the new LRU.
always_ff @(posedge clk) begin
if (reset | (InvalidateCache & ~FlushStage)) for (int set = 0; set < NUMLINES; set++) LRUMemory[set] <= 0;
if (reset | (InvalidateCache & ~FlushStage))
for (int set = 0; set < NUMLINES; set++) LRUMemory[set] <= 0; // exclusion-tag: initialize
if(CacheEn) begin
if(LRUWriteEn)
LRUMemory[PAdr] <= NextLRU;
if(LRUWriteEn & (PAdr == CacheSetTag))
CurrLRU <= NextLRU;
CurrLRU <= #1 NextLRU;
else
CurrLRU <= LRUMemory[CacheSetTag];
CurrLRU <= #1 LRUMemory[CacheSetTag];
end
end

76
src/cache/cachefsm.sv vendored
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@ -50,7 +50,7 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
output logic CacheAccess, // Cache access
// cache internals
input logic CacheHit, // Exactly 1 way hits
input logic Hit, // Exactly 1 way hits
input logic LineDirty, // The selected line and way is dirty
input logic HitLineDirty, // The cache hit way is dirty
input logic FlushAdrFlag, // On last set of a cache flush
@ -63,7 +63,7 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
output logic ClearDirty, // Clear the dirty bit in the selected way and set
output logic SelWriteback, // Overrides cached tag check to select a specific way and set for writeback
output logic LRUWriteEn, // Update the LRU state
output logic SelWay, // Controls which way to select a way data and tag, 00 = hitway, 10 = victimway, 11 = flushway
output logic SelVictim, // Overides HitWay Tag matching. Selects selects the victim tag/data regardless of hit
output logic FlushAdrCntEn, // Enable the counter for Flush Adr
output logic FlushWayCntEn, // Enable the way counter during a flush
output logic FlushCntRst, // Reset both flush counters
@ -79,12 +79,12 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
logic CMOZeroNoEviction;
logic StallConditions;
typedef enum logic [3:0]{STATE_READY, // hit states
typedef enum logic [3:0]{STATE_ACCESS, // hit states
// miss states
STATE_FETCH,
STATE_WRITEBACK,
STATE_WRITE_LINE,
STATE_READ_HOLD, // required for back to back reads. structural hazard on writting SRAM
STATE_ADDRESS_SETUP, // required for back to back reads. structural hazard on writting SRAM
// flush cache
STATE_FLUSH,
STATE_FLUSH_WRITEBACK
@ -92,60 +92,60 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
statetype CurrState, NextState;
assign AnyMiss = (CacheRW[0] | CacheRW[1]) & ~CacheHit & ~InvalidateCache; // exclusion-tag: cache AnyMiss
assign AnyUpdateHit = (CacheRW[0]) & CacheHit; // exclusion-tag: icache storeAMO1
assign AnyHit = AnyUpdateHit | (CacheRW[1] & CacheHit); // exclusion-tag: icache AnyUpdateHit
assign AnyMiss = (CacheRW[0] | CacheRW[1]) & ~Hit & ~InvalidateCache; // exclusion-tag: cache AnyMiss
assign AnyUpdateHit = (CacheRW[0]) & Hit; // exclusion-tag: icache storeAMO1
assign AnyHit = AnyUpdateHit | (CacheRW[1] & Hit); // exclusion-tag: icache AnyUpdateHit
assign CMOZeroNoEviction = CMOpM[3] & ~LineDirty; // (hit or miss) with no writeback store zeros now
assign CMOWriteback = ((CMOpM[1] | CMOpM[2]) & CacheHit & HitLineDirty) | CMOpM[3] & LineDirty;
assign CMOWriteback = ((CMOpM[1] | CMOpM[2]) & Hit & HitLineDirty) | CMOpM[3] & LineDirty;
assign FlushFlag = FlushAdrFlag & FlushWayFlag;
// outputs for the performance counters.
assign CacheAccess = (|CacheRW) & ((CurrState == STATE_READY & ~Stall & ~FlushStage) | (CurrState == STATE_READ_HOLD & ~Stall & ~FlushStage)); // exclusion-tag: icache CacheW
assign CacheMiss = CacheAccess & ~CacheHit;
assign CacheAccess = (|CacheRW) & ((CurrState == STATE_ACCESS & ~Stall & ~FlushStage) | (CurrState == STATE_ADDRESS_SETUP & ~Stall & ~FlushStage)); // exclusion-tag: icache CacheW
assign CacheMiss = CacheAccess & ~Hit;
// special case on reset. When the fsm first exists reset the
// special case on reset. When the fsm first exists reset twayhe
// PCNextF will no longer be pointing to the correct address.
// But PCF will be the reset vector.
flop #(1) resetDelayReg(.clk, .d(reset), .q(resetDelay));
always_ff @(posedge clk)
if (reset | FlushStage) CurrState <= #1 STATE_READY;
if (reset | FlushStage) CurrState <= #1 STATE_ACCESS;
else CurrState <= #1 NextState;
always_comb begin
NextState = STATE_READY;
NextState = STATE_ACCESS;
case (CurrState) // exclusion-tag: icache state-case
STATE_READY: if(InvalidateCache) NextState = STATE_READY; // exclusion-tag: dcache InvalidateCheck
STATE_ACCESS: if(InvalidateCache) NextState = STATE_ACCESS; // exclusion-tag: dcache InvalidateCheck
else if(FlushCache & ~READ_ONLY_CACHE) NextState = STATE_FLUSH; // exclusion-tag: icache FLUSHStatement
else if(AnyMiss & (READ_ONLY_CACHE | ~LineDirty)) NextState = STATE_FETCH; // exclusion-tag: icache FETCHStatement
else if((AnyMiss | CMOWriteback) & ~READ_ONLY_CACHE) NextState = STATE_WRITEBACK; // exclusion-tag: icache WRITEBACKStatement
else NextState = STATE_READY;
else NextState = STATE_ACCESS;
STATE_FETCH: if(CacheBusAck) NextState = STATE_WRITE_LINE;
else NextState = STATE_FETCH;
STATE_WRITE_LINE: NextState = STATE_READ_HOLD;
STATE_READ_HOLD: if(Stall) NextState = STATE_READ_HOLD;
else NextState = STATE_READY;
STATE_WRITE_LINE: NextState = STATE_ADDRESS_SETUP;
STATE_ADDRESS_SETUP: if(Stall) NextState = STATE_ADDRESS_SETUP;
else NextState = STATE_ACCESS;
// exclusion-tag-start: icache case
STATE_WRITEBACK: if(CacheBusAck & ~(|CMOpM[3:1])) NextState = STATE_FETCH;
else if(CacheBusAck) NextState = STATE_READ_HOLD; // Read_hold lowers CacheStall
else if(CacheBusAck) NextState = STATE_ADDRESS_SETUP; // Read_hold lowers CacheStall
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.
STATE_FLUSH: if(LineDirty) NextState = STATE_FLUSH_WRITEBACK;
else if (FlushFlag) NextState = STATE_READ_HOLD;
else if (FlushFlag) NextState = STATE_ADDRESS_SETUP;
else NextState = STATE_FLUSH;
STATE_FLUSH_WRITEBACK: if(CacheBusAck & ~FlushFlag) NextState = STATE_FLUSH;
else if(CacheBusAck) NextState = STATE_READ_HOLD;
else if(CacheBusAck) NextState = STATE_ADDRESS_SETUP;
else NextState = STATE_FLUSH_WRITEBACK;
// exclusion-tag-end: icache case
default: NextState = STATE_READY;
default: NextState = STATE_ACCESS;
endcase
end
// com back to CPU
assign CacheCommitted = (CurrState != STATE_READY) & ~(READ_ONLY_CACHE & (CurrState == STATE_READ_HOLD));
assign CacheCommitted = (CurrState != STATE_ACCESS) & ~(READ_ONLY_CACHE & (CurrState == STATE_ADDRESS_SETUP));
assign StallConditions = FlushCache | AnyMiss | CMOWriteback; // exclusion-tag: icache FlushCache
assign CacheStall = (CurrState == STATE_READY & StallConditions) | // exclusion-tag: icache StallStates
assign CacheStall = (CurrState == STATE_ACCESS & StallConditions) | // exclusion-tag: icache StallStates
(CurrState == STATE_FETCH) |
(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.
@ -153,26 +153,26 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
(CurrState == STATE_FLUSH_WRITEBACK);
// write enables internal to cache
assign SetValid = CurrState == STATE_WRITE_LINE |
(CurrState == STATE_READY & CMOZeroNoEviction) |
(CurrState == STATE_ACCESS & CMOZeroNoEviction) |
(CurrState == STATE_WRITEBACK & CacheBusAck & CMOpM[3]);
assign ClearValid = (CurrState == STATE_READY & CMOpM[0]) |
assign ClearValid = (CurrState == STATE_ACCESS & CMOpM[0]) |
(CurrState == STATE_WRITEBACK & CMOpM[2] & CacheBusAck);
assign LRUWriteEn = (((CurrState == STATE_READY & (AnyHit | CMOZeroNoEviction)) |
assign LRUWriteEn = (((CurrState == STATE_ACCESS & (AnyHit | CMOZeroNoEviction)) |
(CurrState == STATE_WRITE_LINE)) & ~FlushStage) |
(CurrState == STATE_WRITEBACK & CMOpM[3] & CacheBusAck);
// exclusion-tag-start: icache flushdirtycontrols
assign SetDirty = (CurrState == STATE_READY & (AnyUpdateHit | CMOZeroNoEviction)) | // exclusion-tag: icache SetDirty
assign SetDirty = (CurrState == STATE_ACCESS & (AnyUpdateHit | CMOZeroNoEviction)) | // exclusion-tag: icache SetDirty
(CurrState == STATE_WRITE_LINE & (CacheRW[0])) |
(CurrState == STATE_WRITEBACK & (CMOpM[3] & CacheBusAck));
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.
// Flush and eviction controls
CurrState == STATE_WRITEBACK & (CMOpM[1] | CMOpM[2]) & CacheBusAck;
assign SelWay = (CurrState == STATE_WRITEBACK & ((~CacheBusAck & ~(CMOpM[1] | CMOpM[2])) | (CacheBusAck & CMOpM[3]))) |
(CurrState == STATE_READY & ((AnyMiss & LineDirty) | (CMOZeroNoEviction & ~CacheHit))) |
assign SelVictim = (CurrState == STATE_WRITEBACK & ((~CacheBusAck & ~(CMOpM[1] | CMOpM[2])) | (CacheBusAck & CMOpM[3]))) |
(CurrState == STATE_ACCESS & ((AnyMiss & LineDirty) | (CMOZeroNoEviction & ~Hit))) |
(CurrState == STATE_WRITE_LINE);
assign SelWriteback = (CurrState == STATE_WRITEBACK & (CMOpM[1] | CMOpM[2] | ~CacheBusAck)) |
(CurrState == STATE_READY & AnyMiss & LineDirty);
(CurrState == STATE_ACCESS & AnyMiss & LineDirty);
// coverage off -item e 1 -fecexprrow 1
// (state is always FLUSH_WRITEBACK when FlushWayFlag & CacheBusAck)
assign FlushAdrCntEn = (CurrState == STATE_FLUSH_WRITEBACK & FlushWayFlag & CacheBusAck) |
@ -183,29 +183,29 @@ module cachefsm import cvw::*; #(parameter cvw_t P,
(CurrState == STATE_FLUSH_WRITEBACK & FlushFlag & CacheBusAck);
// exclusion-tag-end: icache flushdirtycontrols
// Bus interface controls
assign CacheBusRW[1] = (CurrState == STATE_READY & AnyMiss & ~LineDirty) | // exclusion-tag: icache CacheBusRCauses
assign CacheBusRW[1] = (CurrState == STATE_ACCESS & AnyMiss & ~LineDirty) | // exclusion-tag: icache CacheBusRCauses
(CurrState == STATE_FETCH & ~CacheBusAck) |
(CurrState == STATE_WRITEBACK & CacheBusAck & ~(|CMOpM));
logic LoadMiss;
assign LoadMiss = (CacheRW[1]) & ~CacheHit & ~InvalidateCache; // exclusion-tag: cache AnyMiss
assign LoadMiss = (CacheRW[1]) & ~Hit & ~InvalidateCache; // exclusion-tag: cache AnyMiss
assign CacheBusRW[0] = (CurrState == STATE_READY & LoadMiss & LineDirty) | // exclusion-tag: icache CacheBusW
assign CacheBusRW[0] = (CurrState == STATE_ACCESS & LoadMiss & LineDirty) | // exclusion-tag: icache CacheBusW
(CurrState == STATE_WRITEBACK & ~CacheBusAck) |
(CurrState == STATE_FLUSH_WRITEBACK & ~CacheBusAck) |
(CurrState == STATE_WRITEBACK & (CMOpM[1] | CMOpM[2]) & ~CacheBusAck);
assign SelAdrData = (CurrState == STATE_READY & (CacheRW[0] | AnyMiss | (|CMOpM))) | // exclusion-tag: icache SelAdrCauses // changes if store delay hazard removed
assign SelAdrData = (CurrState == STATE_ACCESS & (CacheRW[0] | AnyMiss | (|CMOpM))) | // exclusion-tag: icache SelAdrCauses // changes if store delay hazard removed
(CurrState == STATE_FETCH) |
(CurrState == STATE_WRITEBACK) |
(CurrState == STATE_WRITE_LINE) |
resetDelay;
assign SelAdrTag = (CurrState == STATE_READY & (AnyMiss | (|CMOpM))) | // exclusion-tag: icache SelAdrTag // changes if store delay hazard removed
assign SelAdrTag = (CurrState == STATE_ACCESS & (AnyMiss | (|CMOpM))) | // exclusion-tag: icache SelAdrTag // changes if store delay hazard removed
(CurrState == STATE_FETCH) |
(CurrState == STATE_WRITEBACK) |
(CurrState == STATE_WRITE_LINE) |
resetDelay;
assign SelFetchBuffer = CurrState == STATE_WRITE_LINE | CurrState == STATE_READ_HOLD;
assign CacheEn = (~Stall | StallConditions) | (CurrState != STATE_READY) | reset | InvalidateCache; // exclusion-tag: dcache CacheEn
assign SelFetchBuffer = CurrState == STATE_WRITE_LINE | CurrState == STATE_ADDRESS_SETUP;
assign CacheEn = (~Stall | StallConditions) | (CurrState != STATE_ACCESS) | reset | InvalidateCache; // exclusion-tag: dcache CacheEn
endmodule // cachefsm

33
src/cache/cacheway.sv vendored
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@ -42,7 +42,7 @@ module cacheway import cvw::*; #(parameter cvw_t P,
input logic SetValid, // Set the valid bit in the selected way and set
input logic ClearValid, // Clear the valid bit in the selected way and set
input logic SetDirty, // Set the dirty bit in the selected way and set
input logic SelWay, // Controls which way to select a way data and tag, 00 = hitway, 10 = victimway, 11 = flushway
input logic SelVictim, // Overides HitWay Tag matching. Selects selects the victim tag/data regardless of hit
input logic ClearDirty, // Clear the dirty bit in the selected way and set
input logic FlushCache, // [0] Use SelAdr, [1] SRAM reads/writes from FlushAdr
input logic VictimWay, // LRU selected this way as victim to evict
@ -68,7 +68,7 @@ module cacheway import cvw::*; #(parameter cvw_t P,
logic [LINELEN-1:0] ReadDataLine;
logic [TAGLEN-1:0] ReadTag;
logic Dirty;
logic SelDirty;
logic SelecteDirty;
logic SelectedWriteWordEn;
logic [LINELEN/8-1:0] FinalByteMask;
logic SetValidEN, ClearValidEN;
@ -77,33 +77,30 @@ module cacheway import cvw::*; #(parameter cvw_t P,
logic SetDirtyWay;
logic ClearDirtyWay;
logic SelNonHit;
logic SelData;
logic SelectedWay;
logic InvalidateCacheDelay;
if (!READ_ONLY_CACHE) begin:flushlogic
logic FlushWayEn;
mux2 #(1) seltagmux(VictimWay, FlushWay, FlushCache, SelDirty);
mux2 #(1) seltagmux(VictimWay, FlushWay, FlushCache, SelecteDirty);
mux3 #(1) selectedmux(HitWay, FlushWay, VictimWay, {SelVictim, FlushCache}, SelectedWay);
// FlushWay is part of a one hot way selection. Must clear it if FlushWay not selected.
// coverage off -item e 1 -fecexprrow 3
// nonzero ways will never see FlushCache=0 while FlushWay=1 since FlushWay only advances on a subset of FlushCache assertion cases.
assign FlushWayEn = FlushWay & FlushCache;
assign SelNonHit = FlushWayEn | SelWay;
end else begin:flushlogic // no flush operation for read-only caches.
assign SelDirty = VictimWay;
assign SelNonHit = SelWay;
assign SelecteDirty = VictimWay;
mux2 #(1) selectedwaymux(HitWay, SelecteDirty, SelVictim , SelectedWay);
end
mux2 #(1) selectedwaymux(HitWay, SelDirty, SelNonHit , SelData);
/////////////////////////////////////////////////////////////////////////////////////////////
// Write Enable demux
/////////////////////////////////////////////////////////////////////////////////////////////
assign SetValidWay = SetValid & SelData;
assign ClearValidWay = ClearValid & SelData; // exclusion-tag: icache ClearValidWay
assign SetDirtyWay = SetDirty & SelData; // exclusion-tag: icache SetDirtyWay
assign ClearDirtyWay = ClearDirty & SelData;
assign SetValidWay = SetValid & SelectedWay;
assign ClearValidWay = ClearValid & SelectedWay; // exclusion-tag: icache ClearValidWay
assign SetDirtyWay = SetDirty & SelectedWay; // exclusion-tag: icache SetDirtyWay
assign ClearDirtyWay = ClearDirty & SelectedWay;
assign SelectedWriteWordEn = (SetValidWay | SetDirtyWay) & ~FlushStage; // exclusion-tag: icache SelectedWiteWordEn
assign SetValidEN = SetValidWay & ~FlushStage; // exclusion-tag: cache SetValidEN
assign ClearValidEN = ClearValidWay & ~FlushStage; // exclusion-tag: cache ClearValidEN
@ -120,9 +117,9 @@ module cacheway import cvw::*; #(parameter cvw_t P,
.din(PAdr[PA_BITS-1:OFFSETLEN+INDEXLEN]), .we(SetValidEN));
// AND portion of distributed tag multiplexer
assign TagWay = SelData ? ReadTag : 0; // AND part of AOMux
assign TagWay = SelectedWay ? ReadTag : 0; // AND part of AOMux
assign HitDirtyWay = Dirty & ValidWay;
assign DirtyWay = SelDirty & HitDirtyWay; // exclusion-tag: icache DirtyWay
assign DirtyWay = SelecteDirty & HitDirtyWay; // exclusion-tag: icache DirtyWay
assign HitWay = ValidWay & (ReadTag == PAdr[PA_BITS-1:OFFSETLEN+INDEXLEN]) & ~InvalidateCacheDelay; // exclusion-tag: dcache HitWay
flop #(1) InvalidateCacheReg(clk, InvalidateCache, InvalidateCacheDelay);
@ -152,7 +149,7 @@ module cacheway import cvw::*; #(parameter cvw_t P,
end
// AND portion of distributed read multiplexers
assign ReadDataLineWay = SelData ? ReadDataLine : 0; // AND part of AO mux.
assign ReadDataLineWay = SelectedWay ? ReadDataLine : 0; // AND part of AO mux.
/////////////////////////////////////////////////////////////////////////////////////////////
// Valid Bits

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@ -37,6 +37,7 @@ module align import cvw::*; #(parameter cvw_t P) (
input logic [P.XLEN-1:0] IEUAdrM, // 2 byte aligned PC in Fetch stage
input logic [P.XLEN-1:0] IEUAdrE, // The next IEUAdrM
input logic [2:0] Funct3M, // Size of memory operation
input logic FpLoadStoreM, // Floating point Load or Store
input logic [1:0] MemRWM,
input logic [P.LLEN*2-1:0] DCacheReadDataWordM, // Instruction from the IROM, I$, or bus. Used to check if the instruction if compressed
input logic CacheBusHPWTStall, // I$ or bus are stalled. Transition to second fetch of spill after the first is fetched
@ -52,7 +53,6 @@ module align import cvw::*; #(parameter cvw_t P) (
output logic [P.XLEN-1:0] IEUAdrSpillE, // The next PCF for one of the two memory addresses of the spill
output logic [P.XLEN-1:0] IEUAdrSpillM, // IEUAdrM for one of the two memory addresses of the spill
output logic SelSpillE, // During the transition between the two spill operations, the IFU should stall the pipeline
output logic SelStoreDelay, //*** this is bad. really don't like moving this outside
output logic [P.LLEN-1:0] DCacheReadDataWordSpillM, // The final 32 bit instruction after merging the two spilled fetches into 1 instruction
output logic SpillStallM);
@ -72,6 +72,7 @@ module align import cvw::*; #(parameter cvw_t P) (
logic [P.XLEN-1:0] IEUAdrIncrementM;
localparam OFFSET_LEN = $clog2(LLENINBYTES);
logic [$clog2(LLENINBYTES)-1:0] AccessByteOffsetM;
logic [$clog2(LLENINBYTES)+2:0] ShiftAmount;
logic PotentialSpillM;
@ -93,12 +94,15 @@ module align import cvw::*; #(parameter cvw_t P) (
// compute misalignement
always_comb begin
case (Funct3M[1:0])
2'b00: AccessByteOffsetM = 0; // byte access
2'b01: AccessByteOffsetM = {2'b00, IEUAdrM[0]}; // half access
2'b10: AccessByteOffsetM = {1'b0, IEUAdrM[1:0]}; // word access
2'b11: AccessByteOffsetM = IEUAdrM[2:0]; // double access
default: AccessByteOffsetM = IEUAdrM[2:0];
case (Funct3M & {FpLoadStoreM, 2'b11})
3'b000: AccessByteOffsetM = 0; // byte access
3'b001: AccessByteOffsetM = {{OFFSET_LEN-1{1'b0}}, IEUAdrM[0]}; // half access
3'b010: AccessByteOffsetM = {{OFFSET_LEN-2{1'b0}}, IEUAdrM[1:0]}; // word access
3'b011: if(P.LLEN >= 64) AccessByteOffsetM = {{OFFSET_LEN-3{1'b0}}, IEUAdrM[2:0]}; // double access
else AccessByteOffsetM = 0; // shouldn't happen
3'b100: if(P.LLEN == 128) AccessByteOffsetM = IEUAdrM[OFFSET_LEN-1:0]; // quad access
else AccessByteOffsetM = IEUAdrM[OFFSET_LEN-1:0];
default: AccessByteOffsetM = 0; // shouldn't happen
endcase
case (Funct3M[1:0])
2'b00: PotentialSpillM = 0; // byte access
@ -118,20 +122,17 @@ module align import cvw::*; #(parameter cvw_t P) (
always_comb begin
case (CurrState)
STATE_READY: if (ValidSpillM & ~MemRWM[0]) NextState = STATE_SPILL; // load spill
else if(ValidSpillM) NextState = STATE_STORE_DELAY; // store spill
STATE_READY: if (ValidSpillM) NextState = STATE_SPILL; // load spill
else NextState = STATE_READY; // no spill
STATE_SPILL: if(StallM) NextState = STATE_SPILL;
else NextState = STATE_READY;
STATE_STORE_DELAY: NextState = STATE_SPILL;
default: NextState = STATE_READY;
endcase
end
assign SelSpillM = (CurrState == STATE_SPILL | CurrState == STATE_STORE_DELAY);
assign SelSpillE = (CurrState == STATE_READY & ValidSpillM) | (CurrState == STATE_SPILL & CacheBusHPWTStall) | (CurrState == STATE_STORE_DELAY);
assign SelSpillM = CurrState == STATE_SPILL;
assign SelSpillE = (CurrState == STATE_READY & ValidSpillM) | (CurrState == STATE_SPILL & CacheBusHPWTStall);
assign SpillSaveM = (CurrState == STATE_READY) & ValidSpillM & ~FlushM;
assign SelStoreDelay = (CurrState == STATE_STORE_DELAY); // *** Can this be merged into the PreLSURWM logic?
assign SpillStallM = SelSpillE;
////////////////////////////////////////////////////////////////////////////////////////////////////

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@ -143,7 +143,6 @@ module lsu import cvw::*; #(parameter cvw_t P) (
logic [(P.LLEN-1)/8:0] ByteMaskExtendedM; // Selects which bytes within a word to write
logic [1:0] MemRWSpillM;
logic SpillStallM;
logic SelStoreDelay;
logic DTLBMissM; // DTLB miss causes HPTW walk
logic DTLBWriteM; // Writes PTE and PageType to DTLB
@ -164,12 +163,11 @@ module lsu import cvw::*; #(parameter cvw_t P) (
flopenrc #(P.XLEN) AddressMReg(clk, reset, FlushM, ~StallM, IEUAdrE, IEUAdrM);
if(MISALIGN_SUPPORT) begin : ziccslm_align
logic [P.XLEN-1:0] IEUAdrSpillE, IEUAdrSpillM;
align #(P) align(.clk, .reset, .StallM, .FlushM, .IEUAdrE, .IEUAdrM, .Funct3M,
align #(P) align(.clk, .reset, .StallM, .FlushM, .IEUAdrE, .IEUAdrM, .Funct3M, .FpLoadStoreM,
.MemRWM,
.DCacheReadDataWordM, .CacheBusHPWTStall, .SelHPTW,
.ByteMaskM, .ByteMaskExtendedM, .LSUWriteDataM, .ByteMaskSpillM, .LSUWriteDataSpillM,
.IEUAdrSpillE, .IEUAdrSpillM, .SelSpillE, .DCacheReadDataWordSpillM, .SpillStallM,
.SelStoreDelay);
.IEUAdrSpillE, .IEUAdrSpillM, .SelSpillE, .DCacheReadDataWordSpillM, .SpillStallM);
assign IEUAdrExtM = {2'b00, IEUAdrSpillM};
assign IEUAdrExtE = {2'b00, IEUAdrSpillE};
end else begin : no_ziccslm_align
@ -180,7 +178,7 @@ module lsu import cvw::*; #(parameter cvw_t P) (
assign ByteMaskSpillM = ByteMaskM;
assign LSUWriteDataSpillM = LSUWriteDataM;
assign MemRWSpillM = MemRWM;
assign {SpillStallM, SelStoreDelay} = 0;
assign {SpillStallM} = 0;
end
if(P.ZICBOZ_SUPPORTED) begin : cboz
@ -333,7 +331,7 @@ module lsu import cvw::*; #(parameter cvw_t P) (
cache #(.P(P), .PA_BITS(P.PA_BITS), .XLEN(P.XLEN), .LINELEN(P.DCACHE_LINELENINBITS), .NUMLINES(P.DCACHE_WAYSIZEINBYTES*8/LINELEN),
.NUMWAYS(P.DCACHE_NUMWAYS), .LOGBWPL(LLENLOGBWPL), .WORDLEN(CACHEWORDLEN), .MUXINTERVAL(P.LLEN), .READ_ONLY_CACHE(0)) dcache(
.clk, .reset, .Stall(GatedStallW & ~SelSpillE), .SelBusBeat, .FlushStage(FlushW | IgnoreRequestTLB),
.CacheRW(SelStoreDelay ? 2'b00 : CacheRWM),
.CacheRW(CacheRWM),
.FlushCache(FlushDCache), .NextSet(IEUAdrExtE[11:0]), .PAdr(PAdrM),
.ByteMask(ByteMaskSpillM), .BeatCount(BeatCount[AHBWLOGBWPL-1:AHBWLOGBWPL-LLENLOGBWPL]),
.CacheWriteData(LSUWriteDataSpillM), .SelHPTW,

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@ -80,7 +80,7 @@ module privdec import cvw::*; #(parameter cvw_t P) (
if (P.U_SUPPORTED) begin:wfi
logic [P.WFI_TIMEOUT_BIT:0] WFICount, WFICountPlus1;
assign WFICountPlus1 = wfiM ? 0 : WFICount + 1; // restart counting on WFI
assign WFICountPlus1 = wfiM ? WFICount + 1 : '0; // restart counting on WFI
flopr #(P.WFI_TIMEOUT_BIT+1) wficountreg(clk, reset, WFICountPlus1, WFICount); // count while in WFI
// coverage off -item e 1 -fecexprrow 1
// WFI Timout trap will not occur when STATUS_TW is low while in supervisor mode, so the system gets stuck waiting for an interrupt and triggers a watchdog timeout.