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Removed CommittedM as it is redundant with LSUStall.

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This commit is contained in:
Ross Thompson 2021-12-28 16:14:10 -06:00
parent 39bd78c295
commit e29803be30
6 changed files with 8 additions and 39 deletions
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2
wally-pipelined/src/cache/dcache.sv vendored
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@ -42,7 +42,6 @@ module dcache
input logic [`XLEN-1:0] FinalWriteDataM,
output logic [`XLEN-1:0] ReadDataWordM,
output logic DCacheStall,
output logic CommittedM,
output logic DCacheMiss,
output logic DCacheAccess,
@ -282,7 +281,6 @@ module dcache
.CacheHit,
.VictimDirty,
.DCacheStall,
.CommittedM,
.DCacheMiss,
.DCacheAccess,
.SelAdrM,

15
wally-pipelined/src/cache/dcachefsm.sv vendored
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@ -46,7 +46,6 @@ module dcachefsm
// hazard outputs
output logic DCacheStall,
output logic CommittedM,
// counter outputs
output logic DCacheMiss,
output logic DCacheAccess,
@ -115,7 +114,6 @@ module dcachefsm
ClearDirty = 1'b0;
SRAMWordWriteEnableM = 1'b0;
SRAMBlockWriteEnableM = 1'b0;
CommittedM = 1'b0;
SelEvict = 1'b0;
LRUWriteEn = 1'b0;
SelFlush = 1'b0;
@ -136,7 +134,6 @@ module dcachefsm
SRAMWordWriteEnableM = 1'b0;
SetDirty = 1'b0;
LRUWriteEn = 1'b0;
CommittedM = 1'b0;
// TLB Miss
if(IgnoreRequest) begin
@ -146,7 +143,6 @@ module dcachefsm
// PTW ready the CPU will stall.
// The page table walker asserts it's control 1 cycle
// after the TLBs miss.
// CommittedM = 1'b1; ??? *** Not Sure yet.
NextState = STATE_READY;
end
@ -216,7 +212,6 @@ module dcachefsm
STATE_MISS_FETCH_WDV: begin
DCacheStall = 1'b1;
SelAdrM = 2'b10;
CommittedM = 1'b1;
if (BUSACK) begin
NextState = STATE_MISS_FETCH_DONE;
@ -228,7 +223,6 @@ module dcachefsm
STATE_MISS_FETCH_DONE: begin
DCacheStall = 1'b1;
SelAdrM = 2'b10;
CommittedM = 1'b1;
if(VictimDirty) begin
NextState = STATE_MISS_EVICT_DIRTY;
DCWriteLine = 1'b1;
@ -244,14 +238,12 @@ module dcachefsm
SelAdrM = 2'b10;
SetValid = 1'b1;
ClearDirty = 1'b1;
CommittedM = 1'b1;
//LRUWriteEn = 1'b1; // DO not update LRU on SRAM fetch update. Wait for subsequent read/write
end
STATE_MISS_READ_WORD: begin
SelAdrM = 2'b10;
DCacheStall = 1'b1;
CommittedM = 1'b1;
if (MemRWM[0] & ~AtomicM[1]) begin // handles stores and amo write.
NextState = STATE_MISS_WRITE_WORD;
end else begin
@ -263,7 +255,6 @@ module dcachefsm
STATE_MISS_READ_WORD_DELAY: begin
//SelAdrM = 2'b10;
CommittedM = 1'b1;
SRAMWordWriteEnableM = 1'b0;
SetDirty = 1'b0;
LRUWriteEn = 1'b0;
@ -294,7 +285,6 @@ module dcachefsm
SRAMWordWriteEnableM = 1'b1;
SetDirty = 1'b1;
SelAdrM = 2'b10;
CommittedM = 1'b1;
LRUWriteEn = 1'b1;
if(CPUBusy) begin
NextState = STATE_CPU_BUSY;
@ -308,7 +298,6 @@ module dcachefsm
STATE_MISS_EVICT_DIRTY: begin
DCacheStall = 1'b1;
SelAdrM = 2'b10;
CommittedM = 1'b1;
SelEvict = 1'b1;
if(BUSACK) begin
NextState = STATE_MISS_WRITE_CACHE_BLOCK;
@ -319,7 +308,6 @@ module dcachefsm
STATE_CPU_BUSY: begin
CommittedM = 1'b1;
SelAdrM = 2'b00;
if(CPUBusy) begin
NextState = STATE_CPU_BUSY;
@ -331,7 +319,6 @@ module dcachefsm
end
STATE_CPU_BUSY_FINISH_AMO: begin
CommittedM = 1'b1;
SelAdrM = 2'b10;
SRAMWordWriteEnableM = 1'b0;
SetDirty = 1'b0;
@ -349,7 +336,6 @@ module dcachefsm
STATE_FLUSH: begin
DCacheStall = 1'b1;
CommittedM = 1'b1;
SelAdrM = 2'b11;
SelFlush = 1'b1;
FlushAdrCntEn = 1'b1;
@ -372,7 +358,6 @@ module dcachefsm
STATE_FLUSH_WRITE_BACK: begin
DCacheStall = 1'b1;
SelAdrM = 2'b11;
CommittedM = 1'b1;
SelFlush = 1'b1;
if(BUSACK) begin
NextState = STATE_FLUSH_CLEAR_DIRTY;

15
wally-pipelined/src/lsu/lsu.sv
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@ -42,7 +42,6 @@ module lsu
input logic ExceptionM,
input logic PendingInterruptM,
input logic FlushDCacheM,
output logic CommittedM,
output logic SquashSCW,
output logic DCacheMiss,
output logic DCacheAccess,
@ -110,9 +109,6 @@ module lsu
logic SelHPTW;
logic DCCommittedM;
logic CommittedMfromBus;
logic BusStall;
@ -221,7 +217,6 @@ module lsu
assign CPUBusy = StallW & ~SelHPTW;
// always block interrupts when using the hardware page table walker.
assign CommittedM = SelHPTW | DCCommittedM | CommittedMfromBus;
// this is for the d cache SRAM.
// turns out because we cannot pipeline hptw requests we don't need this register
@ -259,13 +254,13 @@ module lsu
assign LsuAdrE = IEUAdrE[11:0];
assign LsuPAdrM = IEUAdrExtM;
assign CPUBusy = StallW;
assign CommittedM = CommittedMfromBus;
assign DTLBLoadPageFaultM = 1'b0;
assign DTLBStorePageFaultM = 1'b0;
end
endgenerate
mmu #(.TLB_ENTRIES(`DTLB_ENTRIES), .IMMU(0))
dmmu(.clk, .reset, .SATP_REGW, .STATUS_MXR, .STATUS_SUM, .STATUS_MPRV, .STATUS_MPP,
.PrivilegeModeW, .DisableTranslation(SelHPTW),
@ -369,7 +364,6 @@ module lsu
.MemAdrE(DCAdrE),
.MemPAdrM,
.FinalWriteDataM, .ReadDataWordM, .DCacheStall,
.CommittedM(DCCommittedM),
.DCacheMiss, .DCacheAccess, .IgnoreRequest,
.CacheableM(CacheableM),
@ -475,7 +469,6 @@ module lsu
PreCntEn = 1'b0;
LsuBusWrite = 1'b0;
LsuBusRead = 1'b0;
CommittedMfromBus = 1'b0;
BUSACK = 1'b0;
SelUncached = 1'b0;
@ -515,7 +508,6 @@ module lsu
STATE_BUS_UNCACHED_WRITE : begin
BusStall = 1'b1;
LsuBusWrite = 1'b1;
CommittedMfromBus = 1'b1;
if(LsuBusAck) begin
BusNextState = STATE_BUS_UNCACHED_WRITE_DONE;
end else begin
@ -526,7 +518,6 @@ module lsu
STATE_BUS_UNCACHED_READ: begin
BusStall = 1'b1;
LsuBusRead = 1'b1;
CommittedMfromBus = 1'b1;
if(LsuBusAck) begin
BusNextState = STATE_BUS_UNCACHED_READ_DONE;
end else begin
@ -535,12 +526,10 @@ module lsu
end
STATE_BUS_UNCACHED_WRITE_DONE: begin
CommittedMfromBus = 1'b1;
BusNextState = STATE_BUS_READY;
end
STATE_BUS_UNCACHED_READ_DONE: begin
CommittedMfromBus = 1'b1;
SelUncached = 1'b1;
end
@ -548,7 +537,6 @@ module lsu
BusStall = 1'b1;
PreCntEn = 1'b1;
LsuBusRead = 1'b1;
CommittedMfromBus = 1'b1;
if (FetchCountFlag & LsuBusAck) begin
BusNextState = STATE_BUS_READY;
@ -562,7 +550,6 @@ module lsu
BusStall = 1'b1;
PreCntEn = 1'b1;
LsuBusWrite = 1'b1;
CommittedMfromBus = 1'b1;
if(FetchCountFlag & LsuBusAck) begin
BusNextState = STATE_BUS_READY;
BUSACK = 1'b1;

4
wally-pipelined/src/privileged/privileged.sv
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@ -39,7 +39,7 @@ module privileged (
output logic [`XLEN-1:0] PrivilegedNextPCM,
output logic RetM, TrapM,
output logic ITLBFlushF, DTLBFlushM,
input logic InstrValidM, CommittedM,
input logic InstrValidM, LSUStall,
input logic FRegWriteM, LoadStallD,
input logic BPPredDirWrongM,
input logic BTBPredPCWrongM,
@ -230,7 +230,7 @@ module privileged (
.PCM,
.InstrMisalignedAdrM, .IEUAdrM,
.InstrM,
.InstrValidM, .CommittedM,
.InstrValidM, .LSUStall,
.TrapM, .MTrapM, .STrapM, .UTrapM, .RetM,
.InterruptM,
.ExceptionM,

6
wally-pipelined/src/privileged/trap.sv
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@ -41,7 +41,7 @@ module trap (
input logic [`XLEN-1:0] PCM,
input logic [`XLEN-1:0] InstrMisalignedAdrM, IEUAdrM,
input logic [31:0] InstrM,
input logic InstrValidM, CommittedM,
input logic InstrValidM, LSUStall,
output logic TrapM, MTrapM, STrapM, UTrapM, RetM,
output logic InterruptM,
output logic ExceptionM,
@ -61,12 +61,12 @@ module trap (
// Determine pending enabled interrupts
// interrupt if any sources are pending
// & with a M stage valid bit to avoid interrupts from interrupt a nonexistent flushed instruction (in the M stage)
// & with ~CommittedM to make sure MEPC isn't chosen so as to rerun the same instr twice
// & with ~LSUStall to make sure MEPC isn't chosen so as to rerun the same instr twice
assign MIntGlobalEnM = (PrivilegeModeW != `M_MODE) || STATUS_MIE; // if M ints enabled or lower priv 3.1.9
assign SIntGlobalEnM = (PrivilegeModeW == `U_MODE) || ((PrivilegeModeW == `S_MODE) && STATUS_SIE); // if in lower priv mode, or if S ints enabled and not in higher priv mode 3.1.9
assign PendingIntsM = ((MIP_REGW & MIE_REGW) & ({12{MIntGlobalEnM}} & 12'h888)) | ((SIP_REGW & SIE_REGW) & ({12{SIntGlobalEnM}} & 12'h222));
assign PendingInterruptM = (|PendingIntsM) & InstrValidM;
assign InterruptM = PendingInterruptM & ~CommittedM;
assign InterruptM = PendingInterruptM & ~LSUStall; // previously CommittedM. The purpose is to delay an interrupt if the instruction in the memory stage is busy in the LSU. LSUStall directly provides this.
//assign ExceptionM = TrapM;
assign ExceptionM = Exception1M;
// *** as of 7/17/21, the system passes with this definition of ExceptionM as being all traps and fails if ExceptionM = Exception1M

5
wally-pipelined/src/wally/wallypipelinedhart.sv
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@ -125,7 +125,6 @@ module wallypipelinedhart (
(* mark_debug = "true" *) logic [`XLEN-1:0] IEUAdrM;
(* mark_debug = "true" *) logic [`XLEN-1:0] ReadDataM;
logic [`XLEN-1:0] ReadDataW;
logic CommittedM;
// AHB ifu interface
logic [`PA_BITS-1:0] InstrPAdrF;
@ -240,7 +239,7 @@ module wallypipelinedhart (
// CPU interface
.MemRWM, .Funct3M, .Funct7M(InstrM[31:25]),
.AtomicM, .ExceptionM, .PendingInterruptM,
.CommittedM, .DCacheMiss, .DCacheAccess,
.DCacheMiss, .DCacheAccess,
.SquashSCW,
//.DataMisalignedM(DataMisalignedM),
.IEUAdrE, .IEUAdrM, .WriteDataM,
@ -314,7 +313,7 @@ module wallypipelinedhart (
.InstrM, .CSRReadValW, .PrivilegedNextPCM,
.RetM, .TrapM,
.ITLBFlushF, .DTLBFlushM,
.InstrValidM, .CommittedM,
.InstrValidM, .LSUStall,
.FRegWriteM, .LoadStallD,
.BPPredDirWrongM, .BTBPredPCWrongM,
.RASPredPCWrongM, .BPPredClassNonCFIWrongM,