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Eliminated extra register and fixed ports to icache.

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Still need to support physical tag check and write in icache memory.
Still need to reduce to 1 port SRAM in icache.
I would like to refactor the icache code.
This commit is contained in:
Ross Thompson 2021-05-03 12:03:17 -05:00
parent c7b97d0339
commit a54c231489
5 changed files with 175 additions and 302 deletions
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59
wally-pipelined/regression/wave.do
View File

@ -3,6 +3,7 @@ quietly virtual function -install /testbench/dut/hart/ifu/icache/cachemem -env /
quietly WaveActivateNextPane {} 0
add wave -noupdate /testbench/clk
add wave -noupdate /testbench/reset
add wave -noupdate /testbench/memfilename
add wave -noupdate -expand -group {Execution Stage} /testbench/FunctionName/FunctionName/FunctionName
add wave -noupdate -expand -group {Execution Stage} /testbench/dut/hart/ifu/PCE
add wave -noupdate -expand -group {Execution Stage} /testbench/InstrEName
@ -20,13 +21,13 @@ add wave -noupdate -expand -group HDU -group traps /testbench/dut/hart/priv/trap
add wave -noupdate -expand -group HDU -group traps /testbench/dut/hart/priv/trap/LoadPageFaultM
add wave -noupdate -expand -group HDU -group traps /testbench/dut/hart/priv/trap/StorePageFaultM
add wave -noupdate -expand -group HDU -group traps /testbench/dut/hart/priv/trap/InterruptM
add wave -noupdate -expand -group HDU -expand -group hazards /testbench/dut/hart/hzu/BPPredWrongE
add wave -noupdate -expand -group HDU -expand -group hazards /testbench/dut/hart/hzu/CSRWritePendingDEM
add wave -noupdate -expand -group HDU -expand -group hazards /testbench/dut/hart/hzu/RetM
add wave -noupdate -expand -group HDU -expand -group hazards /testbench/dut/hart/hzu/TrapM
add wave -noupdate -expand -group HDU -expand -group hazards /testbench/dut/hart/hzu/LoadStallD
add wave -noupdate -expand -group HDU -expand -group hazards /testbench/dut/hart/hzu/DataStall
add wave -noupdate -expand -group HDU -expand -group hazards /testbench/dut/hart/MulDivStallD
add wave -noupdate -expand -group HDU -group hazards /testbench/dut/hart/hzu/BPPredWrongE
add wave -noupdate -expand -group HDU -group hazards /testbench/dut/hart/hzu/CSRWritePendingDEM
add wave -noupdate -expand -group HDU -group hazards /testbench/dut/hart/hzu/RetM
add wave -noupdate -expand -group HDU -group hazards /testbench/dut/hart/hzu/TrapM
add wave -noupdate -expand -group HDU -group hazards /testbench/dut/hart/hzu/LoadStallD
add wave -noupdate -expand -group HDU -group hazards /testbench/dut/hart/hzu/DataStall
add wave -noupdate -expand -group HDU -group hazards /testbench/dut/hart/MulDivStallD
add wave -noupdate -expand -group HDU -expand -group Flush -color Yellow /testbench/dut/hart/hzu/FlushF
add wave -noupdate -expand -group HDU -expand -group Flush -color Yellow /testbench/dut/hart/FlushD
add wave -noupdate -expand -group HDU -expand -group Flush -color Yellow /testbench/dut/hart/FlushE
@ -37,25 +38,25 @@ add wave -noupdate -expand -group HDU -expand -group Stall -color Orange /testbe
add wave -noupdate -expand -group HDU -expand -group Stall -color Orange /testbench/dut/hart/StallE
add wave -noupdate -expand -group HDU -expand -group Stall -color Orange /testbench/dut/hart/StallM
add wave -noupdate -expand -group HDU -expand -group Stall -color Orange /testbench/dut/hart/StallW
add wave -noupdate -expand -group Bpred -expand -group prediction /testbench/dut/hart/ifu/bpred/bpred/BPPredF
add wave -noupdate -expand -group Bpred -expand -group prediction /testbench/dut/hart/ifu/bpred/bpred/BTBValidF
add wave -noupdate -expand -group Bpred -expand -group prediction /testbench/dut/hart/ifu/bpred/bpred/BPInstrClassF
add wave -noupdate -expand -group Bpred -expand -group prediction /testbench/dut/hart/ifu/bpred/bpred/BTBPredPCF
add wave -noupdate -expand -group Bpred -expand -group prediction /testbench/dut/hart/ifu/bpred/bpred/RASPCF
add wave -noupdate -expand -group Bpred -expand -group update -expand -group dir /testbench/dut/hart/ifu/bpred/bpred/Predictor/DirPredictor/UpdatePC
add wave -noupdate -expand -group Bpred -expand -group update -expand -group dir /testbench/dut/hart/ifu/bpred/bpred/Predictor/DirPredictor/UpdateEN
add wave -noupdate -expand -group Bpred -expand -group update -expand -group dir /testbench/dut/hart/ifu/bpred/bpred/Predictor/DirPredictor/UpdatePrediction
add wave -noupdate -expand -group Bpred -expand -group update -expand -group BTB /testbench/dut/hart/ifu/bpred/bpred/TargetPredictor/UpdateEN
add wave -noupdate -expand -group Bpred -expand -group update -expand -group BTB /testbench/dut/hart/ifu/bpred/bpred/TargetPredictor/UpdatePC
add wave -noupdate -expand -group Bpred -expand -group update -expand -group BTB /testbench/dut/hart/ifu/bpred/bpred/TargetPredictor/UpdateTarget
add wave -noupdate -expand -group Bpred -expand -group {bp wrong} /testbench/dut/hart/ifu/bpred/bpred/TargetWrongE
add wave -noupdate -expand -group Bpred -expand -group {bp wrong} /testbench/dut/hart/ifu/bpred/bpred/FallThroughWrongE
add wave -noupdate -expand -group Bpred -expand -group {bp wrong} /testbench/dut/hart/ifu/bpred/bpred/PredictionPCWrongE
add wave -noupdate -expand -group Bpred -expand -group {bp wrong} /testbench/dut/hart/ifu/bpred/bpred/InstrClassE
add wave -noupdate -expand -group Bpred -expand -group {bp wrong} /testbench/dut/hart/ifu/bpred/bpred/PredictionInstrClassWrongE
add wave -noupdate -expand -group Bpred -expand -group {bp wrong} /testbench/dut/hart/ifu/bpred/bpred/BPPredClassNonCFIWrongE
add wave -noupdate -expand -group Bpred -expand -group {bp wrong} /testbench/dut/hart/ifu/bpred/bpred/BPPredWrongE
add wave -noupdate -expand -group Bpred /testbench/dut/hart/ifu/bpred/bpred/BPPredWrongE
add wave -noupdate -group Bpred -expand -group prediction /testbench/dut/hart/ifu/bpred/bpred/BPPredF
add wave -noupdate -group Bpred -expand -group prediction /testbench/dut/hart/ifu/bpred/bpred/BTBValidF
add wave -noupdate -group Bpred -expand -group prediction /testbench/dut/hart/ifu/bpred/bpred/BPInstrClassF
add wave -noupdate -group Bpred -expand -group prediction /testbench/dut/hart/ifu/bpred/bpred/BTBPredPCF
add wave -noupdate -group Bpred -expand -group prediction /testbench/dut/hart/ifu/bpred/bpred/RASPCF
add wave -noupdate -group Bpred -expand -group update -expand -group dir /testbench/dut/hart/ifu/bpred/bpred/Predictor/DirPredictor/UpdatePC
add wave -noupdate -group Bpred -expand -group update -expand -group dir /testbench/dut/hart/ifu/bpred/bpred/Predictor/DirPredictor/UpdateEN
add wave -noupdate -group Bpred -expand -group update -expand -group dir /testbench/dut/hart/ifu/bpred/bpred/Predictor/DirPredictor/UpdatePrediction
add wave -noupdate -group Bpred -expand -group update -expand -group BTB /testbench/dut/hart/ifu/bpred/bpred/TargetPredictor/UpdateEN
add wave -noupdate -group Bpred -expand -group update -expand -group BTB /testbench/dut/hart/ifu/bpred/bpred/TargetPredictor/UpdatePC
add wave -noupdate -group Bpred -expand -group update -expand -group BTB /testbench/dut/hart/ifu/bpred/bpred/TargetPredictor/UpdateTarget
add wave -noupdate -group Bpred -expand -group {bp wrong} /testbench/dut/hart/ifu/bpred/bpred/TargetWrongE
add wave -noupdate -group Bpred -expand -group {bp wrong} /testbench/dut/hart/ifu/bpred/bpred/FallThroughWrongE
add wave -noupdate -group Bpred -expand -group {bp wrong} /testbench/dut/hart/ifu/bpred/bpred/PredictionPCWrongE
add wave -noupdate -group Bpred -expand -group {bp wrong} /testbench/dut/hart/ifu/bpred/bpred/InstrClassE
add wave -noupdate -group Bpred -expand -group {bp wrong} /testbench/dut/hart/ifu/bpred/bpred/PredictionInstrClassWrongE
add wave -noupdate -group Bpred -expand -group {bp wrong} /testbench/dut/hart/ifu/bpred/bpred/BPPredClassNonCFIWrongE
add wave -noupdate -group Bpred -expand -group {bp wrong} /testbench/dut/hart/ifu/bpred/bpred/BPPredWrongE
add wave -noupdate -group Bpred /testbench/dut/hart/ifu/bpred/bpred/BPPredWrongE
add wave -noupdate -expand -group {instruction pipeline} /testbench/InstrFName
add wave -noupdate -expand -group {instruction pipeline} /testbench/dut/hart/ifu/InstrD
add wave -noupdate -expand -group {instruction pipeline} /testbench/dut/hart/ifu/InstrE
@ -223,8 +224,8 @@ add wave -noupdate -group AHB /testbench/dut/hart/ebu/HADDRD
add wave -noupdate -group AHB /testbench/dut/hart/ebu/HSIZED
add wave -noupdate -group AHB /testbench/dut/hart/ebu/HWRITED
TreeUpdate [SetDefaultTree]
WaveRestoreCursors {{Cursor 2} {5792261 ns} 0} {{Cursor 4} {1318991 ns} 0}
quietly wave cursor active 2
WaveRestoreCursors {{Cursor 2} {5796691 ns} 0} {{Cursor 4} {1318991 ns} 0}
quietly wave cursor active 1
configure wave -namecolwidth 250
configure wave -valuecolwidth 513
configure wave -justifyvalue left
@ -239,4 +240,4 @@ configure wave -griddelta 40
configure wave -timeline 0
configure wave -timelineunits ns
update
WaveRestoreZoom {1311008 ns} {1321254 ns}
WaveRestoreZoom {5795108 ns} {5798036 ns}

122
wally-pipelined/src/cache/dmapped.sv vendored
View File

@ -125,128 +125,6 @@ module rodirectmappedmem #(parameter NUMLINES=512, parameter LINESIZE = 256, par
assign DataValid = DataValidBit && (DataTag == ReadTag);
endmodule
module rodirectmappedmemre #(parameter NUMLINES=512, parameter LINESIZE = 256, parameter WORDSIZE = `XLEN) (
// Pipeline stuff
input logic clk,
input logic reset,
input logic re,
// If flush is high, invalidate the entire cache
input logic flush,
// Select which address to read (broken for efficiency's sake)
input logic [`XLEN-1:12] ReadUpperPAdr,
input logic [11:0] ReadLowerAdr,
// Write new data to the cache
input logic WriteEnable,
input logic [LINESIZE-1:0] WriteLine,
input logic [`XLEN-1:0] WritePAdr,
// Output the word, as well as if it is valid
output logic [31:0] DataWord, // *** was WORDSIZE-1
output logic DataValid
);
// Various compile-time constants
localparam integer WORDWIDTH = $clog2(WORDSIZE/8);
localparam integer OFFSETWIDTH = $clog2(LINESIZE/WORDSIZE);
localparam integer SETWIDTH = $clog2(NUMLINES);
localparam integer TAGWIDTH = `XLEN - OFFSETWIDTH - SETWIDTH - WORDWIDTH;
localparam integer OFFSETBEGIN = WORDWIDTH;
localparam integer OFFSETEND = OFFSETBEGIN+OFFSETWIDTH-1;
localparam integer SETBEGIN = OFFSETEND+1;
localparam integer SETEND = SETBEGIN + SETWIDTH - 1;
localparam integer TAGBEGIN = SETEND + 1;
localparam integer TAGEND = TAGBEGIN + TAGWIDTH - 1;
// Machinery to read from and write to the correct addresses in memory
logic [`XLEN-1:0] ReadPAdr;
logic [`XLEN-1:0] OldReadPAdr;
logic [OFFSETWIDTH-1:0] ReadOffset, WriteOffset;
logic [SETWIDTH-1:0] ReadSet, WriteSet;
logic [TAGWIDTH-1:0] ReadTag, WriteTag;
logic [LINESIZE-1:0] ReadLine;
logic [LINESIZE/WORDSIZE-1:0][WORDSIZE-1:0] ReadLineTransformed;
// Machinery to check if a given read is valid and is the desired value
logic [TAGWIDTH-1:0] DataTag;
logic [NUMLINES-1:0] ValidOut;
logic DataValidBit;
flopenr #(`XLEN) ReadPAdrFlop(clk, reset, re, ReadPAdr, OldReadPAdr);
// Assign the read and write addresses in cache memory
always_comb begin
ReadOffset = OldReadPAdr[OFFSETEND:OFFSETBEGIN];
ReadPAdr = {ReadUpperPAdr, ReadLowerAdr};
ReadSet = ReadPAdr[SETEND:SETBEGIN];
ReadTag = OldReadPAdr[TAGEND:TAGBEGIN];
WriteOffset = WritePAdr[OFFSETEND:OFFSETBEGIN];
WriteSet = WritePAdr[SETEND:SETBEGIN];
WriteTag = WritePAdr[TAGEND:TAGBEGIN];
end
// Depth is number of bits in one "word" of the memory, width is number of such words
Sram1Read1Write #(.DEPTH(LINESIZE), .WIDTH(NUMLINES)) cachemem (
.*,
.ReadAddr(ReadSet),
.ReadData(ReadLine),
.WriteAddr(WriteSet),
.WriteData(WriteLine)
);
Sram1Read1Write #(.DEPTH(TAGWIDTH), .WIDTH(NUMLINES)) cachetags (
.*,
.ReadAddr(ReadSet),
.ReadData(DataTag),
.WriteAddr(WriteSet),
.WriteData(WriteTag)
);
// Pick the right bits coming out the read line
//assign DataWord = ReadLineTransformed[ReadOffset];
//logic [31:0] tempRD;
always_comb begin
case (OldReadPAdr[4:1])
0: DataWord = ReadLine[31:0];
1: DataWord = ReadLine[47:16];
2: DataWord = ReadLine[63:32];
3: DataWord = ReadLine[79:48];
4: DataWord = ReadLine[95:64];
5: DataWord = ReadLine[111:80];
6: DataWord = ReadLine[127:96];
7: DataWord = ReadLine[143:112];
8: DataWord = ReadLine[159:128];
9: DataWord = ReadLine[175:144];
10: DataWord = ReadLine[191:160];
11: DataWord = ReadLine[207:176];
12: DataWord = ReadLine[223:192];
13: DataWord = ReadLine[239:208];
14: DataWord = ReadLine[255:224];
15: DataWord = {16'b0, ReadLine[255:240]};
endcase
end
genvar i;
generate
for (i=0; i < LINESIZE/WORDSIZE; i++) begin
assign ReadLineTransformed[i] = ReadLine[(i+1)*WORDSIZE-1:i*WORDSIZE];
end
endgenerate
// Correctly handle the valid bits
always_ff @(posedge clk, posedge reset) begin
if (reset || flush) begin
ValidOut <= {NUMLINES{1'b0}};
end else begin
if (WriteEnable) begin
ValidOut[WriteSet] <= 1;
end
end
DataValidBit <= ValidOut[ReadSet];
end
assign DataValid = DataValidBit && (DataTag == ReadTag);
endmodule
// Write-through direct-mapped memory
module wtdirectmappedmem #(parameter NUMLINES=512, parameter LINESIZE = 256, parameter WORDSIZE = `XLEN) (

164
wally-pipelined/src/ifu/icache.sv
View File

@ -27,26 +27,24 @@
module icache(
// Basic pipeline stuff
input logic clk, reset,
input logic StallF, StallD,
input logic FlushD,
// Upper bits of physical address for PC
input logic [`XLEN-1:12] UpperPCNextPF,
// Lower 12 bits of virtual PC address, since it's faster this way
input logic [11:0] LowerPCNextF,
input logic clk, reset,
input logic StallF, StallD,
input logic FlushD,
input logic [`XLEN-1:0] PCNextF,
input logic [`XLEN-1:0] PCPF,
// Data read in from the ebu unit
input logic [`XLEN-1:0] InstrInF,
input logic InstrAckF,
input logic [`XLEN-1:0] InstrInF,
input logic InstrAckF,
// Read requested from the ebu unit
output logic [`XLEN-1:0] InstrPAdrF,
output logic InstrReadF,
output logic [`XLEN-1:0] InstrPAdrF,
output logic InstrReadF,
// High if the instruction currently in the fetch stage is compressed
output logic CompressedF,
output logic CompressedF,
// High if the icache is requesting a stall
output logic ICacheStallF,
output logic ICacheStallF,
// The raw (not decompressed) instruction that was requested
// If this instruction is compressed, upper 16 bits may be the next 16 bits or may be zeros
output logic [31:0] InstrRawD
output logic [31:0] InstrRawD
);
// Configuration parameters
@ -96,10 +94,8 @@ module icachecontroller #(parameter LINESIZE = 256) (
// Input the address to read
// The upper bits of the physical pc
input logic [`XLEN-1:12] UpperPCNextPF,
// The lower bits of the virtual pc
input logic [11:0] LowerPCNextF,
input logic [`XLEN-1:0] PCNextF,
input logic [`XLEN-1:0] PCPF,
// Signals to/from cache memory
// The read coming out of it
input logic [31:0] ICacheMemReadData,
@ -198,7 +194,7 @@ module icachecontroller #(parameter LINESIZE = 256) (
logic [LOGWPL:0] FetchCount, NextFetchCount;
logic [`XLEN-1:0] PCPreFinalF, PCPFinalF, PCSpillF, PCNextPF;
logic [`XLEN-1:0] PCPreFinalF, PCPFinalF, PCSpillF;
logic [`XLEN-1:OFFSETWIDTH] PCPTrunkF;
@ -215,7 +211,7 @@ module icachecontroller #(parameter LINESIZE = 256) (
//logic FlushDLastCycleN;
//logic PCPMisalignedF;
localparam [31:0] NOP = 32'h13;
logic [`XLEN-1:0] PCPF;
//logic [`XLEN-1:0] PCPF;
logic reset_q;
@ -224,18 +220,15 @@ module icachecontroller #(parameter LINESIZE = 256) (
//logic MisalignedStall;
// Cache fault signals
//logic FaultStall;
assign PCNextPF = {UpperPCNextPF, LowerPCNextF};
flopenl #(`XLEN) PCPFFlop(clk, reset, SavePC & ~StallF, PCPFinalF, `RESET_VECTOR, PCPF);
//flopenl #(`XLEN) PCPFFlop(clk, reset, SavePC & ~StallF, PCPFinalF, `RESET_VECTOR, PCPF);
// on spill we want to get the first 2 bytes of the next cache block.
// the spill only occurs if the PCPF mod BlockByteLength == -2. Therefore we can
// simply add 2 to land on the next cache block.
assign PCSpillF = PCPF + 2'b10;
// now we have to select between these three PCs
assign PCPreFinalF = PCMux[0] | StallF ? PCPF : PCNextPF; // *** don't like the stallf
//assign PCPreFinalF = PCMux[0] ? PCPF : PCNextPF; // *** don't like the stallf
assign PCPreFinalF = PCMux[0] | StallF ? PCPF : PCNextF; // *** don't like the stallf
assign PCPFinalF = PCMux[1] ? PCSpillF : PCPreFinalF;
@ -247,127 +240,6 @@ module icachecontroller #(parameter LINESIZE = 256) (
assign CompressedF = FinalInstrRawF[1:0] != 2'b11;
// Handle happy path (data in cache, reads aligned)
/* -----\/----- EXCLUDED -----\/-----
generate
if (`XLEN == 32) begin
assign AlignedInstrRawF = PCPF[1] ? MisalignedInstrRawF : ICacheMemReadData;
//assign PCPMisalignedF = PCPF[1] && ~CompressedF;
end else begin
assign AlignedInstrRawF = PCPF[2]
? (PCPF[1] ? MisalignedInstrRawF : ICacheMemReadData[63:32])
: (PCPF[1] ? ICacheMemReadData[47:16] : ICacheMemReadData[31:0]);
//assign PCPMisalignedF = PCPF[2] && PCPF[1] && ~CompressedF;
end
endgenerate
-----/\----- EXCLUDED -----/\----- */
//flopenr #(32) AlignedInstrRawDFlop(clk, reset, ~StallD, AlignedInstrRawF, AlignedInstrRawD);
//flopr #(1) FlushDLastCycleFlop(clk, reset, ~FlushD & (FlushDLastCycleN | ~StallF), FlushDLastCycleN);
//mux2 #(32) InstrRawDMux(AlignedInstrRawD, NOP, ~FlushDLastCycleN, InstrRawD);
// Stall for faults or misaligned reads
/* -----\/----- EXCLUDED -----\/-----
always_comb begin
assign ICacheStallF = FaultStall | MisalignedStall;
end
-----/\----- EXCLUDED -----/\----- */
// Handle misaligned, noncompressed reads
/* -----\/----- EXCLUDED -----\/-----
logic MisalignedState, NextMisalignedState;
logic [15:0] MisalignedHalfInstrF;
logic [15:0] UpperHalfWord;
-----/\----- EXCLUDED -----/\----- */
/* -----\/----- EXCLUDED -----\/-----
flopenr #(16) MisalignedHalfInstrFlop(clk, reset, ~FaultStall & (PCPMisalignedF & MisalignedState), AlignedInstrRawF[15:0], MisalignedHalfInstrF);
flopenr #(1) MisalignedStateFlop(clk, reset, ~FaultStall, NextMisalignedState, MisalignedState);
-----/\----- EXCLUDED -----/\----- */
// When doing a misaligned read, swizzle the bits correctly
/* -----\/----- EXCLUDED -----\/-----
generate
if (`XLEN == 32) begin
assign UpperHalfWord = ICacheMemReadData[31:16];
end else begin
assign UpperHalfWord = ICacheMemReadData[63:48];
end
endgenerate
always_comb begin
if (MisalignedState) begin
assign MisalignedInstrRawF = {16'b0, UpperHalfWord};
end else begin
assign MisalignedInstrRawF = {ICacheMemReadData[15:0], MisalignedHalfInstrF};
end
end
-----/\----- EXCLUDED -----/\----- */
// Manage internal state and stall when necessary
/* -----\/----- EXCLUDED -----\/-----
always_comb begin
assign MisalignedStall = PCPMisalignedF & MisalignedState;
assign NextMisalignedState = ~PCPMisalignedF | ~MisalignedState;
end
-----/\----- EXCLUDED -----/\----- */
// Pick the correct address to read
/* -----\/----- EXCLUDED -----\/-----
generate
if (`XLEN == 32) begin
assign ICacheMemReadLowerAdr = {LowerPCNextF[11:2] + (PCPMisalignedF & ~MisalignedState), 2'b00};
end else begin
assign ICacheMemReadLowerAdr = {LowerPCNextF[11:3] + (PCPMisalignedF & ~MisalignedState), 3'b00};
end
endgenerate
-----/\----- EXCLUDED -----/\----- */
// TODO Handle reading instructions that cross page boundaries
//assign ICacheMemReadUpperPAdr = UpperPCNextPF;
// Handle cache faults
/* -----\/----- EXCLUDED -----\/-----
logic FetchState, BeginFetchState;
logic [LOGWPL:0] FetchWordNum, NextFetchWordNum;
logic [`XLEN-1:0] LineAlignedPCPF;
flopr #(1) FetchStateFlop(clk, reset, BeginFetchState | (FetchState & ~EndFetchState), FetchState);
flopr #(LOGWPL+1) FetchWordNumFlop(clk, reset, NextFetchWordNum, FetchWordNum);
// Enter the fetch state when we hit a cache fault
always_comb begin
BeginFetchState = ~ICacheMemReadValid & ~FetchState & (FetchWordNum == 0);
end
// Exit the fetch state once the cache line has been loaded
flopr #(1) EndFetchStateFlop(clk, reset, ICacheMemWriteEnable, EndFetchState);
// Machinery to request the correct addresses from main memory
always_comb begin
InstrReadF = FetchState & ~EndFetchState & ~ICacheMemWriteEnable; // next stage logic
LineAlignedPCPF = {ICacheMemReadUpperPAdr, ICacheMemReadLowerAdr[11:OFFSETWIDTH], {OFFSETWIDTH{1'b0}}}; // the fetch address for abh?
InstrPAdrF = LineAlignedPCPF + FetchWordNum*(`XLEN/8); // ?
NextFetchWordNum = FetchState ? FetchWordNum+InstrAckF : {LOGWPL+1{1'b0}}; // convert to enable
end
// Write to cache memory when we have the line here
always_comb begin
ICacheMemWritePAdr = LineAlignedPCPF;
ICacheMemWriteEnable = FetchWordNum == {1'b1, {LOGWPL{1'b0}}} & FetchState & ~EndFetchState;
end
// Stall the pipeline while loading a new line from memory
always_comb begin
FaultStall = FetchState | ~ICacheMemReadValid;
end
-----/\----- EXCLUDED -----/\----- */
// the FSM is always runing, do not stall.
flopr #(5) stateReg(.clk(clk),
.reset(reset),

124
wally-pipelined/src/ifu/icacheMem.sv Normal file
View File

@ -0,0 +1,124 @@
`include "wally-config.vh"
module rodirectmappedmemre #(parameter NUMLINES=512, parameter LINESIZE = 256, parameter WORDSIZE = `XLEN) (
// Pipeline stuff
input logic clk,
input logic reset,
input logic re,
// If flush is high, invalidate the entire cache
input logic flush,
// Select which address to read (broken for efficiency's sake)
input logic [`XLEN-1:12] ReadUpperPAdr, // physical address Must come one cycle later
input logic [11:0] ReadLowerAdr, // virtual address
// Write new data to the cache
input logic WriteEnable,
input logic [LINESIZE-1:0] WriteLine,
input logic [`XLEN-1:0] WritePAdr,
// Output the word, as well as if it is valid
output logic [31:0] DataWord, // *** was WORDSIZE-1
output logic DataValid
);
// Various compile-time constants
localparam integer WORDWIDTH = $clog2(WORDSIZE/8);
localparam integer OFFSETWIDTH = $clog2(LINESIZE/WORDSIZE);
localparam integer SETWIDTH = $clog2(NUMLINES);
localparam integer TAGWIDTH = `XLEN - OFFSETWIDTH - SETWIDTH - WORDWIDTH;
localparam integer OFFSETBEGIN = WORDWIDTH;
localparam integer OFFSETEND = OFFSETBEGIN+OFFSETWIDTH-1;
localparam integer SETBEGIN = OFFSETEND+1;
localparam integer SETEND = SETBEGIN + SETWIDTH - 1;
localparam integer TAGBEGIN = SETEND + 1;
localparam integer TAGEND = TAGBEGIN + TAGWIDTH - 1;
// Machinery to read from and write to the correct addresses in memory
logic [`XLEN-1:0] ReadPAdr;
logic [`XLEN-1:0] OldReadPAdr;
logic [OFFSETWIDTH-1:0] ReadOffset, WriteOffset;
logic [SETWIDTH-1:0] ReadSet, WriteSet;
logic [TAGWIDTH-1:0] ReadTag, WriteTag;
logic [LINESIZE-1:0] ReadLine;
logic [LINESIZE/WORDSIZE-1:0][WORDSIZE-1:0] ReadLineTransformed;
// Machinery to check if a given read is valid and is the desired value
logic [TAGWIDTH-1:0] DataTag;
logic [NUMLINES-1:0] ValidOut;
logic DataValidBit;
flopenr #(`XLEN) ReadPAdrFlop(clk, reset, re, ReadPAdr, OldReadPAdr);
// Assign the read and write addresses in cache memory
always_comb begin
ReadOffset = OldReadPAdr[OFFSETEND:OFFSETBEGIN];
ReadPAdr = {ReadUpperPAdr, ReadLowerAdr};
ReadSet = ReadPAdr[SETEND:SETBEGIN];
ReadTag = OldReadPAdr[TAGEND:TAGBEGIN];
WriteOffset = WritePAdr[OFFSETEND:OFFSETBEGIN];
WriteSet = WritePAdr[SETEND:SETBEGIN];
WriteTag = WritePAdr[TAGEND:TAGBEGIN];
end
// Depth is number of bits in one "word" of the memory, width is number of such words
Sram1Read1Write #(.DEPTH(LINESIZE), .WIDTH(NUMLINES)) cachemem (
.*,
.ReadAddr(ReadSet),
.ReadData(ReadLine),
.WriteAddr(WriteSet),
.WriteData(WriteLine)
);
Sram1Read1Write #(.DEPTH(TAGWIDTH), .WIDTH(NUMLINES)) cachetags (
.*,
.ReadAddr(ReadSet),
.ReadData(DataTag),
.WriteAddr(WriteSet),
.WriteData(WriteTag)
);
// Pick the right bits coming out the read line
//assign DataWord = ReadLineTransformed[ReadOffset];
//logic [31:0] tempRD;
always_comb begin
case (OldReadPAdr[4:1])
0: DataWord = ReadLine[31:0];
1: DataWord = ReadLine[47:16];
2: DataWord = ReadLine[63:32];
3: DataWord = ReadLine[79:48];
4: DataWord = ReadLine[95:64];
5: DataWord = ReadLine[111:80];
6: DataWord = ReadLine[127:96];
7: DataWord = ReadLine[143:112];
8: DataWord = ReadLine[159:128];
9: DataWord = ReadLine[175:144];
10: DataWord = ReadLine[191:160];
11: DataWord = ReadLine[207:176];
12: DataWord = ReadLine[223:192];
13: DataWord = ReadLine[239:208];
14: DataWord = ReadLine[255:224];
15: DataWord = {16'b0, ReadLine[255:240]};
endcase
end
genvar i;
generate
for (i=0; i < LINESIZE/WORDSIZE; i++) begin
assign ReadLineTransformed[i] = ReadLine[(i+1)*WORDSIZE-1:i*WORDSIZE];
end
endgenerate
// Correctly handle the valid bits
always_ff @(posedge clk, posedge reset) begin
if (reset || flush) begin
ValidOut <= {NUMLINES{1'b0}};
end else begin
if (WriteEnable) begin
ValidOut[WriteSet] <= 1;
end
end
DataValidBit <= ValidOut[ReadSet];
end
assign DataValid = DataValidBit && (DataTag == ReadTag);
endmodule

8
wally-pipelined/src/ifu/ifu.sv
View File

@ -105,11 +105,9 @@ module ifu (
// jarred 2021-03-14 Add instrution cache block to remove rd2
assign PCNextPF = PCNextF; // Temporary workaround until iTLB is live
icache icache(
.*,
.UpperPCNextPF(PCNextPF[`XLEN-1:12]),
.LowerPCNextF(PCNextPF[11:0])
);
icache icache(.*);
assign PrivilegedChangePCM = RetM | TrapM;