Maybe I finally have the ahead pipelined local history predictor working.

This commit is contained in:
Ross Thompson 2023-05-04 14:11:34 -05:00
parent 060d40853a
commit 8235042ba2
2 changed files with 9 additions and 9 deletions

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@ -135,7 +135,7 @@ module bpred (
end else if (`BPRED_TYPE == "BP_LOCAL_AHEAD") begin:Predictor
localaheadbp #(`BPRED_NUM_LHR, `BPRED_SIZE) DirPredictor(.clk, .reset,
.StallF, .StallD, .StallE, .StallM, .StallW, .FlushD, .FlushE, .FlushM, .FlushW,
.PCNextF, .PCM, .BPDirPredD(BPDirPredF), .BPDirPredWrongE,
.PCNextF, .PCM, .BPDirPredF(BPDirPredF), .BPDirPredWrongE,
.BranchE, .BranchM, .PCSrcE);
end

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@ -35,7 +35,7 @@ module localaheadbp #(parameter m = 6, // 2^m = number of local history branches
input logic reset,
input logic StallF, StallD, StallE, StallM, StallW,
input logic FlushD, FlushE, FlushM, FlushW,
output logic [1:0] BPDirPredD,
output logic [1:0] BPDirPredF,
output logic BPDirPredWrongE,
// update
input logic [`XLEN-1:0] PCNextF, PCM,
@ -43,8 +43,8 @@ module localaheadbp #(parameter m = 6, // 2^m = number of local history branches
);
logic [k-1:0] IndexNextF, IndexM;
//logic [1:0] BPDirPredD, BPDirPredE;
logic [1:0] BPDirPredE;
logic [1:0] BPDirPredD, BPDirPredE;
//logic [1:0] BPDirPredE;
logic [1:0] NewBPDirPredE, NewBPDirPredM;
logic [k-1:0] LHRF, LHRD, LHRE, LHRM, LHRW, LHRNextF;
@ -58,18 +58,18 @@ module localaheadbp #(parameter m = 6, // 2^m = number of local history branches
logic UpdateM;
//assign IndexNextF = LHR;
assign IndexM = LHRM;
assign IndexM = LHRW;
ram2p1r1wbe #(2**k, 2) PHT(.clk(clk),
.ce1(~StallF), .ce2(~StallW & ~FlushW),
.ra1(LHRF),
.rd1(BPDirPredD),
.rd1(BPDirPredF),
.wa2(IndexM),
.wd2(NewBPDirPredM),
.we2(BranchM),
.bwe2(1'b1));
//flopenrc #(2) PredictionRegD(clk, reset, FlushD, ~StallD, BPDirPredF, BPDirPredD);
flopenrc #(2) PredictionRegD(clk, reset, FlushD, ~StallD, BPDirPredF, BPDirPredD);
flopenrc #(2) PredictionRegE(clk, reset, FlushE, ~StallE, BPDirPredD, BPDirPredE);
satCounter2 BPDirUpdateE(.BrDir(PCSrcE), .OldState(BPDirPredE), .NewState(NewBPDirPredE));
@ -83,7 +83,7 @@ module localaheadbp #(parameter m = 6, // 2^m = number of local history branches
// GHR is both read and update in M. GHR is still pipelined so that the PHT is updated with the correct
// GHR. Local history in contrast must pipeline the specific history register read during F and then update
// that same one in M. This implementation does not forward if a branch matches in the D, E, or M stages.
assign LHRNextW = BranchM ? {PCSrcM, LHRM[k-1:1]} : LHRM;
assign LHRNextW = BranchM ? {PCSrcM, LHRW[k-1:1]} : LHRW;
// this is local history
//genvar index;
@ -107,7 +107,7 @@ module localaheadbp #(parameter m = 6, // 2^m = number of local history branches
flopenrc #(k) LHRDReg(clk, reset, FlushD, ~StallD, LHRF, LHRD);
flopenrc #(k) LHREReg(clk, reset, FlushE, ~StallE, LHRD, LHRE);
flopenrc #(k) LHRMReg(clk, reset, FlushM, ~StallM, LHRE, LHRM);
flopenrc #(k) LHRWReg(clk, reset, FlushW, ~StallW, LHRNextW, LHRW);
flopenrc #(k) LHRWReg(clk, reset, FlushW, ~StallW, LHRM, LHRW);
flopenr #(`XLEN) PCWReg(clk, reset, ~StallW, PCM, PCW);