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Temporary commit which gets the no branch predictor implementation working.

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This commit is contained in:
Ross Thompson 2022-02-08 14:13:55 -06:00
parent 853a7bba18
commit aa12d90272
1 changed files with 16 additions and 11 deletions
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27
pipelined/src/ifu/ifu.sv
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@ -243,19 +243,29 @@ module ifu (
assign PrivilegedChangePCM = RetM | TrapM; assign PrivilegedChangePCM = RetM | TrapM;
logic SelBPPredF;
logic [`XLEN-1:0] BPPredPCF, PCNext0F;
logic BPPredWrongM;
// The true correct target is IEUAdrE if PCSrcE is 1 else it is the fall through PCLinkE. // The true correct target is IEUAdrE if PCSrcE is 1 else it is the fall through PCLinkE.
mux2 #(`XLEN) pccorrectemux(.d0(PCLinkE), .d1(IEUAdrE), .s(PCSrcE), .y(PCCorrectE)); mux2 #(`XLEN) pccorrectemux(.d0(PCLinkE), .d1(IEUAdrE), .s(PCSrcE), .y(PCCorrectE));
mux2 #(`XLEN) pcmux2(.d0(PCNext1F), .d1(PCBPWrongInvalidate), .s(InvalidateICacheM), .y(PCNext2F)); mux2 #(`XLEN) pcmux2(.d0(PCNext1F), .d1(PCBPWrongInvalidate), .s(InvalidateICacheM), .y(PCNext2F));
mux2 #(`XLEN) pcmux3(.d0(PCNext2F), .d1(PrivilegedNextPCM), .s(PrivilegedChangePCM), .y(UnalignedPCNextF)); mux2 #(`XLEN) pcmux3(.d0(PCNext2F), .d1(PrivilegedNextPCM), .s(PrivilegedChangePCM), .y(UnalignedPCNextF));
mux2 #(`XLEN) pcmux0(.d0(PCPlus2or4F), .d1(BPPredPCF), .s(SelBPPredF), .y(PCNext0F));
mux2 #(`XLEN) pcmux1(.d0(PCNext0F), .d1(PCCorrectE), .s(BPPredWrongE), .y(PCNext1F));
// Mux only required on instruction class miss prediction.
mux2 #(`XLEN) pcmuxBPWrongInvalidateFlush(.d0(PCE), .d1(PCF),
.s(BPPredWrongM), .y(PCBPWrongInvalidate));
assign PCNextF = {UnalignedPCNextF[`XLEN-1:1], 1'b0}; // hart-SPEC p. 21 about 16-bit alignment assign PCNextF = {UnalignedPCNextF[`XLEN-1:1], 1'b0}; // hart-SPEC p. 21 about 16-bit alignment
flopenl #(`XLEN) pcreg(clk, reset, ~StallF, PCNextF, `RESET_VECTOR, PCF); flopenl #(`XLEN) pcreg(clk, reset, ~StallF, PCNextF, `RESET_VECTOR, PCF);
// branch and jump predictor // branch and jump predictor
if (`BPRED_ENABLED) begin : bpred if (`BPRED_ENABLED) begin : bpred
logic SelBPPredF;
logic [`XLEN-1:0] BPPredPCF, PCNext0F;
logic BPPredWrongM;
bpred bpred(.clk, .reset, bpred bpred(.clk, .reset,
.StallF, .StallD, .StallE, .StallM, .StallF, .StallD, .StallE, .StallM,
@ -264,17 +274,12 @@ module ifu (
.PCD, .PCLinkE, .InstrClassM, .BPPredWrongE, .BPPredWrongM, .PCD, .PCLinkE, .InstrClassM, .BPPredWrongE, .BPPredWrongM,
.BPPredDirWrongM, .BTBPredPCWrongM, .RASPredPCWrongM, .BPPredClassNonCFIWrongM); .BPPredDirWrongM, .BTBPredPCWrongM, .RASPredPCWrongM, .BPPredClassNonCFIWrongM);
mux2 #(`XLEN) pcmux0(.d0(PCPlus2or4F), .d1(BPPredPCF), .s(SelBPPredF), .y(PCNext0F));
mux2 #(`XLEN) pcmux1(.d0(PCNext0F), .d1(PCCorrectE), .s(BPPredWrongE), .y(PCNext1F));
// Mux only required on instruction class miss prediction.
mux2 #(`XLEN) pcmuxBPWrongInvalidateFlush(.d0(PCE), .d1(PCF),
.s(BPPredWrongM), .y(PCBPWrongInvalidate));
end else begin : bpred end else begin : bpred
assign BPPredWrongE = PCSrcE; assign BPPredWrongE = PCSrcE;
assign {BPPredDirWrongM, BTBPredPCWrongM, RASPredPCWrongM, BPPredClassNonCFIWrongM} = '0; assign {BPPredDirWrongM, BTBPredPCWrongM, RASPredPCWrongM, BPPredClassNonCFIWrongM} = '0;
assign PCNext1F = PCPlus2or4F; assign SelBPPredF = 1'b0;
assign PCBPWrongInvalidate = PCE; //assign PCNext1F = PCPlus2or4F;
//assign PCBPWrongInvalidate = PCE;
end end
// pcadder // pcadder