From 0081ff92f9a10500805e2bc29c8afbacc5ee98c7 Mon Sep 17 00:00:00 2001 From: Ross Thompson Date: Fri, 6 Jan 2023 00:09:18 -0600 Subject: [PATCH] Addd missing file. --- pipelined/src/ifu/oldgsharepredictor2.sv | 134 +++++++++++++++++++++++ 1 file changed, 134 insertions(+) create mode 100644 pipelined/src/ifu/oldgsharepredictor2.sv diff --git a/pipelined/src/ifu/oldgsharepredictor2.sv b/pipelined/src/ifu/oldgsharepredictor2.sv new file mode 100644 index 000000000..2fe200a62 --- /dev/null +++ b/pipelined/src/ifu/oldgsharepredictor2.sv @@ -0,0 +1,134 @@ +/////////////////////////////////////////// +// globalHistoryPredictor.sv +// +// Written: Shreya Sanghai +// Email: ssanghai@hmc.edu +// Created: March 16, 2021 +// Modified: +// +// Purpose: Gshare predictor with parameterized global history register +// +// A component of the Wally configurable RISC-V project. +// +// Copyright (C) 2021 Harvey Mudd College & Oklahoma State University +// +// MIT LICENSE +// Permission is hereby granted, free of charge, to any person obtaining a copy of this +// software and associated documentation files (the "Software"), to deal in the Software +// without restriction, including without limitation the rights to use, copy, modify, merge, +// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons +// to whom the Software is furnished to do so, subject to the following conditions: +// +// The above copyright notice and this permission notice shall be included in all copies or +// substantial portions of the Software. +// +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, +// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR +// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS +// BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, +// TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE +// OR OTHER DEALINGS IN THE SOFTWARE. +//////////////////////////////////////////////////////////////////////////////////////////////// + +`include "wally-config.vh" +module oldgsharepredictor2 + (input logic clk, + input logic reset, + input logic StallF, StallD, StallE, StallM, StallW, + input logic FlushD, FlushE, FlushM, FlushW, + input logic [`XLEN-1:0] PCNextF, PCF, PCD, PCE, PCM, + output logic [1:0] DirPredictionF, + // update + input logic [4:0] InstrClassE, + input logic [4:0] BPInstrClassE, + input logic [4:0] BPInstrClassD, + input logic [4:0] BPInstrClassF, + output logic DirPredictionWrongE, + + input logic PCSrcE + + ); + logic [`BPRED_SIZE+1:0] GHR, GHRNext; + logic [`BPRED_SIZE-1:0] PHTUpdateAdr, PHTUpdateAdr0, PHTUpdateAdr1; + logic PHTUpdateEN; + logic BPClassWrongNonCFI; + logic BPClassWrongCFI; + logic BPClassRightNonCFI; + logic BPClassRightBPWrong; + logic BPClassRightBPRight; + logic [1:0] DirPredictionD, DirPredictionE; + logic [1:0] NewDirPredictionE; + + logic [6:0] GHRMuxSel; + logic GHRUpdateEN; + logic [`BPRED_SIZE-1:0] GHRLookup; + + assign BPClassRightNonCFI = ~BPInstrClassE[0] & ~InstrClassE[0]; + assign BPClassWrongCFI = ~BPInstrClassE[0] & InstrClassE[0]; + assign BPClassWrongNonCFI = BPInstrClassE[0] & ~InstrClassE[0]; + assign BPClassRightBPWrong = BPInstrClassE[0] & InstrClassE[0] & DirPredictionWrongE; + assign BPClassRightBPRight = BPInstrClassE[0] & InstrClassE[0] & ~DirPredictionWrongE; + + + // GHR update selection, 1 hot encoded. + assign GHRMuxSel[0] = ~BPInstrClassF[0] & (BPClassRightNonCFI | BPClassRightBPRight); + assign GHRMuxSel[1] = BPClassWrongCFI & ~BPInstrClassD[0]; + assign GHRMuxSel[2] = BPClassWrongNonCFI & ~BPInstrClassD[0]; + assign GHRMuxSel[3] = (BPClassRightBPWrong & ~BPInstrClassD[0]) | (BPClassWrongCFI & BPInstrClassD[0]); + assign GHRMuxSel[4] = BPClassWrongNonCFI & BPInstrClassD[0]; + assign GHRMuxSel[5] = InstrClassE[0] & BPClassRightBPWrong & BPInstrClassD[0]; + assign GHRMuxSel[6] = BPInstrClassF[0] & (BPClassRightNonCFI | (InstrClassE[0] & BPClassRightBPRight)); + assign GHRUpdateEN = (| GHRMuxSel[5:1] & ~StallE) | GHRMuxSel[6] & ~StallF; + + // hoping this created a AND-OR mux. + always_comb begin + case (GHRMuxSel) + 7'b000_0001: GHRNext = GHR[`BPRED_SIZE-1+2:0]; // no change + 7'b000_0010: GHRNext = {GHR[`BPRED_SIZE-2+2:0], PCSrcE}; // branch update + 7'b000_0100: GHRNext = {1'b0, GHR[`BPRED_SIZE+1:1]}; // repair 1 + 7'b000_1000: GHRNext = {GHR[`BPRED_SIZE-1+2:1], PCSrcE}; // branch update with mis prediction correction + 7'b001_0000: GHRNext = {2'b00, GHR[`BPRED_SIZE+1:2]}; // repair 2 + 7'b010_0000: GHRNext = {1'b0, GHR[`BPRED_SIZE+1:2], PCSrcE}; // branch update + repair 1 + 7'b100_0000: GHRNext = {GHR[`BPRED_SIZE-2+2:0], DirPredictionF[1]}; // speculative update + default: GHRNext = GHR[`BPRED_SIZE-1+2:0]; + endcase + end + + flopenr #(`BPRED_SIZE+2) GlobalHistoryRegister(.clk(clk), + .reset(reset), + .en((GHRUpdateEN)), + .d(GHRNext), + .q(GHR)); + + // if actively updating the GHR at the time of prediction we want to us + // GHRNext as the lookup rather than GHR. + + assign PHTUpdateAdr0 = InstrClassE[0] ? GHR[`BPRED_SIZE:1] : GHR[`BPRED_SIZE-1:0]; + assign PHTUpdateAdr1 = InstrClassE[0] ? GHR[`BPRED_SIZE+1:2] : GHR[`BPRED_SIZE:1]; + assign PHTUpdateAdr = BPInstrClassD[0] ? PHTUpdateAdr1 : PHTUpdateAdr0; + assign PHTUpdateEN = InstrClassE[0] & ~StallE; + + assign GHRLookup = |GHRMuxSel[6:1] ? GHRNext[`BPRED_SIZE-1:0] : GHR[`BPRED_SIZE-1:0]; + + // Make Prediction by reading the correct address in the PHT and also update the new address in the PHT + ram2p1r1wb #(`BPRED_SIZE, 2) PHT(.clk(clk), + .reset(reset), + //.RA1(GHR[`BPRED_SIZE-1:0]), + .ra1(GHRLookup ^ PCNextF[`BPRED_SIZE:1]), + .rd1(DirPredictionF), + .ren1(~StallF), + .wa2(PHTUpdateAdr ^ PCE[`BPRED_SIZE:1]), + .wd2(NewDirPredictionE), + .wen2(PHTUpdateEN), + .bwe2(2'b11)); + + // DirPrediction pipeline + flopenr #(2) PredictionRegD(clk, reset, ~StallD, DirPredictionF, DirPredictionD); + flopenr #(2) PredictionRegE(clk, reset, ~StallE, DirPredictionD, DirPredictionE); + + // New prediction pipeline + satCounter2 BPDirUpdateE(.BrDir(PCSrcE), .OldState(DirPredictionE), .NewState(NewDirPredictionE)); + + assign DirPredictionWrongE = PCSrcE != DirPredictionE[1] & InstrClassE[0]; + +endmodule // gsharePredictor