mirror of
https://github.com/openhwgroup/cvw
synced 2025-02-11 06:05:49 +00:00
Addd missing file.
This commit is contained in:
Ross Thompson
parent
cd17d296d2
commit
0081ff92f9
134
pipelined/src/ifu/oldgsharepredictor2.sv
Normal file
134
pipelined/src/ifu/oldgsharepredictor2.sv
Normal file
@ -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
|
||||
Loading…
Reference in New Issue
Block a user