diff --git a/wally-pipelined/config/busybear/wally-config.vh b/wally-pipelined/config/busybear/wally-config.vh
index dc4d64515..f61df4283 100644
--- a/wally-pipelined/config/busybear/wally-config.vh
+++ b/wally-pipelined/config/busybear/wally-config.vh
@@ -89,3 +89,4 @@
`define TWO_BIT_PRELOAD "../config/busybear/twoBitPredictor.txt"
`define BTB_PRELOAD "../config/busybear/BTBPredictor.txt"
+`define BPTYPE "BPGLOBAL" // BPGLOBAL or BPTWOBIT
diff --git a/wally-pipelined/config/coremark/wally-config.vh b/wally-pipelined/config/coremark/wally-config.vh
index 69a490fb3..0418a1b8d 100644
--- a/wally-pipelined/config/coremark/wally-config.vh
+++ b/wally-pipelined/config/coremark/wally-config.vh
@@ -92,3 +92,4 @@
`define TWO_BIT_PRELOAD "../config/coremark/twoBitPredictor.txt"
`define BTB_PRELOAD "../config/coremark/BTBPredictor.txt"
+`define BPTYPE "BPGLOBAL" // BPGLOBAL or BPTWOBIT
diff --git a/wally-pipelined/config/rv32ic/wally-config.vh b/wally-pipelined/config/rv32ic/wally-config.vh
index e68f84161..0f9e1eafa 100644
--- a/wally-pipelined/config/rv32ic/wally-config.vh
+++ b/wally-pipelined/config/rv32ic/wally-config.vh
@@ -88,3 +88,4 @@
`define TWO_BIT_PRELOAD "../config/rv32ic/twoBitPredictor.txt"
`define BTB_PRELOAD "../config/rv32ic/BTBPredictor.txt"
+`define BPTYPE "BPGLOBAL" // BPGLOBAL or BPTWOBIT
diff --git a/wally-pipelined/config/rv64ic/wally-config.vh b/wally-pipelined/config/rv64ic/wally-config.vh
index 6fa712720..390417d63 100644
--- a/wally-pipelined/config/rv64ic/wally-config.vh
+++ b/wally-pipelined/config/rv64ic/wally-config.vh
@@ -91,3 +91,4 @@
`define TWO_BIT_PRELOAD "../config/rv64ic/twoBitPredictor.txt"
`define BTB_PRELOAD "../config/rv64ic/BTBPredictor.txt"
+`define BPTYPE "BPGLOBAL" // BPGLOBAL or BPTWOBIT
diff --git a/wally-pipelined/config/rv64icfd/wally-config.vh b/wally-pipelined/config/rv64icfd/wally-config.vh
index be8d7c8a7..c907df536 100644
--- a/wally-pipelined/config/rv64icfd/wally-config.vh
+++ b/wally-pipelined/config/rv64icfd/wally-config.vh
@@ -91,3 +91,4 @@
`define TWO_BIT_PRELOAD "../config/rv64icfd/twoBitPredictor.txt"
`define BTB_PRELOAD "../config/rv64icfd/BTBPredictor.txt"
+`define BPTYPE "BPGLOBAL" // BPGLOBAL or BPTWOBIT
diff --git a/wally-pipelined/src/ifu/bpred.sv b/wally-pipelined/src/ifu/bpred.sv
index 35ac6cfb5..ad0f25d5a 100644
--- a/wally-pipelined/src/ifu/bpred.sv
+++ b/wally-pipelined/src/ifu/bpred.sv
@@ -66,14 +66,32 @@ module bpred
// Part 1 branch direction prediction
- twoBitPredictor DirPredictor(.clk(clk),
- .reset(reset),
- .LookUpPC(PCNextF),
- .Prediction(BPPredF),
- // update
- .UpdatePC(PCE),
- .UpdateEN(InstrClassE[0]),
- .UpdatePrediction(UpdateBPPredE));
+generate
+ if (`BPTYPE == "BPTWOBIT") begin:Predictor
+ twoBitPredictor DirPredictor(.clk(clk),
+ .reset(reset),
+ .LookUpPC(PCNextF),
+ .Prediction(BPPredF),
+ // update
+ .UpdatePC(PCE),
+ .UpdateEN(InstrClassE[0]),
+ .UpdatePrediction(UpdateBPPredE));
+
+ end else if (`BPTYPE == "BPGLOBAL") begin:Predictor
+
+ globalHistoryPredictor DirPredictor(.clk(clk),
+ .reset(reset),
+ .*, // Stalls and flushes
+ .LookUpPC(PCNextF),
+ .Prediction(BPPredF),
+ // update
+ .UpdatePC(PCE),
+ .UpdateEN(InstrClassE[0]),
+ .PCSrcE(PCSrcE),
+ .UpdatePrediction(UpdateBPPredE));
+ end
+endgenerate
+
// this predictor will have two pieces of data,
// 1) A direction (1 = Taken, 0 = Not Taken)
diff --git a/wally-pipelined/src/ifu/globalHistoryPredictor.sv b/wally-pipelined/src/ifu/globalHistoryPredictor.sv
new file mode 100644
index 000000000..58e3f514d
--- /dev/null
+++ b/wally-pipelined/src/ifu/globalHistoryPredictor.sv
@@ -0,0 +1,110 @@
+///////////////////////////////////////////
+// globalHistoryPredictor.sv
+//
+// Written: Shreya Sanghai
+// Email: ssanghai@hmc.edu
+// Created: March 16, 2021
+// Modified:
+//
+// Purpose: Global History Branch predictor with parameterized global history register
+//
+// A component of the Wally configurable RISC-V project.
+//
+// Copyright (C) 2021 Harvey Mudd College & Oklahoma State University
+//
+// 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 globalHistoryPredictor
+ #(parameter int k = 10
+ )
+ (input logic clk,
+ input logic reset,
+ input logic StallF, StallD, StallE, FlushF, FlushD, FlushE,
+ input logic [`XLEN-1:0] LookUpPC,
+ output logic [1:0] Prediction,
+ // update
+ input logic [`XLEN-1:0] UpdatePC,
+ input logic UpdateEN, PCSrcE, /// *** need to add as input from bpred.sv
+ input logic [1:0] UpdatePrediction
+
+ );
+ localparam int Depth = 2^k;
+ logic [k-1:0] GHRF, GHRD, GHRE;
+
+ flopenr #(k) GlobalHistoryRegister(.clk(clk),
+ .reset(reset),
+ .en(UpdateEN),
+ .d({PCSrcE, GHRF[k-1:1] }),
+ .q(GHRF));
+
+
+
+ logic [1:0] PredictionMemory;
+ logic DoForwarding, DoForwardingF;
+ logic [1:0] UpdatePredictionF;
+
+ // for gshare xor the PC with the GHR
+ // TODO: change in sram memory2 module
+ // assign UpdatePCIndex = GHRE ^ UpdatePC;
+ // assign LookUpPCIndex = LookUpPC ^ GHR;
+ // Make Prediction by reading the correct address in the PHT and also update the new address in the PHT
+ // GHR referes to the address that the past k branches points to in the prediction stage
+ // GHRE refers to the address that the past k branches points to in the exectution stage
+ SRAM2P1R1W #(Depth, 2) PHT(.clk(clk),
+ .reset(reset),
+ .RA1(GHRF),
+ .RD1(PredictionMemory),
+ .REN1(1'b1),
+ .WA1(GHRE),
+ .WD1(UpdatePrediction),
+ .WEN1(UpdateEN),
+ .BitWEN1(2'b11));
+
+
+ // need to forward when updating to the same address as reading.
+ // first we compare to see if the update and lookup addreses are the same
+ assign DoForwarding = GHRF == GHRE;
+
+ // register the update value and the forwarding signal into the Fetch stage
+ // TODO: add stall logic ***
+ flopr #(1) DoForwardingReg(.clk(clk),
+ .reset(reset),
+ .d(DoForwarding),
+ .q(DoForwardingF));
+
+ flopr #(2) UpdatePredictionReg(.clk(clk),
+ .reset(reset),
+ .d(UpdatePrediction),
+ .q(UpdatePredictionF));
+
+ assign Prediction = DoForwardingF ? UpdatePredictionF : PredictionMemory;
+
+ //pipeline for GHR
+ flopenrc #(k) GHRDReg(.clk(clk),
+ .reset(reset),
+ .en(~StallD),
+ .clear(FlushD),
+ .d(GHRF),
+ .q(GHRD));
+
+ flopenrc #(k) GHREReg(.clk(clk),
+ .reset(reset),
+ .en(~StallE),
+ .clear(FlushE),
+ .d(GHRD),
+ .q(GHRE));
+
+endmodule
diff --git a/wally-pipelined/testbench/testbench-imperas.sv b/wally-pipelined/testbench/testbench-imperas.sv
index 3c9c4cc91..916420a93 100644
--- a/wally-pipelined/testbench/testbench-imperas.sv
+++ b/wally-pipelined/testbench/testbench-imperas.sv
@@ -474,7 +474,7 @@ string tests32i[] = {
// initialize the branch predictor
initial begin
- $readmemb(`TWO_BIT_PRELOAD, dut.hart.ifu.bpred.DirPredictor.memory.memory);
+ $readmemb(`TWO_BIT_PRELOAD, dut.hart.ifu.bpred.Predictor.DirPredictor.PHT.memory);
$readmemb(`BTB_PRELOAD, dut.hart.ifu.bpred.TargetPredictor.memory.memory);
end