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[/] [an-fpga-implementation-of-low-latency-noc-based-mpsoc/] [trunk/] [mpsoc/] [src_processor/] [mor1kx-5.0/] [rtl/] [verilog/] [mor1kx_branch_prediction.v] - Blame information for rev 48

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1 48 alirezamon 
/******************************************************************************
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 This Source Code Form is subject to the terms of the
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 Open Hardware Description License, v. 1.0. If a copy
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 of the OHDL was not distributed with this file, You
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 can obtain one at http://juliusbaxter.net/ohdl/ohdl.txt
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 Description: Branch prediction module
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 Generates a predicted flag output and compares that to the real flag
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 when it comes back in the following pipeline stage.
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 Signals are deliberately not named after the pipeline stage they belong to,
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 in order to keep this module generic.
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 Copyright (C) 2013 Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
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 Copyright (C) 2016 Alexey Baturo <baturo.alexey@gmail.com>
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 ******************************************************************************/
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`include "mor1kx-defines.v"
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module mor1kx_branch_prediction
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  #(
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    parameter [95:0] FEATURE_BRANCH_PREDICTOR = "SIMPLE",
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    parameter OPTION_OPERAND_WIDTH = 32
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    )
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   (
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   input clk,
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   input rst,
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   // Signals belonging to the stage where the branch is predicted.
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   input op_bf_i,               // from decode stage, brn is bf
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   input op_bnf_i,              // from decode stage, brn is bnf
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   input [9:0] immjbr_upper_i,  // from decode stage, imm
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   input [OPTION_OPERAND_WIDTH - 1:0] brn_pc_i, // pc of brn being predicted
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   output predicted_flag_o,     // to decode-execute stage, flag we predict to be
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   // Signals belonging to the stage where the branch is resolved.
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   input prev_op_brcond_i,      // from decode-execute stage, prev brn was cond
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   input prev_predicted_flag_i, // from decode-execute, prev predicted flag
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   input flag_i,                // from execute-ctrl stage, real flag we got
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   input padv_decode_i,         // is decode stage stalled
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   input execute_bf_i,          // prev insn was bf
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   input execute_bnf_i,         // prev insn was bnf
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   // Branch misprediction indicator
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   output       branch_mispredict_o // to decode-execute stage, was brn mispredicted or not
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   );
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   // Compare the real flag with the previously predicted flag and signal a
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   // misprediction in case of a mismatch.
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   assign branch_mispredict_o = prev_op_brcond_i & (flag_i != prev_predicted_flag_i);
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generate
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if (FEATURE_BRANCH_PREDICTOR=="SAT_COUNTER") begin : branch_predictor_saturation_counter
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   mor1kx_branch_predictor_saturation_counter
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      mor1kx_branch_predictor_saturation_counter
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      (
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         // Outputs
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         .predicted_flag_o                 (predicted_flag_o),
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         // Inputs
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         .clk                              (clk),
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         .rst                              (rst),
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         .flag_i                           (flag_i),
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         .execute_op_bf_i                  (execute_bf_i),
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         .execute_op_bnf_i                 (execute_bnf_i),
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         .op_bf_i                          (op_bf_i),
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         .op_bnf_i                         (op_bnf_i),
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         .prev_op_brcond_i                 (prev_op_brcond_i),
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         .padv_decode_i                    (padv_decode_i),
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         .branch_mispredict_i              (branch_mispredict_o));
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end else if (FEATURE_BRANCH_PREDICTOR=="GSHARE") begin : branch_predictor_gshare
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   mor1kx_branch_predictor_gshare
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     #(
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       .OPTION_OPERAND_WIDTH(OPTION_OPERAND_WIDTH)
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       )
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      mor1kx_branch_predictor_gshare
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      (
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         // Outputs
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         .predicted_flag_o                 (predicted_flag_o),
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         // Inputs
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         .clk                              (clk),
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         .rst                              (rst),
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         .flag_i                           (flag_i),
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         .execute_op_bf_i                  (execute_bf_i),
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         .execute_op_bnf_i                 (execute_bnf_i),
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         .op_bf_i                          (op_bf_i),
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         .brn_pc_i                         (brn_pc_i),
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         .op_bnf_i                         (op_bnf_i),
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         .prev_op_brcond_i                 (prev_op_brcond_i),
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         .padv_decode_i                    (padv_decode_i),
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         .branch_mispredict_i              (branch_mispredict_o));
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end else if (FEATURE_BRANCH_PREDICTOR=="SIMPLE") begin : branch_predictor_simple
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   mor1kx_branch_predictor_simple
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      mor1kx_branch_predictor_simple
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      (
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         // Outputs
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         .predicted_flag_o                 (predicted_flag_o),
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         // Inputs
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         .op_bf_i                          (op_bf_i),
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         .op_bnf_i                         (op_bnf_i),
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         .immjbr_upper_i                   (immjbr_upper_i));
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end else begin
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   initial begin
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      $display("Error: FEATURE_PREDICTOR_TYPE, %s, not valid", FEATURE_BRANCH_PREDICTOR);
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      $finish();
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   end
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end
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endgenerate
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endmodule

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