cvw/src/ieu/bmu/zbb.sv

///////////////////////////////////////////
// zbb.sv
//
// Written: Kevin Kim <kekim@hmc.edu> and Kip Macsai-Goren <kmacsaigoren@hmc.edu>
// Created: 2 February 2023
// Modified: March 6 2023
//
// Purpose: RISC-V ZBB top level unit
//
// Documentation: RISC-V System on Chip Design Chapter ***
// 
// A component of the CORE-V-WALLY configurable RISC-V project.
// 
// Copyright (C) 2021-23 Harvey Mudd College & Oklahoma State University
//
// SPDX-License-Identifier: Apache-2.0 WITH SHL-2.1
//
// Licensed under the Solderpad Hardware License v 2.1 (the “License”); you may not use this file 
// except in compliance with the License, or, at your option, the Apache License version 2.0. You 
// may obtain a copy of the License at
//
// https://solderpad.org/licenses/SHL-2.1/
//
// Unless required by applicable law or agreed to in writing, any work distributed under the 
// License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, 
// either express or implied. See the License for the specific language governing permissions 
// and limitations under the License.
////////////////////////////////////////////////////////////////////////////////////////////////

`include "wally-config.vh"

module zbb #(parameter WIDTH=32) (
  input  logic [WIDTH-1:0] A, RevA, B,   // Operands
  input  logic [WIDTH-1:0] ALUResult,    // ALU Result
  input  logic             W64,          // Indicates word operation
  input  logic             lt,           // lt flag
  input  logic [2:0]       ZBBSelect,    // Indicates word operation
  output logic [WIDTH-1:0] ZBBResult);   // ZBB result

  
  // count result
  logic [WIDTH-1:0] CntResult;           
  
  // min,max result
  logic [WIDTH-1:0] MaxResult;           
  logic [WIDTH-1:0] MinResult;           

  // byte results
  logic [WIDTH-1:0] ByteResult;

  // sign/zero extend results
  logic [WIDTH-1:0] ExtResult;           // sign/zero extend result


  cnt #(WIDTH) cnt(.A(A), .RevA(RevA), .B(B[4:0]), .W64(W64), .CntResult(CntResult));
  byteUnit #(WIDTH) bu(.A(A), .ByteSelect(B[0]), .ByteResult(ByteResult));
  ext #(WIDTH) ext(.A(A), .ExtSelect({~B[2], {B[2] & B[0]}}), .ExtResult(ExtResult));


  assign MaxResult = (lt) ? B : A;
  assign MinResult = (lt) ? A : B;

  // ZBB Result select mux
  mux5 #(WIDTH) zbbresultmux(CntResult, ExtResult, ByteResult, MinResult, MaxResult, ZBBSelect, ZBBResult);


endmodule