///////////////////////////////////////////
// ieu.sv
//
// Written: David_Harris@hmc.edu 9 January 2021
// Modified: 
//
// Purpose: Integer Execution Unit: datapath and controller
// 
// 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 ieu (
  input  logic             clk, reset,
  // Decode Stage interface
  input  logic [31:0]      InstrD,
  input  logic             IllegalIEUInstrFaultD, 
  output logic             IllegalBaseInstrFaultD,
  // Execute Stage interface
  input  logic [`XLEN-1:0] PCE, 
  output logic [`XLEN-1:0] PCTargetE,
  // Memory stage interface
  input  logic             DataMisalignedM,
  input  logic             DataAccessFaultM,
  output logic [1:0]       MemRWM,
  output logic [`XLEN-1:0] MemAdrM, WriteDataM,
  output logic [`XLEN-1:0] SrcAM,
  output logic [2:0]       Funct3M,
  // Writeback stage
  input  logic [`XLEN-1:0] ReadDataW,
  input  logic [`XLEN-1:0] CSRReadValW,
  input  logic [`XLEN-1:0] PCLinkW,
  output logic             InstrValidW,
  // hazards
  input  logic             StallD, FlushD, FlushE, FlushM, FlushW,
  input  logic             RetM, TrapM,
  output logic             LoadStallD,
  output logic             PCSrcE,

  output logic             CSRWriteM, PrivilegedM,
  output logic             CSRWritePendingDEM
);

  logic [2:0]  ImmSrcD;
  logic [2:0]  FlagsE;
  logic [4:0]  ALUControlE;
  logic        ALUSrcAE, ALUSrcBE;
  logic [1:0]  ResultSrcW;
  logic       TargetSrcE;

  // forwarding signals
  logic [4:0]       Rs1D, Rs2D, Rs1E, Rs2E, RdE, RdM, RdW;
  logic [1:0]       ForwardAE, ForwardBE;
  logic             RegWriteM, RegWriteW;
  logic             MemReadE;
           
  controller c(.OpD(InstrD[6:0]), .Funct3D(InstrD[14:12]), .Funct7b5D(InstrD[30]), .*);
  datapath   dp(.*);             
  forward    fw(.*);
endmodule