module e203_exu_longpwbck(




  //////////////////////////////////////////////////////////////
  // The LSU Write-Back Interface
  input  lsu_wbck_i_valid, // Handshake valid
  output lsu_wbck_i_ready, // Handshake ready
  input  [`E203_XLEN-1:0] lsu_wbck_i_wdat,
  input  [`E203_ITAG_WIDTH -1:0] lsu_wbck_i_itag,
  input  lsu_wbck_i_err , // The error exception generated
  input  lsu_cmt_i_buserr ,
  input  [`E203_ADDR_SIZE -1:0] lsu_cmt_i_badaddr,
  input  lsu_cmt_i_ld, 
  input  lsu_cmt_i_st, 

  //////////////////////////////////////////////////////////////
  // The Long pipe instruction Wback interface to final wbck module
  output longp_wbck_o_valid, // Handshake valid
  input  longp_wbck_o_ready, // Handshake ready
  output [`E203_FLEN-1:0] longp_wbck_o_wdat,
  output [5-1:0] longp_wbck_o_flags,
  output [`E203_RFIDX_WIDTH -1:0] longp_wbck_o_rdidx,
  output longp_wbck_o_rdfpu,
  //
  // The Long pipe instruction Exception interface to commit stage
  output  longp_excp_o_valid,
  input   longp_excp_o_ready,
  output  longp_excp_o_insterr,
  output  longp_excp_o_ld,
  output  longp_excp_o_st,
  output  longp_excp_o_buserr , // The load/store bus-error exception generated
  output [`E203_ADDR_SIZE-1:0] longp_excp_o_badaddr,
  output [`E203_PC_SIZE -1:0] longp_excp_o_pc,
  //
  //The itag of toppest entry of OITF
  input  oitf_empty,
  input  [`E203_ITAG_WIDTH -1:0] oitf_ret_ptr,
  input  [`E203_RFIDX_WIDTH-1:0] oitf_ret_rdidx,
  input  [`E203_PC_SIZE-1:0] oitf_ret_pc,
  input  oitf_ret_rdwen,   
  input  oitf_ret_rdfpu,   
  output oitf_ret_ena,
  
  input  clk,
  input  rst_n
  );


  // The Long-pipe instruction can write-back only when it's itag 
  //   is same as the itag of toppest entry of OITF
  wire wbck_ready4lsu = (lsu_wbck_i_itag == oitf_ret_ptr) & (~oitf_empty);
  wire wbck_sel_lsu = lsu_wbck_i_valid & wbck_ready4lsu;

  //assign longp_excp_o_ld   = wbck_sel_lsu & lsu_cmt_i_ld;
  //assign longp_excp_o_st   = wbck_sel_lsu & lsu_cmt_i_st;
  //assign longp_excp_o_buserr = wbck_sel_lsu & lsu_cmt_i_buserr;
  //assign longp_excp_o_badaddr = wbck_sel_lsu ? lsu_cmt_i_badaddr : `E203_ADDR_SIZE'b0;

  assign {
         longp_excp_o_insterr
        ,longp_excp_o_ld   
        ,longp_excp_o_st  
        ,longp_excp_o_buserr
        ,longp_excp_o_badaddr } = 
             ({`E203_ADDR_SIZE+4{wbck_sel_lsu}} & 
              {
                1'b0,
                lsu_cmt_i_ld,
                lsu_cmt_i_st,
                lsu_cmt_i_buserr,
                lsu_cmt_i_badaddr
              }) 
              ;

  //////////////////////////////////////////////////////////////
  // The Final arbitrated Write-Back Interface
  wire wbck_i_ready;
  wire wbck_i_valid;
  wire [`E203_FLEN-1:0] wbck_i_wdat;
  wire [5-1:0] wbck_i_flags;
  wire [`E203_RFIDX_WIDTH-1:0] wbck_i_rdidx;
  wire [`E203_PC_SIZE-1:0] wbck_i_pc;
  wire wbck_i_rdwen;
  wire wbck_i_rdfpu;
  wire wbck_i_err ;

  assign lsu_wbck_i_ready = wbck_ready4lsu & wbck_i_ready;

  assign wbck_i_valid = ({1{wbck_sel_lsu}} & lsu_wbck_i_valid) 
                         ;
  `ifdef E203_FLEN_IS_32 //{
  wire [`E203_FLEN-1:0] lsu_wbck_i_wdat_exd = lsu_wbck_i_wdat;
  `else//}{
  wire [`E203_FLEN-1:0] lsu_wbck_i_wdat_exd = {{`E203_FLEN-`E203_XLEN{1'b0}},lsu_wbck_i_wdat};
  `endif//}
  assign wbck_i_wdat  = ({`E203_FLEN{wbck_sel_lsu}} & lsu_wbck_i_wdat_exd ) 
                         ;
  assign wbck_i_flags  = 5'b0
                         ;
  assign wbck_i_err   = wbck_sel_lsu & lsu_wbck_i_err 
                         ;
  assign wbck_i_pc    = oitf_ret_pc;
  assign wbck_i_rdidx = oitf_ret_rdidx;
  assign wbck_i_rdwen = oitf_ret_rdwen;
  assign wbck_i_rdfpu = oitf_ret_rdfpu;

  // If the instruction have no error and it have the rdwen, then it need to 
  //   write back into regfile, otherwise, it does not need to write regfile
  wire need_wbck = wbck_i_rdwen & (~wbck_i_err);

  // If the long pipe instruction have error result, then it need to handshake
  //   with the commit module.
  wire need_excp = wbck_i_err;

  assign wbck_i_ready = 
       (need_wbck ? longp_wbck_o_ready : 1'b1)
     & (need_excp ? longp_excp_o_ready : 1'b1);


  assign longp_wbck_o_valid = need_wbck & wbck_i_valid & (need_excp ? longp_excp_o_ready : 1'b1);
  assign longp_excp_o_valid = need_excp & wbck_i_valid & (need_wbck ? longp_wbck_o_ready : 1'b1);

  assign longp_wbck_o_wdat  = wbck_i_wdat ;
  assign longp_wbck_o_flags = wbck_i_flags ;
  assign longp_wbck_o_rdfpu = wbck_i_rdfpu ;
  assign longp_wbck_o_rdidx = wbck_i_rdidx;

  assign longp_excp_o_pc    = wbck_i_pc;

  assign oitf_ret_ena = wbck_i_valid & wbck_i_ready;

endmodule