// Solution for Homework 5C
// J. Dean Brock <brock@unca.edu>

module SerialALU
      (input   logic        CLOCK,
       input   logic  [6:0] INSTRUCTION,
       input   logic [15:0] INPUT,
       output  logic  [2:0] STATUS,
       output  logic [15:0] OUTPUT
      ) ;

   logic [2:0] OPCODE ;
   logic [1:0] SOURCE ;
   logic [1:0] TARGET ;

   assign {OPCODE, SOURCE, TARGET} = INSTRUCTION ;

   logic [15:0] register [1:3] ;
   initial
     begin
       register[1] = 16'd320 ;
       register[2] = 16'hbeef ;
       register[3] = 16'hfade ;
     end

   logic [15:0] source_value ;
   logic [15:0] target_value ;
   logic [15:0] result_value ;

   assign source_value = SOURCE == 2'b00 ? INPUT : register[SOURCE] ;
   assign target_value = TARGET == 2'b00 ? INPUT : register[TARGET] ;

   assign OUTPUT = source_value ^ target_value ;

endmodule