`default_nettype none
`timescale 1us/1ns

`include "aluOp.vh"

module alu
(
input wire [31:0] alu_in_1,
input wire[31:0] alu_in_2,
input wire[3:0] alu_op_i,
output wire[31:0] alu_output
);


wire [31:0] diff = alu_in_1 - alu_in_2;

assign alu_output =
	alu_op_i == `ADD ? alu_in_1 + alu_in_2 :
	alu_op_i == `SUB ? diff :
	alu_op_i == `XOR ? alu_in_1 ^ alu_in_2 :
	alu_op_i == `OR ? alu_in_1 | alu_in_2 :
	alu_op_i == `AND ? alu_in_1 & alu_in_2 :
	alu_op_i == `SLL ? alu_in_1 << alu_in_2 :
	alu_op_i == `SRL ? alu_in_1 >> alu_in_2 :
	alu_op_i == `SLTU ? (alu_in_1 < alu_in_2 ? 32'b1 : 32'b0) :
	alu_op_i == `NONE ? alu_in_1 :
	alu_op_i == `SLT ? (alu_in_1[31] == alu_in_2[31] ? (diff[31] == 1'b0 ? 32'b0 : 32'b1) : (alu_in_1[31] == 1'b1 ? 32'b1 : 32'b0) ) :
	alu_op_i == `SRA ?  (alu_in_1 >> alu_in_2) | (alu_in_1[31] == 1'b0 ? 32'b0 :
		32'hFFFFFFFF << ((alu_in_2[4] ? 0 : 5'b10000) + (alu_in_2[3] ? 0 : 5'b01000) +
		(alu_in_2[2] ? 0 : 5'b00100) + (alu_in_2[1] ? 0 : 5'b00010) + (alu_in_2[0] ? 0 : 5'b00001))
	) :
	32'b0;

endmodule