`default_nettype none
`timescale 1us/1ns

`include "aluOp.vh"

module alu2
(
input wire [31:0] in1,
input wire[31:0] in2,
input wire[3:0] op,
output wire[31:0] out
);


wire [31:0] diff = in1 - in2;
reg [31:0] result;

always @ (*)
begin
	case (op)
		`ADD: result = in1 + in2;
		`SUB: result = diff;
		`XOR: result = in1 ^ in2;
		`OR: result = in1 | in2;
		`AND: result = in1 & in2;
		`SLL: result = in1 << in2;
		`SRL: result = in1 >> in2;
		`SLTU: result = (in1 < in2 ? 32'b1 : 32'b0);
		`NONE: result = in1;
		`SLT: result = (in1[31] == in2[31] ? (diff[31] == 1'b0 ? 32'b0 : 32'b1) : (in1[31] == 1'b1 ? 32'b1 : 32'b0) );
		`SRA: result = (in1 >> in2) | (in1[31] == 1'b0 ? 32'b0 :
			32'hFFFFFFFF << ((in2[4] ? 0 : 5'b10000) + (in2[3] ? 0 : 5'b01000) +
			(in2[2] ? 0 : 5'b00100) + (in2[1] ? 0 : 5'b00010) + (in2[0] ? 0 : 5'b00001))
		);
		default: result = 32'b0;
	endcase
end

assign out = result;
endmodule