| // Copyright 2021 cpu-dev |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| module alu_controller(opcode, alu_ctrl); |
| input [3:0] opcode; |
| output [3:0] alu_ctrl; |
| |
| assign alu_ctrl = alu_control(opcode); |
| |
| function [3:0] alu_control(input [3:0] opcode); |
| begin |
| case(opcode) |
| 4'b0001: alu_control = 4'b0000; |
| 4'b0010: alu_control = 4'b1000; |
| 4'b0011: alu_control = 4'b0001; |
| 4'b0100: alu_control = 4'b0010; |
| 4'b0101: alu_control = 4'b0011; |
| 4'b0110: alu_control = 4'b0100; |
| 4'b0111: alu_control = 4'b0101; |
| 4'b1000: alu_control = 4'b0110; |
| 4'b1001: alu_control = 4'b0111; |
| endcase |
| end |
| endfunction |
| endmodule |