51. Opcode Decoder

Map a 2-bit opcode to a 4-bit one-hot alu_op. This is a parallel decode task (exactly one output bit high).

Requirements

• Module: alu_decoder
• Inputs: opcode[1:0]
• Outputs: alu_op[3:0]

Behaviour

• opcode = 2'b00 → alu_op = 4'b0001
• opcode = 2'b01 → alu_op = 4'b0010
• opcode = 2'b10 → alu_op = 4'b0100
• opcode = 2'b11 → alu_op = 4'b1000
• default → alu_op = 4'b0000