Techniques are disclosed relating to sharing an arithmetic logic unit (ALU) between multiple threads. In some embodiments, the threads also have dedicated ALUs for other types of operations. In some embodiments, arbitration circuitry is configured to receive operations to be performed by the shared arithmetic logic unit from the set of threads and issue the received operations to the shared arithmetic logic unit. In some embodiments, the arbitration circuitry is configured to switch to a different one of the set of threads for each instruction issued to the shared arithmetic logic unit. In some embodiments, the shared ALU is configured to perform 32-bit operations and the dedicated ALUs are configured to perform the same operations using 16-bit precision. In some embodiments, the shared ALU is shared between two threads and is physically located adjacent to other datapath circuitry for the two threads.