The PDSP1601 is a high performance 16-bit arithmetic logic unit with an independent on-chip 16-bit barrel shifter. The PDSP1601A has two operating modes giving 20MHz or 10MHz register-to-register transfer rates. The PDSP1601 supports Multicycle multiprecision operation. This allows a single device to operate at 20MHz for 16-bit fields, 10MHz for 32-bit fields and 5MHz for 64-bit fields. The PDSP1601 can also be cascaded to produce wider words at the 20MHz rate using the Carry Out and Carry In pins. The Barrel Shifter is also capable of extension, for example the PDSP1601 can used to select a 16-bit field from a 32-bit input in 100ns.