sim2181 is an opcode-level simulator of the core functions of the Analog Devices ADSP-2181 digital signal processor. Not all functions are implemented yet, but it is a good start. It can currently perform all sequencer and DAG operations, as well as data memory accessing and BDMA emulation. All registers basically work. However, ALU, MAC, and shifter operations are not yet executed. (Its not useful yet.) Planned features include real breakpointing, trapping of arbitrary operations, improved interface, and eventually interfacing with the EZ-ICE board.