Make it easy to add new shuffle sequence operations.
Make it easy to add new shuffle sequence operations.

wenru/ibex,hlplab/hlpspr1,addrummond/ibex,hlplab/hlpspr1,wenru/ibex,wenru/ibex,addrummond/ibex,addrummond/ibex,wenru/ibex,hlplab/hlpspr1,addrummond/ibex