MicroTiger is developed to be a graphical microcode simulator with a reconfigurable datapath. The datapath editor window, the main application window, allows for datapath creation and simulation. In addition, several other dialog windows are provided to aid in creating the datapath. The microprogram editor window allows for microprogram and aids in simulation. The ISA code is externally edited and can be viewed in the ISA code viewer window. The simulation controls are available in the main application window. The expression language is available for ALUs and custom components to customize the evaluation of these components.