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Show 27 "never" (FALSE) transition. This can be of use in debugging by . could not provide a timed transition service, given sufficient knowledge about the PPL elements and the process in which they are implemented. Since SICUDL programs embody no technology dependent information, the simulator implements . timed transitions as being always true. That is, if no other transition is valid at the time tbe transitions from that state are evaluated the timed transition will be taken. To assure even pseudo speed-independent behavior, states with timed transitions should have only that one timed transition from them. Accurate simulation of timed transitions would remove the simulator from the relatively. simple realm of functional simulation and place it in the domain-of detailed· logic simulation. In addition to the "always" (TRUE) transition and in order to complete the notion of boolean expressions as conditions for transi tions and output generation, SICUDL provides the notion of a forcing state-machine execution down a certain path. It has no analog in hardware and is therefore not compiled. Figure 3 is an annotated. sample SICUDL program implementing a machine which is illustrated in figure 2 and which uses most of the constructs defined by the language. Line informs us that the name of the control-unit being specified is "TestAll." Note that the names of the control-unit, state-machines, states, inputs, and outputs can be descriptive. This |
