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Show 36 the case of a FORK) is made active, then the current state (or in the case of a join, the current states) are made inactive. Outputs which are controlled by transitions are changed concurrently with the . activation of the next state(s) • the activity or inactivity of predecessor states. The change to Semantically, SICUDL is quite easy to understand. This simplicity of SICUDL semantics leads to readily understood control-unit. operation and the relatively easy implementation of a funct1.onal simulator. Compilation of alternate semantic interpretations of SICUDL programs into PPL programs is not significantly more difficult. For example, compilation of an asynchronous semantic interpretation of SICUDL would only require altering transitions to occur regardless of asynchronous speed-independent control-units would, however, make accurate control-unit simulation much more difficult. Functional Simulation Utility Futility The functional simulation of SICUDL, as stated above, is quite easy. The speed-independent nature of the problem solution e1inates the detailed timing analysis which would be necessary in simUlating an asynchronous system which was not speed-independent. While functional simulation can not provide detailed timing analysis and therefore can not yield any accurate estimate of circuit speed, it does provide verification of correct sequential interaction of the circuit with the eironment in which it will be located. The sililulation -algorithm may be basically summarized as follows. The notion of time in simulating SICUDL is reduced to a knowledge of |
