examples of software systems, which implement their control by storing an encoded version of it in a memory. We will continue with multiplication as an. example, since we have already produced an extensive analysis of hardwired versions. All of the software systems belong within the RT-level design domain. None has an instruction that simply evokes a multiplication operation; hence for each multiplication must be programmed. We will not be concerned here with the internal hardware structure of these software systems. Chapter 6 is devoted to computers and the systems used here are all analyzed in detail there. We take the software systems as given, and examine how they perform multiplication.

K(PCS\PROGRAMMABLE COMMAND SEQUENCER)

The K(PCS\Programmable Command Sequencer) was introduced in Chapter 2 as an available RTM control module. It provides a general scheme to control RTM's from a memory rather than from a hardwired control part. The discussion there and in Chapter 6 provides a description of the. encoding and gives the details of the module's internal operation.

Fig. 26. Table of K(Programmable Control Sequencer) cost and performance.

With K(PCS) additional time is required to fetch the encoded control steps from memory, giving the longer operations times shown in the table of Figure 26. Costs are also given in the table, assuming that all the words of the memory are

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