Made Easy Test Series 2024

Question

Consider a CPU where all the instructions require 8 clock cycles to complete execution. There are 220 instructions in the instruction set. It is found that 239 control signals are needed to be generated by the control unit. While designing the horizontal micro-programed control unit, a single address field format is used for branch control logic. What is the minimum size of the control word? (in bits)

Can anyone please explain the concept used here I studied the control unit but I am not getting this question

Answer 1

As there are 220 instructions and each instruction take 8 cycle to execute so total number of cycle is 220×8=1760 cycles.

 No of bit require to handle 1760cycle is log2(1760)=11 bits

As it is horizontal microprogrammed each control signal provide separate bit so, for 239 control signal 239 bit.

So the min size of control word is=239+11=250 bits.

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