Draw the instruction word format and indicate the number of bits in each part



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Chapter 5

#13 A computer uses a memory unit 256k words of 32 bits each. A binary instruction code is stored in one word of memory. The instruction has four parts : indirect bit , an operation code , a register code part to specify one of 64 registers, and an address part.



  1. How many bits are there in the operation code , the register code part , and the address part?

  2. Draw the instruction word format and indicate the number of bits in each part.

  3. How many bits are there in the data and address inputs of the memory?

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#14 What is the difference between a direct and an indirect address instruction?

How many references to memory are needed for each type of instruction to bring an operand into a processor register?

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#15 What are the two instructions needed in the basic computer in order to set the E flip–flop to 1?

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#16 Draw a timing diagram similar to fig 5-7(refer morris mano) assuming that SC is cleared to 0 at time T3 if control signal C7 is active.

C7T3 : SC←0

C7 is activated with the positive clock transition associated with T1.

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Chapter 8

#17 A bus – organized CPU has 16 registers with 32 bits in each , an ALU , and a destination decoder.


  1. How many multiplexers are there in the A bus , and what is the size of each multiplexer?

  2. How many selection inputs are needed for mux A and mux B?

  3. How many inputs and outputs are there in the decoder?

  4. How many inputs and outputs are there in the ALU for data, including input and output carries?

  5. Formulate a control word for the system assuming that the ALU has 35 operations.

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#18 Specify the control word that must be applied to the processor of fig 8-2(refer morris mano) to implement the following microoperations



  1. R1 ← R2 +R3

  2. R4 ← R4

  3. R5 ← R5 – 1

  4. R6 ← shl R1

  5. R7 ← input

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#19 Convert the following arithmetic expressions from infix to reverse polish notation.



  1. A*B + C*D + E*F

  2. A*B+A*(B*D + C*E)

  3. A + B *[(C*D + E*(F +G)]

  4. A*[B +C * (D +E)]

F* (G +H)

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#20 Convert the following arithmetic expressions from reverse polish notation to infix polish notation.


  1. A B C D E +*-/

  2. A B C D E */-+

  3. A B C D E F G +*+*+*

  4. A B C */D – E F /+

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#21 A computer has 32-bit instructions and 12-bit addresses.If there are 250 two address instructions, how many one – address instruction can be formulated ?

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#22 Write a program to evaluate the arithmetic statement:



X= A – B + C * (D*E – F)

G + H *K


  1. Using a general register computer with three address instructions.

  2. Using a general register computer with two address instructions.

  3. Using an accumulator type computer with one address instructions.

  4. Using a stack organized computer with zero-address operation instructions.

#23 A two-word instruction is stored in memory at an address designated by the symbol W. The address field of the instruction (stored at W +1 ) is designated by the symbol Y . the operand used during the execution of the instruction is stored at an address symbolized by z. An index register containsthe value X. State how Z is calculated from other addresses if the addressing of the instruction is

  1. Direct

  2. Indirect

  3. Relative

  4. Indexed

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#24 A relative mode branch type of instruction is stored in memory at an address equivalent to decimal 750 . the branch is made to an address equivalent to decimal 500.



  1. What should be the value of the relative address field of the instruction (in decimal)?

  2. Determine the relative address value in binary using 12 bits .(why must the number be in 2’s complement?)

  3. Determine the binary value in PC after the fetch phase and calculate the binary value of 500. Then show that the binary in PC plus the relative address calculated in part b is equal to the binary value of 500.

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#25 An instruction is stored at location 300 with its address field at location 301 . the address field has the value 400 . A processor register R1 contains the number 200. Evaluate the effective address if the addressing mode of the instruction is (a) direct (b) immediate (c)relative (d) register indirect (e) index with R1 as the index register.



Chapter -9

#26 In certain scientific computations it is necessary to perform the arithmetic operation (Ai +Bi)(Ci + Di) with a stream of numbers . Specify a pipeline configuration to carry out this task . List the contents of all registers in the pipeline for i=1 through 6.

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#27 Draw a space-time diagram for a six-segment pipeline showing the time it takes to process eight tasks.

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#28 Determine the number of clock cycles that it takes to process 200 tasks in a six-segment pipeline.

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#29 The nonpipeline system takes 50 ns to process a task . the same task can be processed in a six – segment pipeline with clock cycle of 10ns . Determine the speedup ratio of the pipeline for 100ns task . what is the maximum speedup that can be achieved?

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#30 consider the four instructions in the following program . suppose that the first instruction starts from step 1 in the pipeline used in fig 9-8 . specify what operation are performed in the four segments during step 4.

Load R1 ← M[312]

ADD R2 ← R2 + M[313]

Inc R3 ← R3 +1

Store M[314] ← R3

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#31 Give an Example that uses delayed load with the three-segment pipeline of sec 9-5 (refer morris mano)

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#32 Consider the multiplication of two 40 ×40 matrices using a vector processor .

  1. How many product terms are there in each inner product , and how many inner products must be evaluated?

  2. How many multiply-add operations are needed to calculate the product matrix?

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#33 Show the contents of registers E,A,Q and SC (as in fig 10-12, refer morris mano) during the process of multiplication of two binary numbers ,11111 (multiplicand) and 10101 (multiplier) .the signs are not included.

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#34 Why should the sign of the remainder after a division be the same as the sign of the dividend ?

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#35 Show the contents of registers E,A,Q and SC (as in fig 10-12, refer morris mano) during the process of division of (a) 10100011 by 1011; (b) 00001111 by 0011.(use a dividend of eight bits.)



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