Term-End Examination
December, 2OO7
CS-64 : INTRODUCTION TO COMPUTER ORGANISATION
Time : 3 hours Maximum Marks : 75
Note : Question number 1 is compulsory. Answer any three questions from the rest.
1. (a) Perform the following arithmetic operations using , 8-bit registers. Use 2's complement method.Indicate overflow/underflow, if any. (6)
(i) - 7 2 - 5 4
(ii) -63+64
(iii) 62 - (-,64)
(iv) 73 + 64
(b) Write an assembly program to reverse a string stored in Data segment. The reversed string should be stored at same location where the original string was stored.(5)
(c) What is the need of micro-programmed control unit in a computer ? How is a micro-program executed ? (4)
(d) What is the need of master-slave flip{lop ? Draw the logic diagram of JK master-slave flip-flop and explains its functioning.(5)
(e) Explain the interrupt driven Input/Output. Compare the operation with DMA. (5)
(f) Explain the use of 'lDIVl and ,AAS' instructions with the heip of an example of each for 8086 micro-processor.(5)
2. (a) Using 4 x 1 multiplexers and full adders; construct a 4-bit arithmetic circuit. With the help of suitable tables, explain how this circuit will perform different arithmetical operations. (6)
(b) Why is memory interleaving used ? Discuss 4-way interleaved memory architecture. (5)
(c) Explain the 2 1/2 D chip organisation. How does it differ from the 2D organisation ?(4)
3. (a) What is the concept of segmentation in the context of 8086 micro-processor ? How is a 16-bit address mapped to 20-bit physical address ? (5)
(b) "ROM is a permanent memory but it is a combinational circuit." Justify this statement by giving example of 2 word-4 bit ROM. How is a cell of ROM different from that of RAM ?(5)
(c) What is an arithmetic processor ? Comp are the co-processor with peripheral processors. (5)
4. (a) List the types of instructions. What are the factors that play an important role for selection of instruction set for a machine ? (5)
(b) Why does DMA have priority over the CPU when both request a memory transfer ?(3)
(c) Make the_ logic diagram of a 4-bit serial shift register using J-K flip-flops. Show the steps to shift the binary number 1001 , through this shift register.(7)
5. (a) Explain four differences between vertical and horizontal micro-instruction formats. (4)
(b) Draw selector and multiplexer l/O channels. Also explain in which situations each would be applied. (4)
(c) If a memory read cycle takes 50 ns and a cache read cycle takes 10 hs, then (using this data) can you prove that the performance with cache is better ? Make ,suitable assumptions about hit ratio. (2)
(d) Write a program for evaluating A + B x C D/E using 2 and 3 address machine instructions (5)