JNTU IV B.Tech I Semester Supplimentary Examinations, February 2008

JNTU IV B.Tech I Semester Supplimentary Examinations, February 2008





1. (a) Distinguish between multiplication of unsigned integers and 2’s complement integers.

(b) Express the given numbers in I E E E 32-bit floating-point format.

i. 836.5

ii. 1025.75


2. Explain clearly the following with neat diagrams:

(a) Data Flow in fetch cycle,

(b) Data Flow in indirect cycle and

(c) Data Flow in interrupt cycle.


3. (a) Explain the following instructions with respect to function,T-states, machine cycles, and addressing mode:

i. XCHG.

ii. SIM

iii. OUT port address.

iv. POP rp

(b) Write a program for 8085 processor to pick up maximum among a set of n

numbers stored in memory.

(c) Which instruction uses AC flag in 8085 ? Can the programmer be allowed to manipulate this flag ?


4. Consider an accumulator based CPU with the following eight one address instructions. LOAD X, STORE X, ADD X, AND X, JMP X, JMPZ X, CMPL, (Complement Accumulator), and RSHIFT. Give fetch and execute cycle operations and identify the necessary control signals to be generated for the above instructions by a micro programmed control unit.


5. Explain the one dimensional and two dimensional RAM organizations in detail:


6. Explain the follwoing in detail:

(a) Cache types

(b) Performance of Cache memory.


7. (a) What is the difference between memory mapped I/O and isolated I/O? What are the advantages and disadvantages of each?

(b) What are the advantages of using interrupt-initiated data transfer over the transfer under program control without an interrupt?


8. (a) Differentiate between programmed I/O and memory mapped I/O.

(b) Compare interrupt I/O control with DMA I/O control. Why does DMA have priority over CPU when both requests a memory transfer?


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