CPU control design and Interfaces

Question 21

Which interrupt in 8085 Microprocessor is unmaskable?

• RST 5.5
• RST 7.5
• TRAP
• Both (a) and (b)

Question 22

A cache memory needs an access time of 30 ns and main memory 150 ns, what is the average access time of CPU (assume hit ratio = 80%)?

• 60
• 30
• 150
• 70

Question 23

Match the following :

• (1)
• (2)
• (3)
• (4)

Question 24

How many 32K X 1 RAM chips are needed to provide a memory capacity of 256K-bytes?

• 8
• 32
• 64
• 128

Question 25

The register that stores the bits required to mask the interrupts is ______.

• Status register
• Interrupt service register
• Interrupt mask register
• Interrupt request register

Question 26

In ______ addressing mode, the operands are stored in the memory. The address of the corresponding memory location is given in a register which is specified in the instruction.

• Register direct
• Register indirect
• Base indexed
• Displacement

Question 27

In the case of parallelization, Amdahl’s law states that if P is the proportion of a program that can be made parallel and (1 - P) is the proportion that cannot be parallelized, then the maximum speed-up that can be achieved by using N processors is:

• 
• 
• 
• 

Question 28

In which addressing mode, the effective address of the operand is generated by adding a constant value to the content of a register?

• Absolute mode
• Indirect mode
• Immediate mode
• Index mode

Question 29

Which of the following is/are true of the auto-increment addressing mode? I. It is useful in creating self-relocating code II. If it is included in an Instruction Set Architecture, then an additional ALU is required for effective address calculation III. The amount of increment depends on the size of the data item accessed

• I only
• II only
• III only
• II and III only

Question 30

Consider the following Assembly language program

MVIA   30 H
ACI    30 H
XRA    A
POP    H

After the execution of the above program, the contents of the accumulator will be

• 30 H
• 60 H
• 00 H
• contents of stack