Computer System Architecture MCQ - Central Processing Unit

41 The most appropriate matching for the following pairs

X. Indirect addressing	1. Loops
Y. Immediate addressing	2. Pointers
Z. Auto decrement	3. Constant

In Indirect addressing mode the instruction does not have the address of the data to be operated on, but the instruction points where the address is stored.
In immediate addressing mode the data is to be used is immediately given in instruction it self; so it deals with constant data.
I n Aut o decrement addressing mode, Before determining the effective address, the value in the base register is decremented by the size of the data item which is to be accessed.

42 In serial data transmission, every byte of data is padded with a ‘0’ in the beginning and one or two ‘1’ at the end of byte because

In serial data transmission, every byte of data is padded with a ‘0’ in the beginning and one or two ‘1’ at the end of byte because receiver is to be synchronized for byte reception.

43 Which of the following addressing modes are suitable for program relocation at run time?
1. Absolute addressing
2. Based addressing
3. Relative addressing
4. Indirect addressing

For address relocation we can use Based addressing , Relative addressing modes.

44 Match List-I with List-II and selected the correct answer using the codes given below the lists :

List-I	List-II
A. A[I] = B[J]	1. Indirect addressing
B. while [*A++]	2. Indexed addressing
C. int temp = *x;	3. Autoincrement

Codes :

	A	B	C
a	3	2	1
b	1	3	2
c	2	3	1
d	1	2	3

Correct matching:

1. A[1] = B[J]	Indexed Addressing Mode
2. While [*A++]	Autoincrement
3. int temp = *x;	Indirect Addressing Mode

45 A CPU has 24-bit instructions. A program starts at address 300 (in decimal). Which one of the following is a legal program counter (all values in decimal)?

Size of instruction = 24/8 = 3 bytes.
So Program Counter shift 3 bytes at a time to jump to next instruction.According to that the given options must be divisible by 3. only 600 is satisfied.