Classical

Computer Organization Architecture - Machine instructions and addressing modes

21:  

The addressing mode used in the instruction PUSH B is

A.

Direct

B.

Register

C.

Register indirect

D.

Index

 
 

Option: B

Explanation :

Push is used to write into stack 
1. This is not direct we are not mentioning address here. 
2. It's not register indirect we are not mentioning register which contain address.
3. It's not immediate we are not storing immediate value. 
So answer is (B) i.e. register addressing


22:   The process of fetching and executing instructions,one at a time, in order of increasing addreses is called
A. Instruction execution
B. Straight line sequencing
C. Instruction fetch
D. Instruction Cycle
 
 

Option: B

Explanation :


23:   The CPU of a Computer takes instruction from the memory and executes them. This process is called
A. Load cycle
B. Time sequence
C. Fetch-execute cycle
D. None of these
 
 

Option: C

Explanation :


24:   When a program is being executed in an 8085 microprocessor, its Program Counter contains
A. Number of instructions in the current program that have already been executed
B. The total number of instructions in the program being executed
C. Memory address of the instruction that is being currently executed
D. Memory address of the instruction that is to be executed next
 
 

Option: D

Explanation :


25:   When the HLT instruction of a 8085 micro-processor is executed, the microprocessor
A. Is disconnected from the system bus till the reset is pressed
B. Halts execution of the program and returns to monitor
C. Enters into a halt state and the buses are tri- stated
D. Reloads the program form the locations 0012 and 0013 H.
 
 

Option: C

Explanation :




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