16. A stack pointer is—

1. 1. A 16-bit register in the _μP that indicates the begining of the stack memory

   
   
   

   2. A register that decodes and executes 16-bit instruction

   
   
   

   3. The first memory location where a sub-routine address is stored

   
   
   

   4. A register in which flag bits are stored.

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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17. When a subroutine is called, the address of instruction following the CALL instruction is stored in/on the—

1. 1. Stack pointer

   
   
   

   2. Accumulator

   
   
   

   3. Program counter

   
   
   

   4. Stack

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: C

   NA

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18. Whenever the POP H instruction is executed—
    

1. 1. Data bytes in HL pair are stored on the stack

   
   
   

   2. Two data bytes at the top of the stack are transferred to the HL register pair

   
   
   

   3. Two data bytes at the top of the stack are transferred to the program counter

   
   
   

   4. Data bytes in pair on stack are transferred to the HL pair

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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19. The instruction RST 7 is a—

1. 1. Restart instruction that begins the execution of a program

   
   
   

   2. One-byte call to the memory address 0038 H

   
   
   

   3. One-byte call to the memory address 0007 H

   
   
   

   4. Hardware interrupt

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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20. If all the ports of 8255 are programmed as O/P ports in mode 1, the CW will be—

1. 1. A 4 H

   
   
   

   2. 84 H

   
   
   

   3. AO H

   
   
   

   4. 80 H

   
   
   

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1. View Hint View Answer Discuss in Forum

   A4 H

   Correct Option: A

   A4 H

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