Question

HOLD and HLDA (Hold Acknowledge) of 8086 microprocessor signals are used to enable 

• (DMA (Direct Memory Access 

• Odd bank memory

• I/O 

• Even bank memory 

Which of the following is not a data copy/transfer instruction 

• DAS 

• PUSH 

• POP 

• MOV

Answer 1

6. Option A

HOLD(input) - indicates that another master is requesting the use of the address and data bus. The CPU, upon receiving the HOLD request, will relinquish the use of buses as soon as the completion of the current machine cycle.

HLDA(output) -hold acknowledge indicates that the CPU has received the HOLD request and that it will relinquish the buses in the next clock cycle.

Both the signals are for Direct memory access.

7. Option A

POP-Used to get a word from the top of the stack to the provided location.

PUSH-Used to put all the registers into the stack.

MOV-Used to copy the byte or word from the provided source to the provided destination.

These are used to copy/transfer data.

DAS-Used to adjust decimal after subtraction.

So this is not for copy or transfer data.