ISRO2008-55

Question

The Memory Address Register

• A. is a hardware memory device which denotes the location of the current instruction being executed.
• B. is a group of electrical ckt, that performs the intent of instructions fetched from memory
• C. contains the address of the memory location that is to be read from or stored into
• D. contains a copy of the designated memory location specified by the MAR after a "read" or the new contents of the memory prior to a "write"

Answer 1

A MAR  is a CPU register that either stores the memory address from which data will be fetched to the CPU or the address to which data will be sent and stored. Thus, MAR holds the memory location of data that needs to be accessed.

Therefore option C

Comments

@debanjan

option A is also correct

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@asu , I think its Instruction address reg u r talking about .

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Isnt option C and D same?

Answer 2

In a computer, the Memory Address Register (MAR) is a CPU register that either stores the memory address from which data will be fetched to the CPU or theaddress to which data will be sent and stored. In other words, MAR holds thememory location of data that needs to be accessed.

reference::https://en.wikipedia.org/wiki/Memory_address_register

Comments

option (A) is program counter

C will be the answer

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@cse23 That is incorrect. Program Counter holds the address of the next instruction.

Answer 3

Read these meticulously.

• Memory Address Register (MAR) holds the address of the memory location whose data is to be required by the current instruction, or where the data generated by the current instruction will be kept. (OPTION C)
   
• Program Counter (PC) holds the address of the next instruction that is to be fetched.
   
• Instruction Register contains the actual instruction (NOT THE ADDRESS OF IT) that is being executed.