COMPUTER SCIENCE AND ENGINEERING
COMPUTER ARCHITECTURE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Memory data register
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Memory address register
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Accumulator
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Current instruction register
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Detailed explanation-1: -Which of the following holds the last instruction fetched? Explanation: The IR which stands for the instruction register contains the last instruction fetched. All the others options are registers which are used for the fetch operation.
Detailed explanation-2: -To execute an instruction, the processor copies the instruction code from the program memory into the instruction register (IR). It can then be decoded (interpreted) by the instruction decoder, which is a combinational logic block which sets up the processor control lines as required.
Detailed explanation-3: -The program counter (PC) is a special register that holds the memory address of the next instruction to be executed.
Detailed explanation-4: -current instruction register (CIR) A register, usually in the control unit, that contains the information specifying the instruction that is being (or is about to be) performed.