COMPUTER SCIENCE AND ENGINEERING
COMPUTER ARCHITECTURE
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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The Data is returned from memory into the MDR
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The MAR is sent to memory along the address bus
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The instruction in the CIR is decoded
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The data in the Accumulator is copied into the MDR
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Detailed explanation-1: -The process copies the program counter into the memory address register and calls the procedure. When the procedure returns, the process copies the data from the memory data register, placed there by the procedure, to the instruction register.
Detailed explanation-2: -The address in the CPU is passed to the Memory Address Register. The address in the Memory Address Register is passed to RAM so the contents of that memory address can be accessed.
Detailed explanation-3: -memory address register (MAR)-holds the address of the current instruction that is to be fetched from memory, or the address in memory to which data is to be transferred. memory data register (MDR)-holds the contents found at the address held in the MAR, or data which is to be transferred to main memory.
Detailed explanation-4: -Eventually, the instruction in the MDR is copied into the current instruction register (CIR) which acts as a temporary holding ground for the instruction that has just been fetched from memory. During the decode stage, the control unit (CU) will decode the instruction in the CIR.