List the step needed to execute the machine instruction
Load R2, LOC
The required steps are:
- Send the address of the instruction word from the register PC to the memory and issue a Read control command.
- Wait until the requested word has been retrieved from the memory, then load it into register IR, where it is interpreted (decoded) by the control circuitry to determine the operation to be performed.
- Increment the contents of the register PC to point to the next instruction in memory.
- Send the address value LOC from the instruction in register IR to the memory and issue a Read control command.
- Wait until the requested word has been retrieved from the memory, then load it into register R2.
List the step needed to execute the machine instruction
Add R3, R2, R1
The required steps are:
- Transfer the contents of the register PC to register MAR.
- Issue a Read command to memory, and then wait until it has transferred the requested word into register MDR.
- Transfer the instruction from MDR into IR and decode it.
- Transfer contents of R1 and R2 to the ALU.
- Perform the addition of two operands in the ALU and transfer the answer into R3.
- Transfer contents of PC to ALU.
- Add 1 to an operand in ALU and transfer incremented address to PC.
List the step needed to execute the machine instruction
STORE R4, LOC
The required steps are:
- Send the address of the instruction word from the register PC to the memory and issue a Read control command.
- Wait until the requested word has been retrieved from the memory, then load it into register IR, where it is interpreted (decoded) by the control circuitry to determine the operation to be performed.
- Increment the contents of the register PC to point to the next instruction in memory.
- Send the address value LOC from the instruction in register IR to the memory and issue a Read control command.
- Wait until the requested word has been retrieved from the memory, then store it in register R4.
