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How Microprocessors Work

Step 4: Push Key =

When you press the "=" key, the Prefetch Unit once again checks the Instruction Cache for an instruction for the new data, which it doesn't find.

The instruction for "=" comes into the microprocessor from the computer's main memory through the Bus Unit and gets stored in an Instruction Cache address as the code "Print Z."

Microprocessor Diagram

The Prefetch Unit then asks the Instruction Cache for a copy of the code "Print Z" and sends it to the Decode Unit for further processing.

In the Decode Unit, the instruction "Print Z" is translated or decoded into a string of binary code that is sent off to the Control Unit to tell it what to do with the instruction.

Microprocessor Diagram

Now that the value of Z has been computed, and is residing in register file entry #5, the print command has only to retrieve register 5's contents and display them to a screen so you can finally see the sum of 2+3. The microprocessor has completed its task for you.

Microprocessor Diagram

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