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1.1 Exam Revision - Coggle Diagram
1.1 Exam Revision
Events in the fetch, decode, execute cycle
Decode
4) The MDR now contains either data fetched from memory or an instruction. The control unit DECODES the instruction to see what to do.
Execute
5) The decoded instruction is EXECUTED. This might mean performing a calculation using the ALU, locating some data in memory, changing the program counter value - or something else.
Fetch
1) Each instruction in a computer program is stored in a particular location (or address) in memory. The address of the next instruction is copied from the program counter and placed in the MAR
2) The MAR now contains a memory address. The control unit FETCHES the data that is stored at that address and copies it to the MDR
3) The program counter is incremented to point to the next instruction to be processed in the program for the next cycle
Once the execute part of the cycle is complete, the next fetch, decode, execute cycle begins
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Cache memory is a small area of memory that can accessed quickly. used to store commonly used instructions or data
The CPU provides the instructions and processing power the computer needs to do its work. RAM provides the shorter-term memory the CPU needs to open files and move data around
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