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mkbh_10
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What does the FETCH EXECUTE OVERLAP instruction mean ?
berkeman said:It just looks like the execute of the current instruction is overlapped a bit with the fetching of the next instruction:
http://www.geocities.com/siliconvalley/peaks/3938/z80arki.htm
The FETCH-EXECUTE overlap cycle is a fundamental concept in computer science that explains the process of executing instructions in a computer's central processing unit (CPU). It involves fetching an instruction from memory, decoding it, and executing it while simultaneously fetching the next instruction. This allows for efficient use of the CPU's time and resources.
During the FETCH-EXECUTE overlap cycle, the CPU's instruction pointer fetches an instruction from memory and sends it to the instruction decoder. The decoder then interprets the instruction and sends it to the appropriate part of the CPU to be executed. While the instruction is being executed, the instruction pointer simultaneously fetches the next instruction from memory. This process continues in a continuous cycle, allowing for efficient execution of instructions.
The FETCH-EXECUTE overlap cycle is important because it allows for efficient use of the CPU's resources. By overlapping the fetching and executing of instructions, the CPU can minimize the time it spends waiting for instructions to be fetched, leading to faster and more efficient processing.
Yes, the FETCH-EXECUTE overlap cycle can be interrupted if the CPU receives a higher-priority instruction, such as an interrupt request. In this case, the current instruction being executed will be paused, and the interrupt will be handled before returning to the FETCH-EXECUTE cycle.
One potential issue with the FETCH-EXECUTE overlap cycle is the possibility of data hazards, where the instructions being executed depend on the results of previous instructions. This can lead to incorrect results if not properly managed. Another potential issue is branch prediction, where the CPU has to guess which instruction will be executed next in order to maintain the overlap cycle, which can sometimes result in incorrect predictions and inefficiency.