#CS#Hardware#CPU#Instruction
Instruction Cycle: Fetch-Decode-Execute
How the CPU breathes. This 3-step rhythm repeated billions of times a second is the computer's life.
January 31, 2025
Codemapo
How the CPU breathes. This 3-step rhythm repeated billions of times a second is the computer's life.
Why does my server crash? OS's desperate struggle to manage limited memory. War against Fragmentation.
Two ways to escape a maze. Spread out wide (BFS) or dig deep (DFS)? Who finds the shortest path?
Fast by name. Partitioning around a Pivot. Why is it the standard library choice despite O(N²) worst case?
Establishing TCP connection is expensive. Reuse it for multiple requests.
The biggest insight from studying instruction cycles: "The CPU is dumb, and that's why it's fast."
The CPU doesn't understand context. It can't judge if current work is meaningful or efficient. It just mechanically, insanely fast repeats the given instructions.
Our responsibility as developers is clear: give the CPU good instructions. Reduce unnecessary repetition, arrange data cache-friendly, write code that branch prediction handles well.
Your code is making the CPU dance right now. Fetch-Decode-Execute-Fetch-Decode-Execute... billions of rhythmic beats per second.
Whether that dance is an elegant waltz or chaotic brawl depends entirely on your code.