IT Services Circle

May 9, 2026 · Fundamentals

What Your CPU Actually Does All Day: The Four Core Tasks

The article explains that a CPU continuously repeats four stages—fetch, decode, execute, and write‑back—while highlighting the role of registers, the differences between CISC and RISC instruction sets, how function calls build and tear down stack frames, and why user‑mode coroutines are far lighter than kernel threads.