◄ Wiki / OS
CNTP
ARM's built-in hardware timer that counts real elapsed time, used during boot and scheduling.
ARM CPUs include an architectural counter-timer, and CNTP is the physical timer part of it — a steadily incrementing counter the OS reads to measure time and schedule interrupts. Early boot code needs it to set up timekeeping before higher-level services exist. It is the ARM equivalent of relying on a known, spec-defined clock source.
See also
- bootloader / mzBIOSThe very first code that runs when a machine powers on, whose job is to wake the hardware and hand control to the operating system.
- context switchThe kernel saving one thread's full state and loading another's, so a single CPU can juggle many tasks.
- CPU exception / trapThe CPU automatically jumping into special handler code when something like a fault or error occurs.