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syscall
The controlled doorway a program uses to ask the operating system kernel to do something for it.
User programs can't directly touch hardware or protected memory; instead they make a system call, which traps into the kernel, runs privileged code, and returns. This is how a program opens files, allocates memory, or sends network data. Each CPU architecture has its own trap instruction to trigger it, such as SVC on ARM.
See also
- SVCThe ARM CPU instruction a program runs to ask the operating system kernel for a service.
- stack pointerA CPU register that always points to the top of the current call stack in memory.
- timer tickA regular clock interrupt that lets the operating system periodically take control and switch tasks.
Referenced by
stack pointer · stdint / stddef / stdbool · SVC · TCP · timer tick · TLB