Vectortabelle

A vectortabelle, or vector table, is a data structure used in computer systems to map event types such as interrupts or exceptions to the memory addresses of their corresponding handler routines. It acts as a dispatch table that lets the system transfer control to the appropriate code in response to asynchronous events or system events. While the term is most common in embedded and real-time contexts, similar concepts appear in other software domains as jump or dispatch tables.

In microcontroller and processor architectures, the vector table is typically located in non-volatile memory at a fixed or configurable base address. On ARM Cortex-M devices, the table is an array of 32-bit words containing the addresses of handlers. The first entry holds the initial stack pointer, the second the Reset_Handler, and subsequent entries correspond to NMI, HardFault, and then the various peripheral interrupt handlers. The CPU uses the table automatically when an interrupt occurs. Some architectures allow relocating the table at runtime via a vector table offset register (such as VTOR on ARM Cortex-M), enabling features like multi-application systems or bootloaders.

The size and exact layout depend on the device and its interrupt set. Each entry is typically a pointer to a function with a standard signature. The vector table is usually defined in startup code and placed in a dedicated memory section, with the linker configured to place it at the required address.

Beyond embedded systems, the term is used more broadly for dispatch structures that route events to handlers in software, such as interrupt descriptor tables, jump tables, or event dispatch mechanisms in various domains.