: It manages events where hardware devices try to access system memory via Direct Memory Access ( DMA ).
In simpler terms: When a hardware interrupt fires (e.g., a timer, UART, or GPIO edge), the CPU jumps to a predefined address in the . Typically, that table entry holds a jump to a generic assembly stub, which eventually calls a high-level C function—often named ivthandleinterrupt —to decode the interrupt source and execute the appropriate callback. ivthandleinterrupt
The CPU saves minimal context (often just PC and status register) and loads the Program Counter from the . The base address of the IVT is usually stored in a CPU-specific register (e.g., VTOR on ARM, IDTR on x86). : It manages events where hardware devices try
), analyze it (using tools like WinDbg) to find the specific driver causing the violation. The CPU saves minimal context (often just PC
The path through ivthandleinterrupt adds latency between the hardware event and the user ISR. On a 100 MHz Cortex-M4, each additional function call plus the dispatcher logic might cost 100–200 ns. For high-speed interrupts (e.g., 1 MHz PWM feedback), this is unacceptable. In such cases, engineers bypass the generic dispatcher and install a direct ISR in the IVT.
The moment an interrupt occurs, the CPU stops what it’s doing. ivthandleinterrupt ensures the current "context" (registers, program counter, and flags) is pushed onto the stack.