调试stm8s105的时候，如何在中断向量表中设置自己的中断？

各位大大，我在调试stm8s105的时候，如何在中断向量表中设置自己的中断？我做的是一个旋转编码按键，PC4位中断输入，external_Interrupt应该放到什么位置？
我看别人的程序：tiM4对应/*irq23*/，TLI对应/*irq0*/。

typedef void @far (*interrupt_handler_t)(void);

struct interrupt_vector {
        unsigned char interrupt_instruction;
        interrupt_handler_t interrupt_handler;
};

@far @interrupt void NonHandledInterrupt (void)
{
        /* in order to detect unexpected events during development,
           it is recommended to set a breakpoint on the following instruction
        */
        return;
}

extern void _stext();     /* startup routine */

struct interrupt_vector const _vectab[] = {
        {0x82, (interrupt_handler_t)_stext}, /* reset */
        {0x82, NonHandledInterrupt}, /* trap  */
        {0x82, NonHandledInterrupt}, /* irq0  */
        {0x82, NonHandledInterrupt}, /* irq1  */
        {0x82, NonHandledInterrupt}, /* irq2  */
        {0x82, NonHandledInterrupt}, /* irq3  */
        {0x82, NonHandledInterrupt}, /* irq4  */
        {0x82, NonHandledInterrupt}, /* irq5  */
        {0x82, NonHandledInterrupt}, /* irq6  */
        {0x82, NonHandledInterrupt}, /* irq7  */
        {0x82, NonHandledInterrupt}, /* irq8  */
        {0x82, NonHandledInterrupt}, /* irq9  */
        {0x82, NonHandledInterrupt}, /* irq10 */
        {0x82, NonHandledInterrupt}, /* irq11 */
        {0x82, NonHandledInterrupt}, /* irq12 */
        {0x82, NonHandledInterrupt}, /* irq13 */
        {0x82, NonHandledInterrupt}, /* irq14 */
        {0x82, NonHandledInterrupt}, /* irq15 */
        {0x82, NonHandledInterrupt}, /* irq16 */
        {0x82, NonHandledInterrupt}, /* irq17 */
        {0x82, NonHandledInterrupt}, /* irq18 */
        {0x82, NonHandledInterrupt}, /* irq19 */
        {0x82, NonHandledInterrupt}, /* irq20 */
        {0x82, NonHandledInterrupt}, /* irq21 */
        {0x82, NonHandledInterrupt}, /* irq22 */
        {0x82, NonHandledInterrupt}, /* irq23 */
        {0x82, NonHandledInterrupt}, /* irq24 */
        {0x82, NonHandledInterrupt}, /* irq25 */
        {0x82, NonHandledInterrupt}, /* irq26 */
        {0x82, NonHandledInterrupt}, /* irq27 */
        {0x82, NonHandledInterrupt}, /* irq28 */
        {0x82, NonHandledInterrupt}, /* irq29 */
};