stm8 dma interrupt

INTERRUPT_HANDLER(DMA1_CHANNEL2_3_IRQHandler,3)
{
    static uint8_t i=0;
  extern uint8_t dac_buf[4][dac_buf_size/4];
  extern uint8_t half_buf;

    GPIOA->ODR|=(uint8_t)(GPIO_Pin_4);

    //remaining half of last buf part, 64 bytes
    if ((DMA1_Channel3->CSPR & DMA_CSPR_HTIF)&&(i==3))
    half_buf=1;

    if (DMA1_Channel3->CSPR & DMA_CSPR_TCIF) {//if bufpart ended
        DMA1_Channel3->CCR &= (uint8_t)(~DMA_CCR_CE);//dma disable
      DMA1_Channel3->CM0ARH = (uint8_t)((uint16_t)&(dac_buf[i]) >> (uint8_t)8);
        DMA1_Channel3->CM0ARL = (uint8_t)((uint16_t)&(dac_buf[i]));
        DMA1_Channel3->CNBTR=dac_buf_size/4;
        DMA1_Channel3->CCR |= (uint8_t)(DMA_CCR_CE);//dma enable
        i++;
        i&=0x03;
    }

  DMA1_Channel3->CSPR&=(uint8_t)(~(DMA_CSPR_TCIF|DMA_CSPR_HTIF));

    GPIOA->ODR&=(uint8_t)(~GPIO_Pin_4);
}