// fake code which works similar

extern uint32_t dma_src_address;
extern uint32_t dma_dst_address;
extern uint32_t dma_length;
extenr uint32_t dma_control;
extenr uint32_t dma_status;


void dma_memcpy(void * dst, void const * src, size_t length)
{
    dma_src_address = src;
    dma_dst_address = dst;
    dma_length = length;

    // start the operation here
    dma_control = DMA_START | DMA_INCREMENT_SRC | DMA_INCREMENT_DST;

    while(dma_status & DMA_IN_PROGRESS) {
        /* do stuff here */
        ;
    }
}



// real chip reference:
http://www.keil.com/dd/docs/datashts/nxp/lpc18xx/um10430.pdf
chapter 17: LPC18xx General Purpose DMA (GPDMA) controller (page 349)