Urgent: sdram to flash

How to write 1Mb of data, let's say all '0' from sdram to flash? I know how to transfer like 100 digits but I am stuck when I tried to transfer 1Mb of data. When I try to transfer 1Mb of data, it seems like stuck during writing into flash. I am using de2 board with 8mb sdram and 4mb flash.

--- Quote Start ---

# include <stdio.h># include <stdlib.h># include "system.h"# include "alt_types.h"# include "sys/alt_dma.h"# include "sys/alt_flash.h" # include "sys/alt_flash_dev.h"

# define size 1048576

int main ()

{

int rc;

alt_flash_fd* fd;

int ret_code, i;

int source;

int dest;

//printf("Source\tDest:\n");

for(i=0;i<size;i++)

{

source = i;

dest = 0;

}

printf("%d\t%d\n", source, dest);

printf("Final\n\n");

fd = alt_flash_open_dev(EXT_FLASH_NAME);

if (fd!=NULL)

{

if((ret_code = alt_write_flash(fd, 0, source, 1048576)) == 0)

{

if((ret_code = alt_read_flash(fd, 0, dest, 1048576)) == 0)

{

printf("%d\t%d\n", source, dest);

}else

{

printf("Error in reading from flash\n");

}

}else

{

printf("Error in writing to flash\n");

}

}else

{

printf("Error in opening flash\n");

exit(1);

}

return 0;

}

--- Quote End ---

It stucks here:

--- Quote Start ---

nios2-terminal: connected to hardware target using JTAG UART on cable

nios2-terminal: "USB-Blaster [USB-0]", device 1, instance 0

nios2-terminal: (Use the IDE stop button or Ctrl-C to terminate)

--- Quote End ---