typedef unsigned int uint32_t;
typedef unsigned char uint8_t;

void foo (uint32_t *src, uint8_t *c, uint32_t bytes)
{
  uint8_t *ctarget;

  for (;;) {
    c[0] = src[0] & 0xff;

    if (bytes <= 8) {
      if (bytes < 8) {
	 ctarget[4] = c[4];
      }
      return;
    }

    bytes -= 8;
    c += 8;
  }
}