ASYNC_HEADER_Q0_PRIORITY_MASK
header[0] &= ~ASYNC_HEADER_Q0_PRIORITY_MASK;
header[0] |= (((u32)priority) << ASYNC_HEADER_Q0_PRIORITY_SHIFT) & ASYNC_HEADER_Q0_PRIORITY_MASK;
return (header[0] & ASYNC_HEADER_Q0_PRIORITY_MASK) >> ASYNC_HEADER_Q0_PRIORITY_SHIFT;