ASYNC_HEADER_Q3_EXTENDED_TCODE_MASK
header[3] &= ~ASYNC_HEADER_Q3_EXTENDED_TCODE_MASK;
header[3] |= (((u32)extended_tcode) << ASYNC_HEADER_Q3_EXTENDED_TCODE_SHIFT) & ASYNC_HEADER_Q3_EXTENDED_TCODE_MASK;
return (header[3] & ASYNC_HEADER_Q3_EXTENDED_TCODE_MASK) >> ASYNC_HEADER_Q3_EXTENDED_TCODE_SHIFT;