SEEK_COMPLETE
if (swim3_readbit(fs, SEEK_COMPLETE))
ret = swim3_readbit(fs, SEEK_COMPLETE) == 0
if (swim3_readbit(fs, SEEK_COMPLETE)) {
if (n >= HZ/30 && swim3_readbit(fs, SEEK_COMPLETE))
if (err == 0 && (swim3_readbit(fs, SEEK_COMPLETE) == 0