// revU64 returns the given uint64 u with bytes in the reverse order.
//go:inline
revU64 returns the given uint64 u with bytes in the reverse order.
go:inline
// revU64 returns the given uint64 u with bytes in the reverse order . // go : inline
func revU64(u uint64) uint64 {
	if u == 0 {
		return 0
	}
	return ((u & 0x00000000000000FF) << 56) |
		((u & 0x000000000000FF00) << 40) |
		((u & 0x0000000000FF0000) << 24) |
		((u & 0x00000000FF000000) << 8) |
		((u & 0x000000FF00000000) >> 8) |
		((u & 0x0000FF0000000000) >> 24) |
		((u & 0x00FF000000000000) >> 40) |
		((u & 0xFF00000000000000) >> 56)
}
func revU64 ( u uint64 ) uint64 { if u == 0 { return 0 } return ( ( u & 0x00000000000000FF ) << 56 ) | ( ( u & 0x000000000000FF00 ) << 40 ) | ( ( u & 0x0000000000FF0000 ) << 24 ) | ( ( u & 0x00000000FF000000 ) << 8 ) | ( ( u & 0x000000FF00000000 ) >> 8 ) | ( ( u & 0x0000FF0000000000 ) >> 24 ) | ( ( u & 0x00FF000000000000 ) >> 40 ) | ( ( u & 0xFF00000000000000 ) >> 56 ) }
revU64 returns the given uint64 u with bytes in the reverse order.
revU64 returns the given uint64 u with bytes in the reverse order .
// skip all processing for the common case (u = 0)