0x010xFF

0x010xFF is not a standard single hex literal in most programming languages. It is typically interpreted as a sequence of two hexadecimal bytes: 0x01 and 0xFF. Such a two-byte sequence can represent a 16-bit quantity when considered as a single value, or it can be used as two separate fields within a binary format.

If interpreted as a 16-bit unsigned integer in big-endian (network) order, the value of the two-byte sequence 01 FF is 0x01FF, which equals 511 in decimal. In little-endian order, the same two bytes would represent 0xFF01, equal to 65281 in decimal. This illustrates how endianness affects the interpretation of byte sequences.

In practical contexts, a two-byte sequence like 0x01 and 0xFF may appear in binary protocols, file formats, or memory dumps as a length field, a flag pair, or a compact numeric value. For example, some protocols reserve 0x01 as a version or control indicator and 0xFF as a maximum or sentinel, with the combined bytes encoding a specific small integer in big-endian form.

In character encodings, 0x01 is a control code (Start of Header in ASCII), while 0xFF corresponds to a non-ASCII character in ISO-8859-1 but has no independent meaning in UTF-8 without accompanying bytes. Therefore, a standalone pair 01 FF is not meaningful as text.

Because 0x010xFF mixes two hex literals, it is typically a documentation shorthand or a typographical quirk rather than a formal notation. When documenting data formats, it is clearer to write 0x01 0xFF or 01 FF.