0x01000x01FF

0x01000x01FF is a nonstandard string that combines two hexadecimal literals with an internal separator. In conventional hex notation, numbers begin with 0x and consist solely of the digits 0–9 and the letters A–F. The substring 0x01000 corresponds to the decimal value 4096, while 0x01FF corresponds to 511. However, the full form 0x01000x01FF does not denote a single numeric value and is not recognized as valid hexadecimal syntax in typical programming languages.

Interpreting the string depends on context. It is sometimes encountered in documentation or examples as a concatenation of two values, rather than a single value. Some authors might intend to indicate a range or pair of related identifiers, for example a start value 0x01000 and an end value 0x01FF, though standard range notation would use 0x01000-0x01FF or a similar explicit format. In other cases, the string may be used as a mnemonic or obfuscated identifier in security research or proprietary protocols, where the exact meaning is defined by the surrounding system.

Common interpretations include treating it as two separate hex values, a range indicator, or a context-specific identifier. Without additional information, the string remains ambiguous. When documenting or parsing such notation, it is advisable to clarify the intended meaning and adopt a standard representation to avoid confusion, such as using separate fields for the two values or a clearly stated range syntax. See also hex notation, memory addresses, and opcode encoding.