0xFE

0xFE is a hexadecimal notation for the byte value 254. It is written with the two hex digits F and E. In binary, 0xFE is 11111110. As an unsigned 8-bit value it ranges from 0 to 255; as a signed 8-bit value, 0xFE represents -2 in two’s complement.

In programming, 0xFE is often used as a bitmask to clear the least significant bit. For example, performing a bitwise AND with 0xFE yields a value with the least significant bit set to zero, which is a common operation in low-level data processing.

In text encodings, 0xFE is outside the ASCII range. In ISO/IEC 8859-1 and Windows-1252, 0xFE maps to the Latin small letter thorn, þ (U+00FE). This character is not part of standard ASCII but appears in extended single-byte encodings.

In the Ethereum Virtual Machine (EVM), 0xFE is defined as an invalid opcode. If encountered during execution, it causes an invalid opcode exception. This is distinct from 0xFF, which is used for the SELFDESTRUCT operation in the EVM.

Overall, 0xFE functions as a high-value byte in many contexts, with uses ranging from a practical bitmask in software to a defined meaning in certain encoding schemes and execution environments. Its interpretation is context-dependent and can vary across hardware, software, and protocols.