How is ZydisDecodedOperand.imm.is_signed determined?

[McSinyx]

When Zydis encounter an immediate like $0x8877665544332211, what hint can be given to mark it as signed or is it determined based on the instruction?

[mappzor]

Every instruction definition contains information about physical encoding of its operands. During decoding that information is extracted from the definition and passed to the user as ZydisDecodedOperand.encoding. See docs for possible values.

[McSinyx]

Thanks!