Function validate_mask_write_address 

pub fn validate_mask_write_address(address: u16) -> Result<(), ExceptionCode>

Validate a mask write register (FC 16) address.

Per spec §6.16 Figure 26 — both AND and OR mask values accept 0x0000–0xFFFF. Only the address is validated at the protocol level.

Errors

• IllegalDataAddress if address is not valid (overflows with quantity 1)