addr, is alias for
Meanwhile full address serialization also include address format tag, workchain,
256bit part ans some additional fields.
Addr, consume from stack two elements: workchain and hash-part and handle this.
All account IDs have 256-bit address in the MasterChain and BaseChain (basic workchain).
Nowadays, only the Masterchain (workchain_id=-1) and occasionally the basic workchain (workchain_id=0) are running in the TON Blockchain.
Both of them have 256-bit addresses, so we henceforth assume that workchain_id is either 0 or -1 and that the address inside the workchain is exactly 256-bit.