Layout of Call Data

The input data for a function call is assumed to be in the format defined by the ABI specification. Among others, the ABI specification requires arguments to be padded to multiples of 32 bytes. The internal function calls use a different convention.

Arguments for the constructor of a contract are directly appended at the end of the contract’s code, also in ABI encoding. The constructor will access them through a hard-coded offset, and not by using the codesize opcode, since this of course changes when appending data to the code.