1. A computer program product for executing a load instruction for loading data from an adapter, said computer program product comprising: a computer readable storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising: obtaining a machine instruction for execution, the machine instruction being defined for computer execution according to a computer architecture, the machine instruction comprising: an opcode field identifying a load from adapter instruction; a first field identifying a first location at which data fetched from an adapter will be loaded; a second field identifying a second location, the contents of which include a function handle identifying the adapter, a designation of an address space within the adapter from which data is to be loaded, and an offset within the address space; and executing the machine instruction, the executing comprising: using the function handle to obtain a function table entry associated with the adapter; obtaining a data address of the adapter using at least one of information in the function table entry and the offset; and fetching data from a specific location in the address space identified by the designation of the address space, the specific location identified by the data address of the adapter.