Running smaller memory-address width program code in a larger memory-address width address space

Method and system are provided for running a smaller memory-address width program in a larger memory-address width address space. The method includes: dividing a smaller memory-address width program executable code into a set of portions; reserving a first virtual storage area in a part of an address space accessed using a smaller memory-address width address; and reserving a set of second virtual storage areas in a part of the address space accessed using a larger memory-address width address to accommodate the program executable code. The method provides a relocation mechanism to relocate a processor thread by translating using a relocation factor from an address in the reserved first virtual storage area to the one of the reserved second virtual storage areas containing the executable code.