In a data processing system in which the execution unit is implemented to process aligned double word operands, apparatus and an associated method provide for the alignment of a double word operand that is stored across a double word boundary. The two double words each storing a word of the unaligned double word operand are identified and the attributes are compared with the ring number of the associated program. When the comparisons indicate that the two words of the non-aligned double word operand are available to the program, the two double word operands containing non-aligned words of the double word operand, and the two non-aligned words are stored in a register in an aligned orientation for processing by the execution unit.