1. In a system having a data path functional unit having a functional unit data path width, a first memory system having a first data path width, and a second memory system having a data path width which is greater than the functional unit data path width and greater than the first data path width, a method comprising: copying a first memory operand portion from the first memory system to the second memory system, the first memory operand portion having the first data path width; and copying a second memory operand portion from the first memory system to the second memory system, the second memory operand portion having the first data path width and being catenated in the second memory system with the first memory operand portion, thereby forming catenated data.