When an arithmetic value has the same data attributes (except for precision) as the target, precision conversion is required.
For fixed-point data items, decimal or binary point alignment is maintained during precision conversion. Therefore, padding or truncation can occur on the left or right. If nonzero bits or digits on the left are lost, the SIZE condition is raised.
For floating-point data items, truncation on the right, or padding on the right with zeros, can occur.