At 02:51 +0000 on 10/08/2010, john gilmore wrote about Re: 16 bytes the same:
Apart from its obvious usefulness in processing right-to-left text like that of Arabic, Farsi, and Hebrew, the TRTR instruction is valuable for locating the rightmost non-blank character in left-to-right text.
TRT'ing the string in a workarea after doing a MVCI of the original into a workarea is the way I used to do this before TRTR. Before MVCI, a TR into a workarea filled from a constant of A DC 256AL1(*-A+255) which creates FFFE...0100 and using the original as the TRT Table (you use the last original x=length of field to be scanned bytes of the A string to fill the work area). The introduction of MVCI made the need to use a TR as a patterned move instruction (although it is still useful for things like reversing the order of a sequence of Full Words/etc.).
