The UPT (UPdate Tree) instruction inserts a new node in a tree conditionally. If it does not find an existing node having a nominated key in a [sub]tree, it inserts a new node into that [sub]tree at a location that, while not inappropriate, can be suboptimal.
It is thus useful for maintaining a dynamic tree, e.g., a compiler's 'symbol table', but not for many of the validating uses---Is this search argument a supported keyword? and the like---of search operations. It also has the severe limitation that even in AMODE(64) a node---both key AND chaining information---is only a quadword in size. I have not found it very useful, but further experimentation is certainly in order. It is or, perhaps better, would be fast. John Gilmore, Ashland, MA 01721 - USA ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
