Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 exptools 1/6/84; site iham1.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxj!ihnp4!iham1!gjphw From: gjphw@iham1.UUCP Newsgroups: net.lang.forth,net.micro.ti Subject: FORTH returns on a TI 99/4A Message-ID: <233@iham1.UUCP> Date: Wed, 10-Oct-84 19:23:27 EDT Article-I.D.: iham1.233 Posted: Wed Oct 10 19:23:27 1984 Date-Received: Fri, 12-Oct-84 08:04:01 EDT Organization: AT&T Bell Labs, Naperville, IL Lines: 35 An article appeared in a recent issue of BYTE presenting a case for changing the way FORTH handles its threading. Ordinarily, FORTH's resident words are written in assembler and the user defined words are threaded using these resident words and other user defined words. At the end of any particular word, a return pointer to the preceding word is stored. The article said that this technique was used to keep FORTH small. A faster way to handle returns from any particular word would be to use the return procedure built into the microprocessor. Rather than going through the bother of storing the pointers, the author argued that treating every word as a subroutine would provide faster execution. He then gave some comparisons between the usual pointer returns and the subroutine/macro routines that he advocated. I have the opportunity to obtain the assembly source code for the FORTH that has been implemented by Texas Instruments on their TI 99/4A. If there is indeed a significant performance improvement to be realized, a nice project for me might involve modifying the returns according to this guy's proposal. My question concerns the value of the article's argument. Is there a significant performance improvement to be had by treating FORTH words as subroutines? Has anyone in netland considered this possibility? Are there presently some implementations of FORTH that already treat its words as subroutines (and uses the subroutine return native to the micro)? Replies will be read if either posted to this newsgroup or sent to me directly. Thank you. -- Patrick Wyant AT&T Bell Laboratories (Naperville, IL) *!iham1!gjphw