Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!ucbvax!UICVMC.BITNET!UWC6NTG
From: UWC6NTG@UICVMC.BITNET (Nicholas Geovanis 312-996-0590)
Newsgroups: comp.lang.forth
Subject: (none)
Message-ID: <8906261431.AA14584@jade.berkeley.edu>
Date: 25 Jun 89 14:57:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: Forth Interest Group International List <FIGI-L%SCFVM.bitnet@jade.berkeley.edu>
Organization: The Internet
Lines: 29

>
>o  Does a 32-bit FORTH imply that a 16-bit data type is not
>   available?
>o  How are 16-bit loads & stores implemented?
>   (perhaps S! and S@ ?!)
>o  How are character strings stored in memory?
>   (4 characters per word, or 1 character and 3 chars free)
>o  Is there any standard for 32-bit FORTHS out there?

   I wrote a 32-bit FORTH interpreter for VM/CMS as an independent study
project a couple years back. My answers to these questions were:
   1) Although S/370 architecture has a full set of arithmetic operators
      for halfwords (16-bit words), in my experience they aren't really
      used very often. I saw no reason to implement FORTH primitives for them.
      Incidentally, I wrote the fetch and store words such that fullword
      alignment was unnecessary for arithmetic. The stack was so aligned.
   2) There were none, as above. One could use the standard FORTH string
      operators if one simply wants to plunk down a couple bytes.
   3) I stored my characters four per word. The historical/architectural
      rationale for "one-character-per-word" does not apply in the S/370
      world, and probably not in, say, the 68000 world.
   4) I did my best to adhere to the FORTH-79 standard (OK, I hear the
      cheers. FORTH-83 wasn't as well accepted then as it is now),
      simply ignoring the so-called two-byte arithmetic operators. If you
      ignore the fact that the 8-bit word and the 64K addressability are
      written into the '79 standard, the words themselves are pretty
      implementation-independent. Just make the stack, arithmetic words,
      etc., work with 32-bit words.
                              NickGeovanis - UWC6NTG@UICVMC