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Re: STATE

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"MarkWills" <markrobertwills@yahoo.co.uk> wrote in message
news:d78fa1a4-efa0-435f-8d3a-d97cc3a439fd@24g2000yqk.googlegroups.com...
>
> I guess I should have said VALUE rather than
> VARIABLE. The point being, STATE would return its value, rather than
> its address, since there is rarely (if ever) a need to directly write
> to STATE, especially in a user program. I accept its largely a moot
> point; clearly there are thousands of lines of legacy code that would
> break if it were to be changed now.
>

I don't know if it's moot.  E.g., the version of the fig-Forth spec. that's
available as text, says TIB returns an address:

"
      TIB           ---  addr                               U
               A user variable containing the address of the terminal
               input buffer.
"

DP is stated to be implemented the same way as TIB.  The fig-Forth memory
map shows the same thing.  I.e., both should be variables that place the
address on the stack:

"
      DP            ---  addr                               U,L
               A user variable, the dictionary pointer, which contains
               the address of the next free memory above the dictionary.
               The value may be read by HERE and altered by ALLOT.
"

When working on my interpreter, I implemented TIB that needed to be fetched,
just like DP.  However, much example code using TIB just didn't work!  So, I
checked some Forths on their use of TIB and DP.  Many didn't have, or don't
allow, access to TIB or DP.  When present, TIB is not fetched.  The one
exception being 8088 fig-Forth.  When present, DP is fetched.  So, I'm only
aware of one Forth interpreter that follows the fig-Forth spec. in regards
to TIB being a variable.  I.e., almost no Forths, that use TIB, correctly
implement TIB as a variable.  Yes?  They both should work the same way, and
user variable's return the variable's address, not the variable's content
which are addresses in this case.  Correct?

I tried both of these sequences to see if TIB is fetched:

TIB @ 5 TYPE
TIB 5 TYPE

I used this sequence to determine if DP is fetched:

HERE . 1 ALLOT HERE . DP . DP @ .

BTW, I saw someone say in post here that TIB needed to be 80 per user.  If
you follow the fig-Forth spec., it's 82, for EOL...


Rod Pemberton

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STATE MarkWills <markrobertwills@yahoo.co.uk> - 2011-04-27 12:41 -0700
  Re: STATE Alex McDonald <blog@rivadpm.com> - 2011-04-27 13:04 -0700
    Re: STATE MarkWills <markrobertwills@yahoo.co.uk> - 2011-04-27 13:13 -0700
      Re: STATE Alex McDonald <blog@rivadpm.com> - 2011-04-27 13:45 -0700
    Re: STATE "P.M.Lawrence" <pml540114@gmail.com> - 2011-04-28 03:00 -0700
      Re: STATE Alex McDonald <blog@rivadpm.com> - 2011-04-28 04:09 -0700
        Re: STATE Alex McDonald <blog@rivadpm.com> - 2011-04-28 04:10 -0700
  Re: STATE Micke <oh2aun@gmail.com> - 2011-04-27 13:20 -0700
    Re: STATE MarkWills <markrobertwills@yahoo.co.uk> - 2011-04-27 13:26 -0700
      Re: STATE MarkWills <markrobertwills@yahoo.co.uk> - 2011-04-27 13:30 -0700
      Re: STATE Elizabeth D Rather <erather@forth.com> - 2011-04-27 11:13 -1000
        Re: STATE Elizabeth D Rather <erather@forth.com> - 2011-04-27 17:17 -1000
        Re: STATE Andrew Haley <andrew29@littlepinkcloud.invalid> - 2011-04-29 06:14 -0500
          Re: STATE Elizabeth D Rather <erather@forth.com> - 2011-04-29 08:47 -1000
            Re: STATE MarkWills <markrobertwills@yahoo.co.uk> - 2011-04-29 14:07 -0700
  Re: STATE BruceMcF <agila61@netscape.net> - 2011-04-27 19:22 -0700
  Re: STATE BruceMcF <agila61@netscape.net> - 2011-04-30 08:18 -0700
  Re: STATE BruceMcF <agila61@netscape.net> - 2011-04-30 08:26 -0700
  Re: STATE "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2011-04-30 03:24 -0400
  Re: STATE stephenXXX@mpeforth.com (Stephen Pelc) - 2011-04-30 11:41 +0000
  Re: STATE stephenXXX@mpeforth.com (Stephen Pelc) - 2011-04-30 11:53 +0000
    Re: STATE BruceMcF <agila61@netscape.net> - 2011-04-30 08:48 -0700
  Re: STATE anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2011-04-28 08:59 +0000
    Re: STATE Brad <hwfwguy@gmail.com> - 2011-04-28 08:01 -0700
      Re: STATE Andrew Haley <andrew29@littlepinkcloud.invalid> - 2011-04-28 12:16 -0500
        Re: STATE Elizabeth D Rather <erather@forth.com> - 2011-04-28 09:47 -1000
      Re: STATE BruceMcF <agila61@netscape.net> - 2011-04-28 15:56 -0700
        Re: STATE Brad <hwfwguy@gmail.com> - 2011-04-29 07:49 -0700
          Re: STATE BruceMcF <agila61@netscape.net> - 2011-04-29 11:47 -0700
      Re: STATE anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2011-04-29 17:30 +0000
    Re: STATE Albert van der Horst <albert@spenarnc.xs4all.nl> - 2011-04-28 17:47 +0000
      Re: STATE Elizabeth D Rather <erather@forth.com> - 2011-04-28 09:50 -1000
  Re: STATE "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2011-04-28 16:32 -0400
    Re: STATE MarkWills <markrobertwills@yahoo.co.uk> - 2011-04-29 02:11 -0700
      Re: STATE BruceMcF <agila61@netscape.net> - 2011-04-29 07:24 -0700
      Re: STATE "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2011-04-29 13:56 -0400
        Re: STATE BruceMcF <agila61@netscape.net> - 2011-04-29 11:44 -0700
          Re: STATE "Rod Pemberton" <do_not_have@noavailemail.cmm> - 2011-04-29 15:45 -0400
            Re: STATE Elizabeth D Rather <erather@forth.com> - 2011-04-29 10:22 -1000
            Re: STATE BruceMcF <agila61@netscape.net> - 2011-04-29 13:31 -0700
        Re: STATE Elizabeth D Rather <erather@forth.com> - 2011-04-29 09:07 -1000

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