File:  [gforth] / gforth / kernel / vars.fs
Revision 1.10: download - view: text, annotated - select for diffs
Wed Feb 3 00:10:26 1999 UTC (22 years, 5 months ago) by crook
Branches: MAIN
CVS tags: HEAD
New "docclean" target for makefile (removes glossary dependencies when
rebuilding documentation). Changes to .fs files and prim are restricted
to glossary (\G) additions for the documentation; this has necessitated
the addition of new white-space in places to stop the \G stuff from
obscuring the code. Many additions to doc/gforth.ds - new sections
added, a few things moved and some sections re-written slightly. There
are a set of things to tidy up before this rev. is suitable for
release, and those will be my highest priority. I have also used
"@comment TODO" to highlight other sections I plan to work on, and
added a set of comments at the start to indicate other things I plan
to modify in the medium-term.

    1: \ VARS.FS      Kernal variables
    2: 
    3: \ Copyright (C) 1995,1996,1997,1998 Free Software Foundation, Inc.
    4: 
    5: \ This file is part of Gforth.
    6: 
    7: \ Gforth is free software; you can redistribute it and/or
    8: \ modify it under the terms of the GNU General Public License
    9: \ as published by the Free Software Foundation; either version 2
   10: \ of the License, or (at your option) any later version.
   11: 
   12: \ This program is distributed in the hope that it will be useful,
   13: \ but WITHOUT ANY WARRANTY; without even the implied warranty of
   14: \ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   15: \ GNU General Public License for more details.
   16: 
   17: \ You should have received a copy of the GNU General Public License
   18: \ along with this program; if not, write to the Free Software
   19: \ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   20: 
   21: hex \ everything now hex!                               11may93jaw
   22: 
   23: \ important constants                                  17dec92py
   24: 
   25: \ dpANS6 (sect 3.1.3.1) says 
   26: \ "a true flag ... [is] a single-cell value with all bits set"
   27: \ better definition: 0 0= constant true ( no dependence on 2's compl)
   28:  -1 Constant true ( -- f ) \ core-ext
   29: \G CONSTANT: f is a cell with all bits set.
   30: \ see starts looking for primitives after this word!
   31: 
   32:   0 Constant false ( -- f ) \ core-ext
   33: \G CONSTANT: f is a cell with all bits clear.
   34: 
   35: 1 cells Constant cell ( -- u ) \ gforth
   36: 1 floats Constant float ( -- u ) \ gforth
   37: 
   38: 20 Constant bl ( -- c-char ) \ core
   39: \G c-char is the character value for a space.
   40: \ used by docon:, must be constant
   41: 
   42: FF Constant /line
   43: 
   44: 40 Constant c/l
   45: 10 Constant l/s
   46: 400 Constant chars/block
   47: 
   48: $20 8 2* cells + 2 + cell+ constant word-pno-size ( -- u )
   49: 84 constant pad-minsize ( -- u )
   50: 
   51: \ that's enough so long
   52: 
   53: \ User variables                                       13feb93py
   54: 
   55: \ initialized by COLD
   56: 
   57: Create main-task  has? OS [IF] 100 [ELSE] 40 [THEN] cells allot
   58: 
   59: \ set user-pointer from cross-compiler right
   60: main-task 
   61: UNLOCK tup ! LOCK
   62: 
   63: Variable udp \ user area size? -anton
   64: 
   65: AUser next-task        main-task next-task !
   66: AUser prev-task        main-task prev-task !
   67: AUser save-task        0 save-task !
   68: AUser sp0 ( -- a-addr ) \ gforth
   69: \G USER VARIABLE: Initial value of the data stack pointer.
   70: \ sp0 is used by douser:, must be user
   71:     ' sp0 Alias s0 ( -- a-addr ) \ gforth
   72: \G OBSOLETE alias of @code{sp0}
   73: 
   74: AUser rp0 ( -- a-addr ) \ gforth
   75: \G USER VARIABLE: Initial value of the return stack pointer.
   76:     ' rp0 Alias r0 ( -- a-addr ) \ gforth
   77: \G OBSOLETE alias of @code{rp0}
   78: 
   79: AUser fp0 ( -- a-addr ) \ gforth
   80: \G USER VARIABLE: Initial value of the floating-point stack pointer.
   81: \ no f0, because this leads to unexpected results when using hex
   82: 
   83: AUser lp0 ( -- a-addr ) \ gforth
   84: \G USER VARIABLE: Initial value of the locals stack pointer.
   85:     ' lp0 Alias l0 ( -- a-addr ) \ gforth
   86: \G OBSOLETE alias of @code{lp0}
   87: 
   88: AUser handler	\ pointer to last throw frame
   89: AUser backtrace-empty \ true if the next THROW should store a backtrace
   90: \ AUser output
   91: \ AUser input
   92: 
   93: AUser errorhandler
   94: 
   95: AUser "error            0 "error !
   96: 
   97: [IFUNDEF] #tib		\ in ec-Version we may define this ourself
   98:  User tibstack		\ saves >tib in execute
   99:  User >tib		\ pointer to terminal input buffer
  100:  User #tib ( -- a-addr ) \ core-ext
  101:  \G USER VARIABLE: a-addr is the address of a cell containing
  102:  \G the number of characters in the terminal input buffer.
  103:  \G OBSOLESCENT: @code{source} superceeds the function of this word.
  104: 
  105:  User >in ( -- a-addr ) \ core
  106:  \G USER VARIABLE: a-addr is the address of a cell containing the
  107:  \G char offset from the start of the terminal input buffer to the
  108:  \G start of the parse area
  109:                         0 >in ! \ char number currently processed in tib
  110: [THEN]
  111: has? file [IF]
  112:  User blk ( -- a-addr ) \ block
  113:  \G USER VARIABLE: a-addr is the address of a cell containing zero
  114:  \G (in which case the input source is not a block and can be identified
  115:  \G by @code{source-id}) or the number of the block currently being
  116:  \G interpreted. A Standard program should not alter @code{blk} directly.
  117: 			0 blk !
  118: 
  119:  User loadfile          0 loadfile !
  120: 
  121:  User loadfilename#	0 loadfilename# !
  122: 
  123:  User loadline          \ number of the currently interpreted
  124:                         \ (in TIB) line if the interpretation
  125:                         \ is in a textfile
  126:                         \ the first line is 1
  127: 
  128: 2User linestart         \ starting file postition of
  129:                         \ the current interpreted line (in TIB)
  130: [THEN]
  131: 
  132:  User base ( -- a-addr ) \ core
  133:  \G USER VARIABLE: a-addr is the address of a cell that stores the
  134:  \G number base used by default for number conversion during input and output.
  135:                         A base !
  136:  User dpl               -1 dpl !
  137: 
  138:  User state ( -- a-addr ) \ core,tools-ext
  139:  \G USER VARIABLE: a-addr is the address of a cell containing
  140:  \G the compilation state flag. 0 => interpreting, -1 => compiling.
  141:  \G A program shall not directly alter the value of @code{state}. The
  142:  \G following Standard words alter the value in @code{state}:
  143:  \G @code{:} (colon) @code{;} (semicolon) @code{abort} @code{quit}
  144:  \G @code{:noname} @code{[} (left-bracket) @code{]} (right-bracket)
  145:  \G @code{;code}
  146: 			0 state !
  147: 
  148: AUser normal-dp		\ the usual dictionary pointer
  149: AUser dpp		normal-dp dpp !
  150: 			\ the pointer to the current dictionary pointer
  151:                         \ ist reset to normal-dp on (doerror)
  152:                         \  (i.e. any throw caught by quit)
  153: AUser LastCFA
  154: AUser Last
  155: 
  156: has? glocals [IF]
  157: User locals-size \ this is the current size of the locals stack
  158: 		 \ frame of the current word
  159: [THEN]
  160: 

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