File:  [gforth] / gforth / kernel / vars.fs
Revision 1.12: download - view: text, annotated - select for diffs
Mon Feb 22 21:39:44 1999 UTC (22 years, 7 months ago) by anton
Branches: MAIN
CVS tags: HEAD
renamed nalign into naligned (nalign is present but obsolete)
Implemented a new solution for nested hold areas (<<# ... #> ... #>>)
minor changes

    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: create holdbuf word-pno-size chars allot
   50: holdbuf word-pno-size chars + aconstant holdbuf-end
   51: avariable holdptr holdbuf-end holdptr a!
   52: avariable holdend holdbuf-end holdend a!
   53: 
   54: 84 constant pad-minsize ( -- u )
   55: 
   56: 
   57: \ that's enough so long
   58: 
   59: \ User variables                                       13feb93py
   60: 
   61: \ initialized by COLD
   62: 
   63: Create main-task  has? OS [IF] 100 [ELSE] 40 [THEN] cells allot
   64: 
   65: \ set user-pointer from cross-compiler right
   66: main-task 
   67: UNLOCK tup ! LOCK
   68: 
   69: Variable udp \ user area size? -anton
   70: 
   71: AUser next-task        main-task next-task !
   72: AUser prev-task        main-task prev-task !
   73: AUser save-task        0 save-task !
   74: AUser sp0 ( -- a-addr ) \ gforth
   75: \G USER VARIABLE: Initial value of the data stack pointer.
   76: \ sp0 is used by douser:, must be user
   77:     ' sp0 Alias s0 ( -- a-addr ) \ gforth
   78: \G OBSOLETE alias of @code{sp0}
   79: 
   80: AUser rp0 ( -- a-addr ) \ gforth
   81: \G USER VARIABLE: Initial value of the return stack pointer.
   82:     ' rp0 Alias r0 ( -- a-addr ) \ gforth
   83: \G OBSOLETE alias of @code{rp0}
   84: 
   85: AUser fp0 ( -- a-addr ) \ gforth
   86: \G USER VARIABLE: Initial value of the floating-point stack pointer.
   87: \ no f0, because this leads to unexpected results when using hex
   88: 
   89: AUser lp0 ( -- a-addr ) \ gforth
   90: \G USER VARIABLE: Initial value of the locals stack pointer.
   91:     ' lp0 Alias l0 ( -- a-addr ) \ gforth
   92: \G OBSOLETE alias of @code{lp0}
   93: 
   94: AUser handler	\ pointer to last throw frame
   95: AUser backtrace-empty \ true if the next THROW should store a backtrace
   96: \ AUser output
   97: \ AUser input
   98: 
   99: AUser errorhandler
  100: 
  101: AUser "error            0 "error !
  102: 
  103: [IFUNDEF] #tib		\ in ec-Version we may define this ourself
  104:  User tibstack		\ saves >tib in execute
  105:  User >tib		\ pointer to terminal input buffer
  106:  User #tib ( -- a-addr ) \ core-ext
  107:  \G USER VARIABLE: a-addr is the address of a cell containing
  108:  \G the number of characters in the terminal input buffer.
  109:  \G OBSOLESCENT: @code{source} superceeds the function of this word.
  110: 
  111:  User >in ( -- a-addr ) \ core
  112:  \G USER VARIABLE: a-addr is the address of a cell containing the
  113:  \G char offset from the start of the terminal input buffer to the
  114:  \G start of the parse area
  115:                         0 >in ! \ char number currently processed in tib
  116: [THEN]
  117: has? file [IF]
  118:  User blk ( -- a-addr ) \ block
  119:  \G USER VARIABLE: a-addr is the address of a cell containing zero
  120:  \G (in which case the input source is not a block and can be identified
  121:  \G by @code{source-id}) or the number of the block currently being
  122:  \G interpreted. A Standard program should not alter @code{blk} directly.
  123: 			0 blk !
  124: 
  125:  User loadfile          0 loadfile !
  126: 
  127:  User loadfilename#	0 loadfilename# !
  128: 
  129:  User loadline          \ number of the currently interpreted
  130:                         \ (in TIB) line if the interpretation
  131:                         \ is in a textfile
  132:                         \ the first line is 1
  133: 
  134: 2User linestart         \ starting file postition of
  135:                         \ the current interpreted line (in TIB)
  136: [THEN]
  137: 
  138:  User base ( -- a-addr ) \ core
  139:  \G USER VARIABLE: a-addr is the address of a cell that stores the
  140:  \G number base used by default for number conversion during input and output.
  141:                         A base !
  142:  User dpl               -1 dpl !
  143: 
  144:  User state ( -- a-addr ) \ core,tools-ext
  145:  \G Recommended reading: @cite{@code{State}-smartness--Why it is evil
  146:  \G and how to exorcise it},
  147:  \G @url{http://www.complang.tuwien.ac.at/papers/ertl98.ps.gz}; short
  148:  \G version: Don't use @code{state}! @xref{Interpretation and
  149:  \G Compilation Semantics} for an alternative. USER VARIABLE: a-addr
  150:  \G is the address of a cell containing the compilation state flag. 0
  151:  \G => interpreting, -1 => compiling.  A program shall not directly
  152:  \G alter the value of @code{state}. The following Standard words
  153:  \G alter the value in @code{state}: @code{:} (colon) @code{;}
  154:  \G (semicolon) @code{abort} @code{quit} @code{:noname} @code{[}
  155:  \G (left-bracket) @code{]} (right-bracket) @code{;code}
  156: 			0 state !
  157: 
  158: AUser normal-dp		\ the usual dictionary pointer
  159: AUser dpp		normal-dp dpp !
  160: 			\ the pointer to the current dictionary pointer
  161:                         \ ist reset to normal-dp on (doerror)
  162:                         \  (i.e. any throw caught by quit)
  163: AUser LastCFA
  164: AUser Last
  165: 
  166: has? glocals [IF]
  167: User locals-size \ this is the current size of the locals stack
  168: 		 \ frame of the current word
  169: [THEN]
  170: 

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