\ VARS.FS Kernal variables \ Copyright (C) 1995,1996,1997,1998 Free Software Foundation, Inc. \ This file is part of Gforth. \ Gforth is free software; you can redistribute it and/or \ modify it under the terms of the GNU General Public License \ as published by the Free Software Foundation; either version 2 \ of the License, or (at your option) any later version. \ This program is distributed in the hope that it will be useful, \ but WITHOUT ANY WARRANTY; without even the implied warranty of \ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the \ GNU General Public License for more details. \ You should have received a copy of the GNU General Public License \ along with this program; if not, write to the Free Software \ Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. hex \ everything now hex! 11may93jaw \ important constants 17dec92py \ dpANS6 (sect 3.1.3.1) says \ "a true flag ... [is] a single-cell value with all bits set" \ better definition: 0 0= constant true ( no dependence on 2's compl) -1 Constant true ( -- f ) \ core-ext \G @code{Constant} -- @i{f} is a cell with all bits set. \ see starts looking for primitives after this word! 0 Constant false ( -- f ) \ core-ext \G @code{Constant} -- @i{f} is a cell with all bits clear. [IFUNDEF] cell 1 cells Constant cell ( -- u ) \ gforth \G @code{Constant} -- @code{1 cells} [THEN] 1 floats Constant float ( -- u ) \ gforth \G @code{Constant} -- the number of address units corresponding to a floating-point number. 20 Constant bl ( -- c-char ) \ core b-l \G @i{c-char} is the character value for a space. \ used by docon:, must be constant FF Constant /line 40 Constant c/l 10 Constant l/s 400 Constant chars/block 20 8 2* cells + 2 + cell+ constant word-pno-size ( -- u ) create holdbuf word-pno-size chars allot holdbuf word-pno-size chars + aconstant holdbuf-end avariable holdptr holdbuf-end holdptr a! avariable holdend holdbuf-end holdend a! 84 constant pad-minsize ( -- u ) \ that's enough so long \ User variables 13feb93py \ initialized by COLD Create main-task has? OS [IF] 100 [ELSE] 40 [THEN] cells allot \ set user-pointer from cross-compiler right main-task UNLOCK tup ! LOCK Variable udp ( -- a-addr ) \ gforth \ user area size? -anton AUser next-task main-task next-task ! AUser prev-task main-task prev-task ! AUser save-task 0 save-task ! AUser sp0 ( -- a-addr ) \ gforth \G @code{User} variable -- initial value of the data stack pointer. \ sp0 is used by douser:, must be user ' sp0 Alias s0 ( -- a-addr ) \ gforth \G OBSOLETE alias of @code{sp0} AUser rp0 ( -- a-addr ) \ gforth \G @code{User} variable -- initial value of the return stack pointer. ' rp0 Alias r0 ( -- a-addr ) \ gforth \G OBSOLETE alias of @code{rp0} AUser fp0 ( -- a-addr ) \ gforth \G @code{User} variable -- initial value of the floating-point stack pointer. \ no f0, because this leads to unexpected results when using hex AUser lp0 ( -- a-addr ) \ gforth \G @code{User} variable -- initial value of the locals stack pointer. ' lp0 Alias l0 ( -- a-addr ) \ gforth \G OBSOLETE alias of @code{lp0} AUser handler \ pointer to last throw frame has? backtrace [IF] User backtrace-empty \ true if the next THROW should store a backtrace AUser backtrace-rp0 \ rp at last call of interpret [THEN] \ AUser output \ AUser input AUser errorhandler AUser "error 0 "error ! [IFUNDEF] #tib \ in ec-Version we may define this ourself User tibstack \ saves >tib in execute User >tib \ pointer to terminal input buffer User #tib ( -- a-addr ) \ core-ext number-t-i-b \G @code{User} variable -- @i{a-addr} is the address of a cell containing \G the number of characters in the terminal input buffer. \G OBSOLESCENT: @code{source} superceeds the function of this word. User >in ( -- a-addr ) \ core to-in \G @code{User} variable -- @i{a-addr} is the address of a cell containing the \G char offset from the start of the input buffer to the start of the \G parse area. 0 >in ! \ char number currently processed in tib [THEN] has? file [IF] User blk ( -- a-addr ) \ block b-l-k \G @code{User} variable -- @i{a-addr} is the address of a cell containing zero \G (in which case the input source is not a block and can be identified \G by @code{source-id}) or the number of the block currently being \G interpreted. A Standard program should not alter @code{blk} directly. 0 blk ! User loadfile 0 loadfile ! User loadfilename# 0 loadfilename# ! User loadline \ number of the currently interpreted \ (in TIB) line if the interpretation \ is in a textfile \ the first line is 1 2User linestart \ starting file postition of \ the current interpreted line (in TIB) [THEN] User base ( -- a-addr ) \ core \G @code{User} variable -- @i{a-addr} is the address of a cell that stores the \G number base used by default for number conversion during input and output. A base ! User dpl ( -- a-addr ) \ gforth \G @code{User} variable -- @i{a-addr} is the address of a cell that stores the \G position of the decimal point in the most recent numeric conversion. \G Initialised to -1. After the conversion of a number containing no \G decimal point, @code{@ dpl} is -1. After the conversion of @code{2.} it holds \G 0. After the conversion of 234123.9 it contains 1, and so forth. -1 dpl ! User state ( -- a-addr ) \ core,tools-ext \G @code{User} variable -- @i{a-addr} is the address of a cell \G containing the compilation state flag. 0 => interpreting, -1 => \G compiling. A program shall not directly alter the value of \G @code{state}. The following Standard words alter the value in \G @code{state}: @code{:} (colon) @code{;} (semicolon) @code{abort} \G @code{quit} @code{:noname} @code{[} (left-bracket) @code{]} \G (right-bracket) @code{;code}. Don't use @code{state}! For an \G alternative see @ref{Interpretation and Compilation Semantics}. \ Recommended reading: @cite{@code{State}-smartness--Why it is evil \ and how to exorcise it}, \ @url{http://www.complang.tuwien.ac.at/papers/ertl98.ps.gz}; short \ version: Don't use @code{state}! 0 state ! AUser normal-dp \ the usual dictionary pointer AUser dpp normal-dp dpp ! \ the pointer to the current dictionary pointer \ ist reset to normal-dp on (doerror) \ (i.e. any throw caught by quit) AUser LastCFA AUser Last has? glocals [IF] User locals-size \ this is the current size of the locals stack \ frame of the current word [THEN]