1: \ VARS.FS Kernal variables
2:
3: \ Copyright (C) 1995,1996,1997,1998,2000 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., 59 Temple Place, Suite 330, Boston, MA 02111, 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 @code{Constant} -- @i{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 @code{Constant} -- @i{f} is a cell with all bits clear.
34:
35: [IFUNDEF] cell
36: 1 cells Constant cell ( -- u ) \ gforth
37: \G @code{Constant} -- @code{1 cells}
38: [THEN]
39:
40: 1 floats Constant float ( -- u ) \ gforth
41: \G @code{Constant} -- the number of address units corresponding to a floating-point number.
42:
43: 20 Constant bl ( -- c-char ) \ core b-l
44: \G @i{c-char} is the character value for a space.
45: \ used by docon:, must be constant
46:
47: FF Constant /line
48:
49: 40 Constant c/l
50: 10 Constant l/s
51: 400 Constant chars/block
52:
53: 20 8 2* cells + 2 + cell+ constant word-pno-size ( -- u )
54: create holdbuf word-pno-size chars allot
55: holdbuf word-pno-size chars + aconstant holdbuf-end
56: avariable holdptr holdbuf-end holdptr a!
57: avariable holdend holdbuf-end holdend a!
58:
59: 84 constant pad-minsize ( -- u )
60:
61:
62: \ that's enough so long
63:
64: \ User variables 13feb93py
65:
66: \ initialized by COLD
67:
68: Create main-task has? OS [IF] 100 [ELSE] 40 [THEN] cells allot
69:
70: \ set user-pointer from cross-compiler right
71: main-task
72: UNLOCK tup ! LOCK
73:
74: Variable udp ( -- a-addr ) \ gforth
75: \ user area size? -anton
76:
77: AUser next-task main-task next-task !
78: AUser prev-task main-task prev-task !
79: AUser save-task 0 save-task !
80: AUser sp0 ( -- a-addr ) \ gforth
81: \G @code{User} variable -- initial value of the data stack pointer.
82: \ sp0 is used by douser:, must be user
83: ' sp0 Alias s0 ( -- a-addr ) \ gforth
84: \G OBSOLETE alias of @code{sp0}
85:
86: AUser rp0 ( -- a-addr ) \ gforth
87: \G @code{User} variable -- initial value of the return stack pointer.
88: ' rp0 Alias r0 ( -- a-addr ) \ gforth
89: \G OBSOLETE alias of @code{rp0}
90:
91: AUser fp0 ( -- a-addr ) \ gforth
92: \G @code{User} variable -- initial value of the floating-point stack pointer.
93: \ no f0, because this leads to unexpected results when using hex
94:
95: AUser lp0 ( -- a-addr ) \ gforth
96: \G @code{User} variable -- initial value of the locals stack pointer.
97: ' lp0 Alias l0 ( -- a-addr ) \ gforth
98: \G OBSOLETE alias of @code{lp0}
99:
100: AUser handler \ pointer to last throw frame
101: has? backtrace [IF]
102: User backtrace-empty \ true if the next THROW should store a backtrace
103: AUser backtrace-rp0 \ rp at last call of interpret
104: [THEN]
105: \ AUser output
106: \ AUser input
107:
108: AUser errorhandler
109:
110: AUser "error 0 "error !
111:
112: [IFUNDEF] #tib \ in ec-Version we may define this ourself
113: User tibstack \ saves >tib in execute
114: User >tib \ pointer to terminal input buffer
115: User #tib ( -- a-addr ) \ core-ext number-t-i-b
116: \G @code{User} variable -- @i{a-addr} is the address of a cell containing
117: \G the number of characters in the terminal input buffer.
118: \G OBSOLESCENT: @code{source} superceeds the function of this word.
119:
120: User >in ( -- a-addr ) \ core to-in
121: \G @code{User} variable -- @i{a-addr} is the address of a cell containing the
122: \G char offset from the start of the input buffer to the start of the
123: \G parse area.
124: 0 >in ! \ char number currently processed in tib
125: [THEN]
126: has? file [IF]
127: User blk ( -- a-addr ) \ block b-l-k
128: \G @code{User} variable -- @i{a-addr} is the address of a cell containing zero
129: \G (in which case the input source is not a block and can be identified
130: \G by @code{source-id}) or the number of the block currently being
131: \G interpreted. A Standard program should not alter @code{blk} directly.
132: 0 blk !
133:
134: User loadfile 0 loadfile !
135:
136: User loadfilename# 0 loadfilename# !
137:
138: User loadline \ number of the currently interpreted
139: \ (in TIB) line if the interpretation
140: \ is in a textfile
141: \ the first line is 1
142:
143: 2User linestart \ starting file postition of
144: \ the current interpreted line (in TIB)
145: [THEN]
146:
147: User base ( -- a-addr ) \ core
148: \G @code{User} variable -- @i{a-addr} is the address of a cell that stores the
149: \G number base used by default for number conversion during input and output.
150: A base !
151: User dpl ( -- a-addr ) \ gforth
152: \G @code{User} variable -- @i{a-addr} is the address of a cell that stores the
153: \G position of the decimal point in the most recent numeric conversion.
154: \G Initialised to -1. After the conversion of a number containing no
155: \G decimal point, @code{@ dpl} is -1. After the conversion of @code{2.} it holds
156: \G 0. After the conversion of 234123.9 it contains 1, and so forth.
157: -1 dpl !
158:
159: User state ( -- a-addr ) \ core,tools-ext
160: \G @code{User} variable -- @i{a-addr} is the address of a cell
161: \G containing the compilation state flag. 0 => interpreting, -1 =>
162: \G compiling. A program shall not directly alter the value of
163: \G @code{state}. The following Standard words alter the value in
164: \G @code{state}: @code{:} (colon) @code{;} (semicolon) @code{abort}
165: \G @code{quit} @code{:noname} @code{[} (left-bracket) @code{]}
166: \G (right-bracket) @code{;code}. Don't use @code{state}! For an
167: \G alternative see @ref{Interpretation and Compilation Semantics}.
168: \ Recommended reading: @cite{@code{State}-smartness--Why it is evil
169: \ and how to exorcise it},
170: \ @url{http://www.complang.tuwien.ac.at/papers/ertl98.ps.gz}; short
171: \ version: Don't use @code{state}!
172: 0 state !
173:
174: AUser normal-dp \ the usual dictionary pointer
175: AUser dpp normal-dp dpp !
176: \ the pointer to the current dictionary pointer
177: \ ist reset to normal-dp on (doerror)
178: \ (i.e. any throw caught by quit)
179: AUser LastCFA
180: AUser Last
181:
182: has? glocals [IF]
183: User locals-size \ this is the current size of the locals stack
184: \ frame of the current word
185: [THEN]
186:
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