1: \ VARS.FS Kernal variables
2:
3: \ Copyright (C) 1995,1996,1997,1998,2000,2003 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: has? floating [IF]
41: 1 floats Constant float ( -- u ) \ gforth
42: \G @code{Constant} -- the number of address units corresponding to a floating-point number.
43: [THEN]
44:
45: 20 Constant bl ( -- c-char ) \ core b-l
46: \G @i{c-char} is the character value for a space.
47: \ used by docon:, must be constant
48:
49: FF Constant /line
50:
51: has? file [IF]
52: 40 Constant c/l
53: 10 Constant l/s
54: 400 Constant chars/block
55: [THEN]
56:
57: 20 8 2* cells + 2 + cell+ constant word-pno-size ( -- u )
58: create holdbuf word-pno-size chars allot
59: holdbuf word-pno-size chars + aconstant holdbuf-end
60: avariable holdptr holdbuf-end holdptr a!
61: avariable holdend holdbuf-end holdend a!
62:
63: 84 constant pad-minsize ( -- u )
64:
65: $400 Value def#tib
66: \G default size of terminal input buffer. Default size is 1K
67:
68: \ that's enough so long
69:
70: \ User variables 13feb93py
71:
72: \ initialized by COLD
73:
74: has? no-userspace 0= [IF]
75: Create main-task has? OS [IF] 100 [ELSE] 40 [THEN] cells dup allot
76:
77: \ set user-pointer from cross-compiler right
78: main-task
79: UNLOCK swap region user-region user-region setup-region LOCK
80:
81: Variable udp ( -- a-addr ) \ gforth
82: \G user area size
83:
84: AUser next-task main-task next-task !
85: AUser prev-task main-task prev-task !
86: AUser save-task 0 save-task !
87: [THEN]
88: AUser sp0 ( -- a-addr ) \ gforth
89: \G @code{User} variable -- initial value of the data stack pointer.
90: \ sp0 is used by douser:, must be user
91: \ ' sp0 Alias s0 ( -- a-addr ) \ gforth
92: \G OBSOLETE alias of @code{sp0}
93:
94: AUser rp0 ( -- a-addr ) \ gforth
95: \G @code{User} variable -- initial value of the return stack pointer.
96: \ ' rp0 Alias r0 ( -- a-addr ) \ gforth
97: \G OBSOLETE alias of @code{rp0}
98:
99: has? floating [IF]
100: AUser fp0 ( -- a-addr ) \ gforth
101: \G @code{User} variable -- initial value of the floating-point stack pointer.
102: \ no f0, because this leads to unexpected results when using hex
103: [THEN]
104:
105: has? glocals [IF]
106: AUser lp0 ( -- a-addr ) \ gforth
107: \G @code{User} variable -- initial value of the locals stack pointer.
108: \ ' lp0 Alias l0 ( -- a-addr ) \ gforth
109: \G OBSOLETE alias of @code{lp0}
110: [THEN]
111:
112: AUser handler \ pointer to last throw frame
113: has? backtrace [IF]
114: User backtrace-empty \ true if the next THROW should store a backtrace
115: AUser backtrace-rp0 \ rp at last call of interpret
116: [THEN]
117: \ AUser output
118: \ AUser input
119:
120: AUser errorhandler
121:
122: AUser "error 0 "error !
123:
124: has? new-input [IF]
125: User current-input
126: [ELSE]
127: [IFUNDEF] #tib \ in ec-Version we may define this ourself
128: User tibstack \ saves >tib in execute
129: User >tib \ pointer to terminal input buffer
130: User #tib ( -- a-addr ) \ core-ext number-t-i-b
131: \G @code{User} variable -- @i{a-addr} is the address of a cell containing
132: \G the number of characters in the terminal input buffer.
133: \G OBSOLESCENT: @code{source} superceeds the function of this word.
134:
135: User >in ( -- a-addr ) \ core to-in
136: \G @code{User} variable -- @i{a-addr} is the address of a cell containing the
137: \G char offset from the start of the input buffer to the start of the
138: \G parse area.
139: 0 >in ! \ char number currently processed in tib
140: [THEN]
141:
142: has? file [IF]
143: User blk ( -- a-addr ) \ block b-l-k
144: \G @code{User} variable -- @i{a-addr} is the address of a cell containing zero
145: \G (in which case the input source is not a block and can be identified
146: \G by @code{source-id}) or the number of the block currently being
147: \G interpreted. A Standard program should not alter @code{blk} directly.
148: 0 blk !
149:
150: User loadfile 0 loadfile !
151:
152: 2user loadfilename 0 0 loadfilename 2! \ addr u for sourcefilename
153:
154: User loadline \ number of the currently interpreted
155: \ (in TIB) line if the interpretation
156: \ is in a textfile
157: \ the first line is 1
158:
159: 2User linestart \ starting file postition of
160: \ the current interpreted line (in TIB)
161: [THEN]
162: [THEN]
163:
164: 2user includefilename 0 0 includefilename 2! \ innermost included file
165:
166:
167: User base ( -- a-addr ) \ core
168: \G @code{User} variable -- @i{a-addr} is the address of a cell that stores the
169: \G number base used by default for number conversion during input and output.
170: A base !
171: User dpl ( -- a-addr ) \ gforth
172: \G @code{User} variable -- @i{a-addr} is the address of a cell that stores the
173: \G position of the decimal point in the most recent numeric conversion.
174: \G Initialised to -1. After the conversion of a number containing no
175: \G decimal point, @code{dpl} is -1. After the conversion of @code{2.} it holds
176: \G 0. After the conversion of 234123.9 it contains 1, and so forth.
177: -1 dpl !
178:
179: User state ( -- a-addr ) \ core,tools-ext
180: \G @code{User} variable -- @i{a-addr} is the address of a cell
181: \G containing the compilation state flag. 0 => interpreting, -1 =>
182: \G compiling. A program shall not directly alter the value of
183: \G @code{state}. The following Standard words alter the value in
184: \G @code{state}: @code{:} (colon) @code{;} (semicolon) @code{abort}
185: \G @code{quit} @code{:noname} @code{[} (left-bracket) @code{]}
186: \G (right-bracket) @code{;code}. Don't use @code{state}! For an
187: \G alternative see @ref{Interpretation and Compilation Semantics}.
188: \ Recommended reading: @cite{@code{State}-smartness--Why it is evil
189: \ and how to exorcise it},
190: \ @url{http://www.complang.tuwien.ac.at/papers/ertl98.ps.gz}; short
191: \ version: Don't use @code{state}!
192: 0 state !
193:
194: AUser normal-dp \ the usual dictionary pointer
195: AUser dpp normal-dp dpp !
196: \ the pointer to the current dictionary pointer
197: \ ist reset to normal-dp on (doerror)
198: \ (i.e. any throw caught by quit)
199: AUser LastCFA
200: AUser Last
201:
202: User max-name-length \ maximum length of all names defined yet
203: 32 max-name-length !
204:
205: \ has? peephole [IF]
206: \ 0 value peeptable \ initialized in boot
207: \ [THEN]
208:
209: has? glocals [IF]
210: User locals-size \ this is the current size of the locals stack
211: \ frame of the current word
212: [THEN]
213:
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