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