[gforth] / gforth / kernel / vars.fs  

gforth: gforth/kernel/vars.fs

1 : anton 1.1 \ VARS.FS Kernal variables
2 :    
3 : anton 1.6 \ Copyright (C) 1995,1996,1997,1998 Free Software Foundation, Inc.
4 : anton 1.1
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 : crook 1.10 -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 : anton 1.1
35 :     1 cells Constant cell ( -- u ) \ gforth
36 :     1 floats Constant float ( -- u ) \ gforth
37 :    
38 : crook 1.10 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 : anton 1.1
42 :     FF Constant /line
43 :    
44 :     40 Constant c/l
45 :     10 Constant l/s
46 :     400 Constant chars/block
47 :    
48 : anton 1.2 $20 8 2* cells + 2 + cell+ constant word-pno-size ( -- u )
49 : anton 1.11 create holdbuf word-pno-size chars allot
50 :     holdbuf word-pno-size chars + aconstant holdbuf-end
51 :     avariable holdptr holdbuf-end holdptr a!
52 : anton 1.12 avariable holdend holdbuf-end holdend a!
53 : anton 1.11
54 : anton 1.2 84 constant pad-minsize ( -- u )
55 : anton 1.11
56 : anton 1.2
57 : anton 1.1 \ that's enough so long
58 :    
59 :     \ User variables 13feb93py
60 :    
61 :     \ initialized by COLD
62 :    
63 : pazsan 1.7 Create main-task has? OS [IF] 100 [ELSE] 40 [THEN] cells allot
64 : jwilke 1.3
65 :     \ set user-pointer from cross-compiler right
66 :     main-task
67 :     UNLOCK tup ! LOCK
68 : anton 1.1
69 : anton 1.8 Variable udp \ user area size? -anton
70 : anton 1.1
71 :     AUser next-task main-task next-task !
72 :     AUser prev-task main-task prev-task !
73 :     AUser save-task 0 save-task !
74 : crook 1.10 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 : jwilke 1.3 AUser handler \ pointer to last throw frame
95 : anton 1.9 AUser backtrace-empty \ true if the next THROW should store a backtrace
96 : anton 1.1 \ AUser output
97 :     \ AUser input
98 :    
99 :     AUser errorhandler
100 :    
101 :     AUser "error 0 "error !
102 :    
103 : jwilke 1.3 [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 : crook 1.10 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 : jwilke 1.3 [THEN]
117 : pazsan 1.7 has? file [IF]
118 : crook 1.10 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 : anton 1.1 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 : pazsan 1.7 [THEN]
137 : anton 1.1
138 : crook 1.10 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 : anton 1.1 User dpl -1 dpl !
143 :    
144 : crook 1.10 User state ( -- a-addr ) \ core,tools-ext
145 : anton 1.12 \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 : crook 1.10 0 state !
157 :    
158 : anton 1.1 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 : pazsan 1.7 has? glocals [IF]
167 : anton 1.1 User locals-size \ this is the current size of the locals stack
168 :     \ frame of the current word
169 : pazsan 1.7 [THEN]
170 : anton 1.1
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