Annotation of gforth/kernel/vars.fs, revision 1.16
1.1 anton 1: \ VARS.FS Kernal variables
2:
1.6 anton 3: \ Copyright (C) 1995,1996,1997,1998 Free Software Foundation, Inc.
1.1 anton 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., 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)
1.10 crook 28: -1 Constant true ( -- f ) \ core-ext
1.14 crook 29: \G CONSTANT: @var{f} is a cell with all bits set.
1.10 crook 30: \ see starts looking for primitives after this word!
31:
32: 0 Constant false ( -- f ) \ core-ext
1.14 crook 33: \G CONSTANT: @var{f} is a cell with all bits clear.
1.1 anton 34:
1.16 ! jwilke 35: [IFUNDEF] cell
1.1 anton 36: 1 cells Constant cell ( -- u ) \ gforth
1.16 ! jwilke 37: [THEN]
1.1 anton 38: 1 floats Constant float ( -- u ) \ gforth
39:
1.10 crook 40: 20 Constant bl ( -- c-char ) \ core
1.14 crook 41: \G @var{c-char} is the character value for a space.
1.10 crook 42: \ used by docon:, must be constant
1.1 anton 43:
44: FF Constant /line
45:
46: 40 Constant c/l
47: 10 Constant l/s
48: 400 Constant chars/block
49:
1.2 anton 50: $20 8 2* cells + 2 + cell+ constant word-pno-size ( -- u )
1.11 anton 51: create holdbuf word-pno-size chars allot
52: holdbuf word-pno-size chars + aconstant holdbuf-end
53: avariable holdptr holdbuf-end holdptr a!
1.12 anton 54: avariable holdend holdbuf-end holdend a!
1.11 anton 55:
1.2 anton 56: 84 constant pad-minsize ( -- u )
1.11 anton 57:
1.2 anton 58:
1.1 anton 59: \ that's enough so long
60:
61: \ User variables 13feb93py
62:
63: \ initialized by COLD
64:
1.7 pazsan 65: Create main-task has? OS [IF] 100 [ELSE] 40 [THEN] cells allot
1.3 jwilke 66:
67: \ set user-pointer from cross-compiler right
68: main-task
69: UNLOCK tup ! LOCK
1.1 anton 70:
1.8 anton 71: Variable udp \ user area size? -anton
1.1 anton 72:
73: AUser next-task main-task next-task !
74: AUser prev-task main-task prev-task !
75: AUser save-task 0 save-task !
1.10 crook 76: AUser sp0 ( -- a-addr ) \ gforth
77: \G USER VARIABLE: Initial value of the data stack pointer.
78: \ sp0 is used by douser:, must be user
79: ' sp0 Alias s0 ( -- a-addr ) \ gforth
80: \G OBSOLETE alias of @code{sp0}
81:
82: AUser rp0 ( -- a-addr ) \ gforth
83: \G USER VARIABLE: Initial value of the return stack pointer.
84: ' rp0 Alias r0 ( -- a-addr ) \ gforth
85: \G OBSOLETE alias of @code{rp0}
86:
87: AUser fp0 ( -- a-addr ) \ gforth
88: \G USER VARIABLE: Initial value of the floating-point stack pointer.
89: \ no f0, because this leads to unexpected results when using hex
90:
91: AUser lp0 ( -- a-addr ) \ gforth
92: \G USER VARIABLE: Initial value of the locals stack pointer.
93: ' lp0 Alias l0 ( -- a-addr ) \ gforth
94: \G OBSOLETE alias of @code{lp0}
95:
1.3 jwilke 96: AUser handler \ pointer to last throw frame
1.13 anton 97: User backtrace-empty \ true if the next THROW should store a backtrace
98: AUser backtrace-rp0 \ rp at last call of interpret
1.1 anton 99: \ AUser output
100: \ AUser input
101:
102: AUser errorhandler
103:
104: AUser "error 0 "error !
105:
1.3 jwilke 106: [IFUNDEF] #tib \ in ec-Version we may define this ourself
107: User tibstack \ saves >tib in execute
108: User >tib \ pointer to terminal input buffer
1.10 crook 109: User #tib ( -- a-addr ) \ core-ext
1.14 crook 110: \G USER VARIABLE: @var{a-addr} is the address of a cell containing
1.10 crook 111: \G the number of characters in the terminal input buffer.
112: \G OBSOLESCENT: @code{source} superceeds the function of this word.
113:
114: User >in ( -- a-addr ) \ core
1.14 crook 115: \G USER VARIABLE: @var{a-addr} is the address of a cell containing the
1.10 crook 116: \G char offset from the start of the terminal input buffer to the
1.15 crook 117: \G start of the parse area.
1.10 crook 118: 0 >in ! \ char number currently processed in tib
1.3 jwilke 119: [THEN]
1.7 pazsan 120: has? file [IF]
1.10 crook 121: User blk ( -- a-addr ) \ block
1.14 crook 122: \G USER VARIABLE: @var{a-addr} is the address of a cell containing zero
1.10 crook 123: \G (in which case the input source is not a block and can be identified
124: \G by @code{source-id}) or the number of the block currently being
125: \G interpreted. A Standard program should not alter @code{blk} directly.
126: 0 blk !
127:
1.1 anton 128: User loadfile 0 loadfile !
129:
130: User loadfilename# 0 loadfilename# !
131:
132: User loadline \ number of the currently interpreted
133: \ (in TIB) line if the interpretation
134: \ is in a textfile
135: \ the first line is 1
136:
137: 2User linestart \ starting file postition of
138: \ the current interpreted line (in TIB)
1.7 pazsan 139: [THEN]
1.1 anton 140:
1.10 crook 141: User base ( -- a-addr ) \ core
1.14 crook 142: \G USER VARIABLE: @var{a-addr} is the address of a cell that stores the
1.10 crook 143: \G number base used by default for number conversion during input and output.
144: A base !
1.1 anton 145: User dpl -1 dpl !
146:
1.10 crook 147: User state ( -- a-addr ) \ core,tools-ext
1.12 anton 148: \G Recommended reading: @cite{@code{State}-smartness--Why it is evil
149: \G and how to exorcise it},
150: \G @url{http://www.complang.tuwien.ac.at/papers/ertl98.ps.gz}; short
151: \G version: Don't use @code{state}! @xref{Interpretation and
1.14 crook 152: \G Compilation Semantics} for an alternative. USER VARIABLE: @var{a-addr}
1.12 anton 153: \G is the address of a cell containing the compilation state flag. 0
154: \G => interpreting, -1 => compiling. A program shall not directly
155: \G alter the value of @code{state}. The following Standard words
156: \G alter the value in @code{state}: @code{:} (colon) @code{;}
157: \G (semicolon) @code{abort} @code{quit} @code{:noname} @code{[}
158: \G (left-bracket) @code{]} (right-bracket) @code{;code}
1.10 crook 159: 0 state !
160:
1.1 anton 161: AUser normal-dp \ the usual dictionary pointer
162: AUser dpp normal-dp dpp !
163: \ the pointer to the current dictionary pointer
164: \ ist reset to normal-dp on (doerror)
165: \ (i.e. any throw caught by quit)
166: AUser LastCFA
167: AUser Last
168:
1.7 pazsan 169: has? glocals [IF]
1.1 anton 170: User locals-size \ this is the current size of the locals stack
171: \ frame of the current word
1.7 pazsan 172: [THEN]
1.1 anton 173:
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