Annotation of gforth/kernel/vars.fs, revision 1.17
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
1.17 ! crook 29: \G CONSTANT: @i{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
1.17 ! crook 33: \G CONSTANT: @i{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
1.17 ! crook 37: \G CONSTANT: the number of address units corresponding to 1 cell.
1.16 jwilke 38: [THEN]
1.17 ! crook 39:
1.1 anton 40: 1 floats Constant float ( -- u ) \ gforth
1.17 ! crook 41: \G CONSTANT: the number of address units corresponding to a floating-point number.
1.1 anton 42:
1.10 crook 43: 20 Constant bl ( -- c-char ) \ core
1.17 ! crook 44: \G @i{c-char} is the character value for a space.
1.10 crook 45: \ used by docon:, must be constant
1.1 anton 46:
47: FF Constant /line
48:
49: 40 Constant c/l
50: 10 Constant l/s
51: 400 Constant chars/block
52:
1.2 anton 53: $20 8 2* cells + 2 + cell+ constant word-pno-size ( -- u )
1.11 anton 54: create holdbuf word-pno-size chars allot
55: holdbuf word-pno-size chars + aconstant holdbuf-end
56: avariable holdptr holdbuf-end holdptr a!
1.12 anton 57: avariable holdend holdbuf-end holdend a!
1.11 anton 58:
1.2 anton 59: 84 constant pad-minsize ( -- u )
1.11 anton 60:
1.2 anton 61:
1.1 anton 62: \ that's enough so long
63:
64: \ User variables 13feb93py
65:
66: \ initialized by COLD
67:
1.7 pazsan 68: Create main-task has? OS [IF] 100 [ELSE] 40 [THEN] cells allot
1.3 jwilke 69:
70: \ set user-pointer from cross-compiler right
71: main-task
72: UNLOCK tup ! LOCK
1.1 anton 73:
1.8 anton 74: Variable udp \ user area size? -anton
1.1 anton 75:
76: AUser next-task main-task next-task !
77: AUser prev-task main-task prev-task !
78: AUser save-task 0 save-task !
1.10 crook 79: AUser sp0 ( -- a-addr ) \ gforth
80: \G USER VARIABLE: Initial value of the data stack pointer.
81: \ sp0 is used by douser:, must be user
82: ' sp0 Alias s0 ( -- a-addr ) \ gforth
83: \G OBSOLETE alias of @code{sp0}
84:
85: AUser rp0 ( -- a-addr ) \ gforth
86: \G USER VARIABLE: Initial value of the return stack pointer.
87: ' rp0 Alias r0 ( -- a-addr ) \ gforth
88: \G OBSOLETE alias of @code{rp0}
89:
90: AUser fp0 ( -- a-addr ) \ gforth
91: \G USER VARIABLE: Initial value of the floating-point stack pointer.
92: \ no f0, because this leads to unexpected results when using hex
93:
94: AUser lp0 ( -- a-addr ) \ gforth
95: \G USER VARIABLE: Initial value of the locals stack pointer.
96: ' lp0 Alias l0 ( -- a-addr ) \ gforth
97: \G OBSOLETE alias of @code{lp0}
98:
1.3 jwilke 99: AUser handler \ pointer to last throw frame
1.13 anton 100: User backtrace-empty \ true if the next THROW should store a backtrace
101: AUser backtrace-rp0 \ rp at last call of interpret
1.1 anton 102: \ AUser output
103: \ AUser input
104:
105: AUser errorhandler
106:
107: AUser "error 0 "error !
108:
1.3 jwilke 109: [IFUNDEF] #tib \ in ec-Version we may define this ourself
110: User tibstack \ saves >tib in execute
111: User >tib \ pointer to terminal input buffer
1.10 crook 112: User #tib ( -- a-addr ) \ core-ext
1.17 ! crook 113: \G USER VARIABLE: @i{a-addr} is the address of a cell containing
1.10 crook 114: \G the number of characters in the terminal input buffer.
115: \G OBSOLESCENT: @code{source} superceeds the function of this word.
116:
117: User >in ( -- a-addr ) \ core
1.17 ! crook 118: \G USER VARIABLE: @i{a-addr} is the address of a cell containing the
! 119: \G char offset from the start of the input buffer to the start of the
! 120: \G parse area.
1.10 crook 121: 0 >in ! \ char number currently processed in tib
1.3 jwilke 122: [THEN]
1.7 pazsan 123: has? file [IF]
1.10 crook 124: User blk ( -- a-addr ) \ block
1.17 ! crook 125: \G USER VARIABLE: @i{a-addr} is the address of a cell containing zero
1.10 crook 126: \G (in which case the input source is not a block and can be identified
127: \G by @code{source-id}) or the number of the block currently being
128: \G interpreted. A Standard program should not alter @code{blk} directly.
129: 0 blk !
130:
1.1 anton 131: User loadfile 0 loadfile !
132:
133: User loadfilename# 0 loadfilename# !
134:
135: User loadline \ number of the currently interpreted
136: \ (in TIB) line if the interpretation
137: \ is in a textfile
138: \ the first line is 1
139:
140: 2User linestart \ starting file postition of
141: \ the current interpreted line (in TIB)
1.7 pazsan 142: [THEN]
1.1 anton 143:
1.10 crook 144: User base ( -- a-addr ) \ core
1.17 ! crook 145: \G USER VARIABLE: @i{a-addr} is the address of a cell that stores the
1.10 crook 146: \G number base used by default for number conversion during input and output.
147: A base !
1.17 ! crook 148: User dpl ( -- a-addr ) \ gforth
! 149: \G USER VARIABLE: @i{a-addr} is the address of a cell that stores the
! 150: \G position of the decimal point in the most recent numeric conversion.
! 151: \G Initialised to -1. After the conversion of a number containing no
! 152: \G decimal point, @code{@ dpl} is -1. After the conversion of @code{2.} it holds
! 153: \G 0. After the conversion of 234123.9 it contains 1, and so forth.
! 154: -1 dpl !
1.1 anton 155:
1.10 crook 156: User state ( -- a-addr ) \ core,tools-ext
1.17 ! crook 157: \G USER VARIABLE: @i{a-addr} is the address of a cell containing the
! 158: \G compilation state flag. 0 => interpreting, -1 => compiling. A
! 159: \G program shall not directly alter the value of @code{state}. The
! 160: \G following Standard words alter the value in @code{state}: @code{:}
! 161: \G (colon) @code{;} (semicolon) @code{abort} @code{quit}
! 162: \G @code{:noname} @code{[} (left-bracket) @code{]} (right-bracket)
! 163: \G @code{;code}. Don't use @code{state}! @xref{Interpretation and
! 164: \G Compilation Semantics} for an alternative.
! 165: \ Recommended reading: @cite{@code{State}-smartness--Why it is evil
! 166: \ and how to exorcise it},
! 167: \ @url{http://www.complang.tuwien.ac.at/papers/ertl98.ps.gz}; short
! 168: \ version: Don't use @code{state}!
! 169: 0 state !
1.10 crook 170:
1.1 anton 171: AUser normal-dp \ the usual dictionary pointer
172: AUser dpp normal-dp dpp !
173: \ the pointer to the current dictionary pointer
174: \ ist reset to normal-dp on (doerror)
175: \ (i.e. any throw caught by quit)
176: AUser LastCFA
177: AUser Last
178:
1.7 pazsan 179: has? glocals [IF]
1.1 anton 180: User locals-size \ this is the current size of the locals stack
181: \ frame of the current word
1.7 pazsan 182: [THEN]
1.1 anton 183:
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