Annotation of gforth/kernel/vars.fs, revision 1.38

1.1       anton       1: \ VARS.FS      Kernal variables
                      2: 
1.34      anton       3: \ Copyright (C) 1995,1996,1997,1998,2000,2003 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
1.24      anton      19: \ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
1.1       anton      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
1.19      crook      29: \G @code{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
1.19      crook      33: \G @code{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
1.22      anton      37: \G @code{Constant} -- @code{1 cells}
1.16      jwilke     38: [THEN]
1.17      crook      39: 
1.25      pazsan     40: has? floating [IF]
1.1       anton      41: 1 floats Constant float ( -- u ) \ gforth
1.19      crook      42: \G @code{Constant} -- the number of address units corresponding to a floating-point number.
1.25      pazsan     43: [THEN]
1.1       anton      44: 
1.20      crook      45: 20 Constant bl ( -- c-char ) \ core b-l
1.17      crook      46: \G @i{c-char} is the character value for a space.
1.10      crook      47: \ used by docon:, must be constant
1.1       anton      48: 
                     49: FF Constant /line
                     50: 
1.38    ! pazsan     51: has? files [IF]
1.1       anton      52: 40 Constant c/l
                     53: 10 Constant l/s
                     54: 400 Constant chars/block
1.38    ! pazsan     55: [THEN]
1.1       anton      56: 
1.18      jwilke     57: 20 8 2* cells + 2 + cell+ constant word-pno-size ( -- u )
1.11      anton      58: create holdbuf word-pno-size chars allot
                     59: holdbuf word-pno-size chars + aconstant holdbuf-end
                     60: avariable holdptr holdbuf-end holdptr a!
1.12      anton      61: avariable holdend holdbuf-end holdend a!
1.11      anton      62: 
1.2       anton      63: 84 constant pad-minsize ( -- u )
1.11      anton      64: 
1.25      pazsan     65: $400 Value def#tib
                     66: \G default size of terminal input buffer. Default size is 1K
1.2       anton      67: 
1.1       anton      68: \ that's enough so long
                     69: 
                     70: \ User variables                                       13feb93py
                     71: 
                     72: \ initialized by COLD
                     73: 
1.38    ! pazsan     74: has? no-userspace 0= [IF]
1.35      jwilke     75: Create main-task  has? OS [IF] 100 [ELSE] 40 [THEN] cells dup allot
1.3       jwilke     76: 
                     77: \ set user-pointer from cross-compiler right
                     78: main-task 
1.35      jwilke     79: UNLOCK swap region user-region user-region setup-region LOCK
1.1       anton      80: 
1.19      crook      81: Variable udp ( -- a-addr ) \ gforth
1.28      pazsan     82: \G user area size
1.1       anton      83: 
                     84: AUser next-task        main-task next-task !
                     85: AUser prev-task        main-task prev-task !
                     86: AUser save-task        0 save-task !
1.38    ! pazsan     87: [THEN]
1.10      crook      88: AUser sp0 ( -- a-addr ) \ gforth
1.19      crook      89: \G @code{User} variable -- initial value of the data stack pointer.
1.10      crook      90: \ sp0 is used by douser:, must be user
1.38    ! pazsan     91: \    ' sp0 Alias s0 ( -- a-addr ) \ gforth
1.10      crook      92: \G OBSOLETE alias of @code{sp0}
                     93: 
                     94: AUser rp0 ( -- a-addr ) \ gforth
1.19      crook      95: \G @code{User} variable -- initial value of the return stack pointer.
1.38    ! pazsan     96: \    ' rp0 Alias r0 ( -- a-addr ) \ gforth
1.10      crook      97: \G OBSOLETE alias of @code{rp0}
                     98: 
1.25      pazsan     99: has? floating [IF]
1.10      crook     100: AUser fp0 ( -- a-addr ) \ gforth
1.19      crook     101: \G @code{User} variable -- initial value of the floating-point stack pointer.
1.10      crook     102: \ no f0, because this leads to unexpected results when using hex
1.25      pazsan    103: [THEN]
1.10      crook     104: 
1.25      pazsan    105: has? glocals [IF]
1.10      crook     106: AUser lp0 ( -- a-addr ) \ gforth
1.19      crook     107: \G @code{User} variable -- initial value of the locals stack pointer.
1.38    ! pazsan    108: \    ' lp0 Alias l0 ( -- a-addr ) \ gforth
1.10      crook     109: \G OBSOLETE alias of @code{lp0}
1.25      pazsan    110: [THEN]
1.10      crook     111: 
1.3       jwilke    112: AUser handler  \ pointer to last throw frame
1.18      jwilke    113: has? backtrace [IF]
1.13      anton     114: User backtrace-empty \ true if the next THROW should store a backtrace
                    115: AUser backtrace-rp0 \ rp at last call of interpret
1.18      jwilke    116: [THEN]
1.1       anton     117: \ AUser output
                    118: \ AUser input
                    119: 
                    120: AUser errorhandler
                    121: 
                    122: AUser "error            0 "error !
                    123: 
1.25      pazsan    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: 
1.7       pazsan    142: has? file [IF]
1.20      crook     143:  User blk ( -- a-addr ) \ block b-l-k
1.19      crook     144:  \G @code{User} variable -- @i{a-addr} is the address of a cell containing zero
1.10      crook     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: 
1.1       anton     150:  User loadfile          0 loadfile !
                    151: 
1.32      anton     152:  2user loadfilename    0 0 loadfilename 2! \ addr u for sourcefilename
1.37      anton     153:      
1.1       anton     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)
1.25      pazsan    161: [THEN]
1.7       pazsan    162: [THEN]
1.37      anton     163: 
                    164:  2user includefilename  0 0 includefilename 2! \ innermost included file
                    165: 
1.1       anton     166: 
1.26      anton     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
1.36      anton     175: \G decimal point, @code{dpl} is -1. After the conversion of @code{2.} it holds
1.26      anton     176: \G 0. After the conversion of 234123.9 it contains 1, and so forth.
                    177: -1 dpl !
1.1       anton     178: 
1.26      anton     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 !
1.10      crook     193: 
1.1       anton     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
1.26      anton     201: 
1.33      anton     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]
1.1       anton     208: 
1.7       pazsan    209: has? glocals [IF]
1.1       anton     210: User locals-size \ this is the current size of the locals stack
                    211:                 \ frame of the current word
1.7       pazsan    212: [THEN]
1.1       anton     213: 

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