Annotation of gforth/kernel/vars.fs, revision 1.36

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: 
                     51: 40 Constant c/l
                     52: 10 Constant l/s
                     53: 400 Constant chars/block
                     54: 
1.18      jwilke     55: 20 8 2* cells + 2 + cell+ constant word-pno-size ( -- u )
1.11      anton      56: create holdbuf word-pno-size chars allot
                     57: holdbuf word-pno-size chars + aconstant holdbuf-end
                     58: avariable holdptr holdbuf-end holdptr a!
1.12      anton      59: avariable holdend holdbuf-end holdend a!
1.11      anton      60: 
1.2       anton      61: 84 constant pad-minsize ( -- u )
1.11      anton      62: 
1.25      pazsan     63: $400 Value def#tib
                     64: \G default size of terminal input buffer. Default size is 1K
1.2       anton      65: 
1.1       anton      66: \ that's enough so long
                     67: 
                     68: \ User variables                                       13feb93py
                     69: 
                     70: \ initialized by COLD
                     71: 
1.35      jwilke     72: Create main-task  has? OS [IF] 100 [ELSE] 40 [THEN] cells dup allot
1.3       jwilke     73: 
                     74: \ set user-pointer from cross-compiler right
                     75: main-task 
1.35      jwilke     76: UNLOCK swap region user-region user-region setup-region LOCK
1.1       anton      77: 
1.19      crook      78: Variable udp ( -- a-addr ) \ gforth
1.28      pazsan     79: \G user area size
1.1       anton      80: 
                     81: AUser next-task        main-task next-task !
                     82: AUser prev-task        main-task prev-task !
                     83: AUser save-task        0 save-task !
1.10      crook      84: AUser sp0 ( -- a-addr ) \ gforth
1.19      crook      85: \G @code{User} variable -- initial value of the data stack pointer.
1.10      crook      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
1.19      crook      91: \G @code{User} variable -- initial value of the return stack pointer.
1.10      crook      92:     ' rp0 Alias r0 ( -- a-addr ) \ gforth
                     93: \G OBSOLETE alias of @code{rp0}
                     94: 
1.25      pazsan     95: has? floating [IF]
1.10      crook      96: AUser fp0 ( -- a-addr ) \ gforth
1.19      crook      97: \G @code{User} variable -- initial value of the floating-point stack pointer.
1.10      crook      98: \ no f0, because this leads to unexpected results when using hex
1.25      pazsan     99: [THEN]
1.10      crook     100: 
1.25      pazsan    101: has? glocals [IF]
1.10      crook     102: AUser lp0 ( -- a-addr ) \ gforth
1.19      crook     103: \G @code{User} variable -- initial value of the locals stack pointer.
1.10      crook     104:     ' lp0 Alias l0 ( -- a-addr ) \ gforth
                    105: \G OBSOLETE alias of @code{lp0}
1.25      pazsan    106: [THEN]
1.10      crook     107: 
1.3       jwilke    108: AUser handler  \ pointer to last throw frame
1.18      jwilke    109: has? backtrace [IF]
1.13      anton     110: User backtrace-empty \ true if the next THROW should store a backtrace
                    111: AUser backtrace-rp0 \ rp at last call of interpret
1.18      jwilke    112: [THEN]
1.1       anton     113: \ AUser output
                    114: \ AUser input
                    115: 
                    116: AUser errorhandler
                    117: 
                    118: AUser "error            0 "error !
                    119: 
1.25      pazsan    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: 
1.7       pazsan    138: has? file [IF]
1.20      crook     139:  User blk ( -- a-addr ) \ block b-l-k
1.19      crook     140:  \G @code{User} variable -- @i{a-addr} is the address of a cell containing zero
1.10      crook     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: 
1.1       anton     146:  User loadfile          0 loadfile !
                    147: 
1.32      anton     148:  2user loadfilename    0 0 loadfilename 2! \ addr u for sourcefilename
1.1       anton     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)
1.25      pazsan    157: [THEN]
1.7       pazsan    158: [THEN]
1.1       anton     159: 
1.26      anton     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
1.36    ! anton     168: \G decimal point, @code{dpl} is -1. After the conversion of @code{2.} it holds
1.26      anton     169: \G 0. After the conversion of 234123.9 it contains 1, and so forth.
                    170: -1 dpl !
1.1       anton     171: 
1.26      anton     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 !
1.10      crook     186: 
1.1       anton     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
1.26      anton     194: 
1.33      anton     195: User max-name-length \ maximum length of all names defined yet
                    196: 32 max-name-length !
                    197:     
                    198: \  has? peephole  [IF]
                    199: \  0 value peeptable \ initialized in boot
                    200: \  [THEN]
1.1       anton     201: 
1.7       pazsan    202: has? glocals [IF]
1.1       anton     203: User locals-size \ this is the current size of the locals stack
                    204:                 \ frame of the current word
1.7       pazsan    205: [THEN]
1.1       anton     206: 

FreeBSD-CVSweb <freebsd-cvsweb@FreeBSD.org>