Annotation of gforth/kernel-ec/vars.fs, revision 1.1

1.1     ! pazsan      1: \ VARS.FS      Kernal variables
        !             2: 
        !             3: \ Copyright (C) 1995,1996,1997,1998,2000,2003,2006,2007,2011 Free Software Foundation, Inc.
        !             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 3
        !            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, see http://www.gnu.org/licenses/.
        !            19: 
        !            20: hex \ everything now hex!                               11may93jaw
        !            21: 
        !            22: \ important constants                                  17dec92py
        !            23: 
        !            24: \ dpANS6 (sect 3.1.3.1) says 
        !            25: \ "a true flag ... [is] a single-cell value with all bits set"
        !            26: \ better definition: 0 0= constant true ( no dependence on 2's compl)
        !            27:  -1 Constant true ( -- f ) \ core-ext
        !            28: \G @code{Constant} -- @i{f} is a cell with all bits set.
        !            29: \ see starts looking for primitives after this word!
        !            30: 
        !            31:   0 Constant false ( -- f ) \ core-ext
        !            32: \G @code{Constant} -- @i{f} is a cell with all bits clear.
        !            33: 
        !            34: [IFUNDEF] cell 
        !            35: 1 cells Constant cell ( -- u ) \ gforth
        !            36: \G @code{Constant} -- @code{1 cells}
        !            37: [THEN]
        !            38: 
        !            39: has? floating [IF]
        !            40: 1 floats Constant float ( -- u ) \ gforth
        !            41: \G @code{Constant} -- the number of address units corresponding to a floating-point number.
        !            42: [THEN]
        !            43: 
        !            44: 20 Constant bl ( -- c-char ) \ core b-l
        !            45: \G @i{c-char} is the character value for a space.
        !            46: \ used by docon:, must be constant
        !            47: 
        !            48: has? EC [IF] 20 cells [ELSE] FF [THEN] Constant /line
        !            49: 
        !            50: has? file [IF]
        !            51: 40 Value c/l
        !            52: 10 Value l/s
        !            53: 400 Value chars/block
        !            54: [THEN]
        !            55: 
        !            56: 20 8 2* cells + 2 + cell+ constant word-pno-size ( -- u )
        !            57: 
        !            58: 84 constant pad-minsize ( -- u )
        !            59: 
        !            60: $400 Value def#tib
        !            61: \G default size of terminal input buffer. Default size is 1K
        !            62: 
        !            63: \ that's enough so long
        !            64: 
        !            65: \ User variables                                       13feb93py
        !            66: 
        !            67: \ initialized by COLD
        !            68: 
        !            69: has? no-userspace 0= [IF]
        !            70: Create main-task  has? OS [IF] 100 [ELSE] 40 [THEN] cells dup allot
        !            71: 
        !            72: \ set user-pointer from cross-compiler right
        !            73: main-task 
        !            74: UNLOCK swap region user-region user-region setup-region LOCK
        !            75: 
        !            76: Variable udp ( -- a-addr ) \ gforth
        !            77: \G user area size
        !            78: 
        !            79: AUser next-task        main-task next-task !
        !            80: AUser prev-task        main-task prev-task !
        !            81: AUser save-task        0 save-task !
        !            82: [THEN]
        !            83: AUser sp0 ( -- a-addr ) \ gforth
        !            84: \G @code{User} variable -- initial value of the data stack pointer.
        !            85: \ sp0 is used by douser:, must be user
        !            86: \    ' sp0 Alias s0 ( -- a-addr ) \ gforth
        !            87: \G OBSOLETE alias of @code{sp0}
        !            88: 
        !            89: AUser rp0 ( -- a-addr ) \ gforth
        !            90: \G @code{User} variable -- initial value of the return stack pointer.
        !            91: \    ' rp0 Alias r0 ( -- a-addr ) \ gforth
        !            92: \G OBSOLETE alias of @code{rp0}
        !            93: 
        !            94: has? floating [IF]
        !            95: AUser fp0 ( -- a-addr ) \ gforth
        !            96: \G @code{User} variable -- initial value of the floating-point stack pointer.
        !            97: \ no f0, because this leads to unexpected results when using hex
        !            98: [THEN]
        !            99: 
        !           100: has? glocals [IF]
        !           101: AUser lp0 ( -- a-addr ) \ gforth
        !           102: \G @code{User} variable -- initial value of the locals stack pointer.
        !           103: \    ' lp0 Alias l0 ( -- a-addr ) \ gforth
        !           104: \G OBSOLETE alias of @code{lp0}
        !           105: [THEN]
        !           106: 
        !           107: AUser throw-entry  \ pointer to task-specific signal handler
        !           108: 
        !           109: AUser handler  \ pointer to last throw frame
        !           110: has? backtrace [IF]
        !           111: AUser backtrace-rp0 \ rp at last call of interpret
        !           112: [THEN]
        !           113: \ AUser output
        !           114: \ AUser input
        !           115: 
        !           116: AUser errorhandler
        !           117: 
        !           118: AUser "error            0 "error !
        !           119: 
        !           120: has? EC 0= [IF]
        !           121:     auser holdbufptr
        !           122:     here word-pno-size chars allot dup holdbufptr !
        !           123:     word-pno-size chars +
        !           124:     : holdbuf ( -- addr ) holdbufptr @ ;
        !           125:     : holdbuf-end   holdbuf word-pno-size chars + ;
        !           126:     auser holdptr dup holdptr a!
        !           127:     auser holdend     holdend a!
        !           128: [THEN]
        !           129: 
        !           130: has? new-input [IF]
        !           131:     User current-input
        !           132: [ELSE]
        !           133:     [IFUNDEF] #tib             \ in ec-Version we may define this ourself
        !           134:        User tibstack           \ saves >tib in execute
        !           135:        User >tib               \ pointer to terminal input buffer
        !           136:        User #tib ( -- a-addr ) \ core-ext number-t-i-b
        !           137:        \G @code{User} variable -- @i{a-addr} is the address of a cell containing
        !           138:        \G the number of characters in the terminal input buffer.
        !           139:        \G OBSOLESCENT: @code{source} superceeds the function of this word.
        !           140:        
        !           141:        User >in ( -- a-addr ) \ core to-in
        !           142:        \G @code{User} variable -- @i{a-addr} is the address of a cell containing the
        !           143:        \G char offset from the start of the input buffer to the start of the
        !           144:        \G parse area.
        !           145:        0 >in ! \ char number currently processed in tib
        !           146:     [THEN]
        !           147: 
        !           148: has? file [IF]
        !           149:  User blk ( -- a-addr ) \ block b-l-k
        !           150:  \G @code{User} variable -- @i{a-addr} is the address of a cell containing zero
        !           151:  \G (in which case the input source is not a block and can be identified
        !           152:  \G by @code{source-id}) or the number of the block currently being
        !           153:  \G interpreted. A Standard program should not alter @code{blk} directly.
        !           154:                        0 blk !
        !           155: 
        !           156:  User loadfile          0 loadfile !
        !           157: 
        !           158:  2user loadfilename    0 0 loadfilename 2! \ addr u for sourcefilename
        !           159:      
        !           160:  User loadline          \ number of the currently interpreted
        !           161:                         \ (in TIB) line if the interpretation
        !           162:                         \ is in a textfile
        !           163:                         \ the first line is 1
        !           164: 
        !           165: 2User linestart         \ starting file postition of
        !           166:                         \ the current interpreted line (in TIB)
        !           167: [THEN]
        !           168: [THEN]
        !           169: 
        !           170:  2user includefilename  0 0 includefilename 2! \ innermost included file
        !           171: 
        !           172: 
        !           173: User base ( -- a-addr ) \ core
        !           174: \G @code{User} variable -- @i{a-addr} is the address of a cell that
        !           175: \G stores the number base used by default for number conversion during
        !           176: \G input and output.  Don't store to @code{base}, use
        !           177: \G @code{base-execute} instead.
        !           178:                        A base !
        !           179: User dpl ( -- a-addr ) \ gforth
        !           180: \G @code{User} variable -- @i{a-addr} is the address of a cell that stores the                 
        !           181: \G position of the decimal point in the most recent numeric conversion.
        !           182: \G Initialised to -1. After the conversion of a number containing no
        !           183: \G decimal point, @code{dpl} is -1. After the conversion of @code{2.} it holds
        !           184: \G 0. After the conversion of 234123.9 it contains 1, and so forth.
        !           185: -1 dpl !
        !           186: 
        !           187: User dp-char ( -- a-addr ) \ VFX
        !           188: \G @code{User} variable -- @i{a-addr} is the address of a cell that stores the
        !           189: \G decimal point character for double number conversion
        !           190: '.' dp-char !
        !           191: 
        !           192: User fp-char ( -- a-addr ) \ VFX
        !           193: \G @code{User} variable -- @i{a-addr} is the address of a cell that stores the
        !           194: \G decimal point character for floating point number conversion
        !           195: '.' fp-char !
        !           196: 
        !           197: User state ( -- a-addr ) \ core,tools-ext
        !           198: \G @code{User} variable -- @i{a-addr} is the address of a cell
        !           199: \G containing the compilation state flag. 0 => interpreting, -1 =>
        !           200: \G compiling.  A program shall not directly alter the value of
        !           201: \G @code{state}. The following Standard words alter the value in
        !           202: \G @code{state}: @code{:} (colon) @code{;} (semicolon) @code{abort}
        !           203: \G @code{quit} @code{:noname} @code{[} (left-bracket) @code{]}
        !           204: \G (right-bracket) @code{;code}. Don't use @code{state}! For an
        !           205: \G alternative see @ref{Interpretation and Compilation Semantics}.
        !           206: \ Recommended reading: @cite{@code{State}-smartness--Why it is evil
        !           207: \ and how to exorcise it},
        !           208: \ @url{http://www.complang.tuwien.ac.at/papers/ertl98.ps.gz}; short
        !           209: \ version: Don't use @code{state}!
        !           210: 0 state !
        !           211: 
        !           212: AUser normal-dp                \ the usual dictionary pointer
        !           213: AUser dpp              normal-dp dpp !
        !           214:                        \ the pointer to the current dictionary pointer
        !           215:                         \ ist reset to normal-dp on (doerror)
        !           216:                         \  (i.e. any throw caught by quit)
        !           217: has? ec [IF]
        !           218:     AUser LastCFA
        !           219: [THEN]
        !           220: AUser Last
        !           221: 
        !           222: has? flash [IF]
        !           223:     AUser flash-dp
        !           224:     : rom  flash-dp dpp ! ;
        !           225:     : ram  normal-dp dpp ! ;
        !           226: [THEN]
        !           227: 
        !           228: User max-name-length \ maximum length of all names defined yet
        !           229: 32 max-name-length !
        !           230:     
        !           231: \  has? peephole  [IF]
        !           232: \  0 value peeptable \ initialized in boot
        !           233: \  [THEN]
        !           234: 
        !           235: has? glocals [IF]
        !           236: User locals-size \ this is the current size of the locals stack
        !           237:                 \ frame of the current word
        !           238: [THEN]
        !           239: 

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