Annotation of gforth/kernel-ec/vars.fs, revision 1.2

1.1       pazsan      1: \ VARS.FS      Kernal variables
                      2: 
1.2     ! anton       3: \ Copyright (C) 1995,1996,1997,1998,2000,2003,2006,2007,2011,2012 Free Software Foundation, Inc.
1.1       pazsan      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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