Unterschiede

Hier werden die Unterschiede zwischen zwei Versionen angezeigt.

--- papierkorb:help.blk [2025-08-16 17:50] – ↷ Seite von projects:help.blk nach papierkorb:help.blk verschoben mka
+++ papierkorb:help.blk [Unbekanntes Datum] (aktuell) – gelöscht - Externe Bearbeitung (Unbekanntes Datum) 127.0.0.1
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-===On line HELP system===
-<code>
-Screen 0 not modified
-\ Help System                                  11:43JWB03/25/86
-\ Last change:   Screen  009                   11:45JWB03/25/86
-
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-Screen 1 not modified
-\ HELP SYSTEM LOAD SCREEN                      11:43JWB03/25/86
-
-  CR .( Loading HELP system.)
-
-   2  9   THRU
-
-
-
-
-
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-
-
-
-Screen 2 not modified
-\ HELP-0 HBLOCK PBLOCK DONE? IPROMPT MAXPR     11:07JWB12/01/85
-ONLY EDITOR ALSO FORTH ALSO HIDDEN DEFINITIONS
-   VARIABLE #PROMPT     \ Prompt # and index into help screens.
-   VARIABLE HBLOCK      \ Contains block # of first help screen.
-   VARIABLE FINI        \ Flag set true when it's time to quit.
-   VARIABLE MAXP        \ Contains max number of help screens.
-0 CONSTANT IPROMPT     \ Initial Prompt number.
-
-\ Leave number of last prompt.
-: MAXPROMPT ( --  n )
-         MAXP @ ;
-
-\ Leave true flag if user responds positively.
-: (Y/N?)  ( --  flag )
-   ." Yes/No " KEY DUP 223 ( $DF = 11011111 to allow lower case)
-   AND ASCII Y = SWAP BL = OR ;
-Screen 3 not modified
-\ HELP-1  (Y/N?)  (LIST) .HELP                 10:15JWB12/01/85
-\ List a screen without its header and line numbers.
-: (LIST) ( n  -- )
-         SCR ! CLEARSCREEN
-         16 0 DO 8 I 3 + AT
-                 SCR @ BLOCK I C/L * +
-                 C/L -TRAILING >TYPE CR
-              LOOP ;
-
-\ Display the current help screen.
-: .HELP  ( --  -- )
-         #PROMPT @ HBLOCK @ 1+ + (LIST)
-         20 21 AT BEEP ." More help? "
-         (Y/N?)   NOT  FINI ! ;
-: WHITE 112  ATRIB ! ;  \ Set background to White.
-: BLACK  15  ATRIB ! ;  \ Set backbround to black.
-Screen 4 not modified
-\ HELP-2 PROMPT-ADR .PROMPT-CUR +.PROMPT.C     10:10JWB12/01/85
-\ Compute address and character count for prompt number n.
-: PROMPT-ADR ( n  adr count )
-         32 * B/BUF /MOD
-         HBLOCK @ + BLOCK         \  Note   the  BLOCK !!!
-         SWAP + 32 -TRAILING ;
-\ Position cursor at correct position for current prompt and
-\ leave current prompt number n.
-: .PROMPT-CUR  ( --  n )
-         #PROMPT @ DUP 3 /MOD
-         SWAP 25 * SWAP  AT ;
-\ Increment prompt number by n and position cursor and leave new
-\ prompt number as n'.
-: +.PROMPT-CUR  ( n   n' )
-         #PROMPT @ + MAXPROMPT MOD #PROMPT !
-         .PROMPT-CUR  ;
-Screen 5 not modified
-\ HELP-3 .PROMPT .RPROMPT +.PROMPT .HPROMP     10:21JWB12/01/85
-\ Display prompt number n at current cursor position.
-: .PROMPT ( n  -- )
-         PROMPT-ADR  VTYPE ;
-\ As above but with blue background.
-: .RPROMPT ( n  -- )
-         PROMPT-ADR WHITE VTYPE BLACK ;
-\ Increment prompt number by n amd move to new prompt.
-: +.PROMPT ( n  -- )
-         .PROMPT-CUR .PROMPT
-        +.PROMPT-CUR .RPROMPT ;
-\ Move to home position and display prompt number 0 .
-: .HPROMPT ( --  -- )
-         #PROMPT OFF 0 +.PROMPT ;
-: .EPROMPT ( --  -- )  \ Move to last prompt.
-         MAXPROMPT 1- #PROMPT ! 0 +.PROMPT ;
-Screen 6 not modified
-\ HELP-4                                       11:00JWB12/01/85
-: .LPROMPT ( --  -- )  \ Move to last prompt on line.
-         2 #PROMPT @ 3 MOD - +.PROMPT ;
-: .FPROMPT ( --  -- )  \ Move to first prompt on line.
-         MAXPROMPT #PROMPT @ 3 MOD - +.PROMPT ;
-
-: MENU  ( --  -- )
-         #PROMPT @ CLEARSCREEN MAXPROMPT 0
-         DO I #PROMPT ! .PROMPT-CUR .PROMPT LOOP 9 22 AT
-         ." Select with arrow keys and then press RETURN "
-         #PROMPT ! .PROMPT-CUR .RPROMPT ;
-
-: SCAN  ( false   flag )
-         200 0 DO DROP (KEY?) DUP ?LEAVE LOOP ;
-
-
-Screen 7 not modified
-\ HELP-5                                       11:04JWB12/01/85
-\ Same as PCKEY in line editor.
-: HCKEY ( --   n flag )
-         {KEY}
-             ?DUP IF TRUE ELSE {KEY} FALSE THEN ;
-
-
-: FKEY
-         (KEY?) IF HCKEY ELSE
-         BEGIN FALSE .PROMPT-CUR .PROMPT SCAN
-               .PROMPT-CUR .RPROMPT DUP NOT
-               IF SCAN THEN
-         UNTIL .PROMPT-CUR  .PROMPT  HCKEY  THEN ;
-
-
-
-Screen 8 not modified
-\ HELP-6                                       10:22JWB12/01/85
-: CHOOSE
-   BEGIN FKEY  IF DUP 13 <> ELSE TRUE THEN
-   WHILE CASE
-    72 OF MAXPROMPT 3 - +.PROMPT ENDOF   \ Up arrow
-    73 OF MAXPROMPT 9 - +.PROMPT ENDOF   \ Pg up
-    71 OF             .HPROMPT   ENDOF   \ Home key
-    79 OF             .EPROMPT   ENDOF   \ End  key
-    75 OF MAXPROMPT 1-  +.PROMPT ENDOF   \ Left arrow
-   115 OF     .FPROMPT   ENDOF           \ Control left arrow
-    77 OF  1 +.PROMPT    ENDOF           \ Right arrow
-   116 OF     .LPROMPT   ENDOF           \ Control right arrow
-    80 OF  3 +.PROMPT    ENDOF           \ Down arrow
-    81 OF  9 +.PROMPT    ENDOF           \ Pg down
-         ENDCASE REPEAT DROP ;
-
-Screen 9 not modified
-\ HELP-7                                       11:45JWB03/25/86
-: (HELP)   ( scr  nmax   -- )
-         MAXP ! HBLOCK !    FINI OFF
-         IPROMPT #PROMPT ! MENU
-         BEGIN   MENU   CHOOSE #PROMPT @
-                 IF .HELP  THEN
-                 FINI @ #PROMPT @ 0= OR
-         UNTIL   0 22 AT
-         #PROMPT @ IS IPROMPT  ;
-ONLY FORTH ALSO DOS ALSO HIDDEN ALSO FORTH DEFINITIONS
-: HELP  ( --  -- )
-         SCR @  FILE @ FLUSH
-   ( B: )  HELP.BLK  OPEN-FILE
-         [ BLK @ 1+ ] LITERAL   63  (HELP)
-         !FILES  OPEN-FILE SCR ! ;
-ONLY FORTH ALSO DEFINITIONS
-Screen 10 not modified
-EXIT HELP                       SCREEN VIEWING
-PRINTER AND WORD VIEWING        NO. DISPLAYING WORDS
-COLD FORGET  EMPTY BYE          HEX AND DECIMAL
-CONDITIONALS                    MORE CONDITIONALS
-SCREEN EDITING                  STAR-SLASH THE SCALAR
-INFINITE LOOPS                  INDEFINITE LOOPS
-ANOTHER LOOP                    LEAVING LOOPS EARLY
-BASIC STACK OPERATORS           FURTHER STACK OPERATORS
-RETURN STACK                    VIRTUAL MEMORY
-BLOCK AND UPDATE                MEMORY OPERATORS
-MORE MEMORY OPERATORS           WORD DEFINITION STRUCTURE
-VOCABULARY:ROOT:ONLY            DIVISION
-STRINGS                         STRING:COUNT:TYPE:EXPECT
-MOVING STRINGS                  BUFFER
-HIDE:REVEAL:IMMEDIATE           NUMBER FORMATING
-CASE STATEMENT                  VARIABLES AND CONSTANTS
-Screen 11 not modified
-MORE VARIABLES & CONST.         MULTITASKING
-TASK USER VARIABLES   .         PAUSE  RESTART
-SLEEP WAKE STOP                 MULTI SINGLE
-X                               X
-X                               X
-XMETA COMPILER                  X
-X                               X
-XDEMOS                          X
-XCRASH RECOVERY                 X
-X8086 CPU REGISTERS             X
-LEAVING FORTH                   STARTING FORTH P 50- 83
-STARTING FORTH P110-112         STARTING FORTH P119-135
-STARTING FORTH P137-143         STARTING FORTH P161-174
-STARTING FORTH P177-247         X
-X                               X
-X                               X
-Screen 12 not modified
-Screen Viewing Help
-
-L               Lists current screen
-B L             Lists previous screen
-N L             Lists next screen
-A L             Lists the shadow screen
-
-n LIST          Lists screen n
-n BROWSE        Use editor to browse screens
-
-n1 n2 INDEX     Lists the first line of screens n1 thru n2
-
-VIEW {word}     Browse the source definition for {word}
-
-
-
-Screen 13 not modified
-Printer and word viewing help
-
-PRINTING ON             Send output to printer, make sure its on
-PRINTING OFF            Send output to screen only
-
-WORDS                   List words in the context vocabulary.
-
-ONLY FORTH WORDS        Lists all words in FORTH
-
-ONLY EDITOR WORDS       Lists all words in EDITOR
-
-
-
-
-
-
-Screen 14 not modified
-NUMBER DISPLAYING WORDS
-    Single signed 16bit numbers      -32768  - 32767
-    .    ( n   -- )    Display signed 16bit # followed by space.
-    .R   ( n w  -- )   Display # right justified in w wide field.
-
-Single unsigned 16bit numbers.      0  - 65535
-    U.   ( u  -- )     Display unsigned 16bit # followed by space
-    U.R  ( u w   -- )  Display # right justified in w wide field
-
-Double signed 32bit numbers   -2,147,483,648  - 2,147,483,647
-    D.   ( d  -- )     Display signed 32bit # followed by a space
-    D.R  ( d w   -- )  Display # right justified in w wide field
-
-Double unsigned 32bit numbers.      0  - 4,294,967,296
-    UD.   ( ud  -- )   Display unsigned 32bit # followed by space
-    UD.R  ( ud w  -- ) Display # right justified in w wide field
-Screen 15 not modified
-\COLD FORGET  EMPTY  BYE
-
-
-
-
-    FORGET <name>   Remove <name> and all following words
-                    from the dictionary.
-
-
-    EMPTY           Remove all new words added since this
-                    session started
-
-
-    BYE             Exit Forth and return to DOS
-
-
-Screen 16 not modified
-HEX AND DECIMAL
-
-
-         HEX     ( --   -- ) Set the system number BASE to 16
-
-         DECIMAL ( --   -- ) Set the system number BASE to 10
-
-         You could also add the following words to your system.
-
-: OCTAL ( --  -- )  \ Set system number base to 8.
-         8 BASE ! ;
-
-: BINARY ( --  -- )  \ Set system number base to 2.
-         2 BASE ! ;
-
-
-Screen 17 not modified
-CONDITIONALS
-         tf = 1111111111111111  binary or base 2
-         ff = 0000000000000000  binary or base 2
-     TRUE   ( --   tf )    Leave true flag on top of the stack
-     FALSE  ( --   ff )    Leave false flag on top of the stack
-    =    ( n m  flag )     Leave tf if n = m , otherwise ff
-    <>   ( n m  flag )     Leave tf if n<> m , otherwise ff
-    <    ( n m  flag )     Leave tf if n < m , otherwise ff
-    >    ( n m  flag )     Leave tf if n > m , otherwise ff
-
-    0=   ( n    flag )     Leave tf if n = 0 , otherwise ff
-    0<>  ( n    flag )     Leave tf if n<> 0 , otherwise ff
-    0 <  ( n    flag )     Leave tf if n < 0 , otherwise ff
-    0 >  ( n    flag )     Leave tf if n > 0 , otherwise ff
-    ?DUP ( n    n (n))     Duplicate n if n is non zero
-    NOTE IF TRIGGERS ON ZERO
-Screen 18 not modified
-MORE CONDITIONALS
-                 NOTE THESE OPERATORS WORK AT THE BINARY LEVEL
-
-    AND  ( f1 f2   flag ) Leave tf only if f1 and f2 are true
-
-    OR   ( f1 f2   flag ) Leave tf if either f1 or f2 are true
-
-    XOR  ( f1 f2   flag ) Leave tf if f1=tf or f2=tf but not both
-
-    NOT  ( f1  not-flag ) Reverse the flag f1
-NOTE : Starting FORTH  NOT is the same as F83  0=
-        Starting FORTH  NOT is different than F83 NOT
-        F83 NOT operates on each of a numbers 16 bits
-        F83 NOT leaves a false flag ( zero ) only if it
-        operates on a true flag -1111111111111111 binary
-        F83 NOT is not the same as 0=
-Screen 19 not modified
-SCREEN EDITING
-
-        FILE?      Display current screen file
-        DEFAULT    Revert to default screen file
-                   used when FORTH was started
-
-        OPEN <name>.BLK   Open an existing screen file
-
-        CREATE-FILE <name>.BLK  ( n )
-                   Create a new screen file <name>.BLK
-                   with  n  blank screens
-         MORE      Add  n  blank screens to the end of
-                   the current screen file
-         CAPACITY  Leave number of screens in the current
-                   screen file
-
-Screen 20 not modified
-STAR-SLASH THE SCALAR
-
-     */   ( a b c   ab/c )  Perform multiplication and then
-     division. Star-slash multiplies 16bit a  and  b  to form
-     a 32bit intermediate result which is then divided by 16bit
-     c  to give a 16bit result. The 32bit intermediate product
-     ensures accurate results when multipying by fractions.
-
-
-
-
-
-
-
-
-
-Screen 21 not modified
-INFINITE LOOPS
-
-         The infinite loop with no exit. This is recommended
-         only for an end user application.
-
-           ... (step 1)   BEGIN   (step 2)  AGAIN  (step 3) ...
-
-         step 1 is executed once; step 2 is repeated forever.
-         Note: step 3 is never executed.
-
-
-
-
-
-
-
-Screen 22 not modified
-INDEFINITE LOOPS
-
-         In the indefinite loop the main action is repeated
-         until a condition is true. Step 1 is executed once,
-         step 2 is executed and (condition) is tested. If
-         condition is false step 2 is executed again, if
-         condition is true then step 3 is executed. Note
-         that step 3 following the loop will be executed
-         when loop is exited .
-
-
-               ... (step 1)   BEGIN   (step 2)
-                                      (condition)
-                              UNTIL   (step 3)   ...
-
-
-Screen 23 not modified
-ANOTHER LOOP
-
-         Indefinite loop - another form
-         In this form step 1 is executed once. Step 2 is
-         executed if condition is true do step 3 and repeat
-         starting with step 2 if condition is false leave loop
-         and do step 4.
-
-         ... (step 1)   BEGIN   (step 2)
-                                (condition)
-                        WHILE   (step 3)
-                        REPEAT  (step 4)  ...
-
-
-
-
-Screen 24 not modified
-LEAVING LOOPS EARLY
-Execute step 1. Repeat loop executing step 2 and step 4 on each
-pass - except that if condition is true before loop is finished
-execute step 3 and leave loop to execute step 5. Note step 4
-will not be executedif we leave the loop early.
-
-    ...     (step 1)   DO     (step 2)
-                              (condition) IF (step 3) LEAVE THEN
-                              (step 4)
-                       LOOP   (step 5)   ...
-This is an alternative form if step 3 is not required.
-    ...     (step 1)   DO     (step 2)
-                              (condition)  ?LEAVE
-                              (step 4)
-                       LOOP   (step 5)   ...
-NOTE:EXIT CANNOT BE USED IN DO LOOPS -IT RUINS THE RETURN STACK
-Screen 25 not modified
-BASIC STACK OPERATORS
-    DROP  ( n   -- )      Drop top number on data stack
-    SWAP  ( n m   m n )   Swap top two numbers on data stack
-    DUP   ( n  n n )      Duplicate top number on data stack
-    OVER  ( n m   n m n ) Make copy of second item to top of
-    ROT   ( a b c b c a ) Rotate third item to the top of stack
-   -ROT   ( a b c c a b ) Rotate in opposite direction
-    PICK  ( ? n  ? nth  ) Copy nth item to top of stack (0 based)
-    ROLL  ( ? n  ? nth  ) Rotate nth item to top (0 based)
-    NIP   ( n m   m )     Discard second item on data stack
-    TUCK  ( n m   m n m ) Push copy of top under second item
-    3DUP  ( a b c  a b c a b c )   Make a copy of the top 3 items
-    2DROP ( dn   -- )     Drop double number from the top
-    2SWAP ( dn dm   dm dn ) Swap the top two double numbers
-    2DUP  ( dn   dn dn )  Make another copy of top double number
-    2OVER ( dn dm   dn dm dn ) Copy second double number to top
-Screen 26 not modified
-FURTHER STACK OPERATORS
-         1+      Increment top stack item by
-
-         2+      Increment top stack iten by 2
-
-         1-      Decrement top stack item by 1
-
-         2-      Decrement top stack item by 2
-
-         2*      Multiply  top stack item by 2
-
-         2/      Divide    top stack item by 2
-
-         ABS     Replace top item by its absolute value
-
-         NEGATE  Negate top stack item
-Screen 27 not modified
-RETURN STACK
-  >R  R> and  R@ are for accessing the return stack.These words
-are very dangerous!!. Do NOT test or execut them interactively.
-They can only be used within colon definitions.
-   Note: D) indicates data stack,  R) indicates return stack.
-Transfer top data stack item to return stack.
-         >R   ( n   -- D )   ( --   n R )
-Transfer top return stack item to data stack.
-         R>   ( --   n D )   ( n   -- R )
-Copy top return stack item to data stack.
-         R@   ( --   n D )   ( n    n R )
-
-RULES:
-  1. Each use of >R must be balanced with a corresponding R>.
-  2. Do not use >R R> and R@ within DO ... LOOPS. Loop control
-     info is kept on the return stack and could be destroyed.
-Screen 28 not modified
-VIRTUAL MEMORY
-F83 virtual memory operates as follows:
-The current file open on the mass storage is divided into
-consecutive blocks. The block is the basic unit of storage.
-Each block holds 1024 bytes. Blocks are numbered consecutively
-starting with block 0 at the beggining of the file. On the mass
-storage device (disk or hard disk) the only limit to the number
-of blocks in a file is the capacity of the mass storage device.
-
-In the ram memory of the computer there is an area reserved for
-disk buffers. One disk buffer will hold 1024 bytes. In F83 there
-are 4 disk buffers. Thus in the computers ram memory there can
-only be 4 blocks at any one time. FORTH's virtual memory system
-keeps track of which blocks are in ram memory and which blocks
-are on the mass storage device. This housekeeping is transparent
-to the user.
-Screen 29 not modified
-BLOCK AND UPDATE
-
-
-BLOCK  ( n   adr )  Given the block number n, BLOCK returns
-        the address, adr, of the assigned block buffer. The
-        buffer address, adr, is the loaction of the first data
-        storage cell of the buffer, which consists if 1024 bytes.
-
-
-UPDATE ( --   -- )  Mark most recently referenced block as
-        modified. Then if it's block buffer is required it will
-        automatically be transfered back to mass storage.
-
-
-
-
-Screen 30 not modified
-MEMORY OPERATORS
-   DUMP  ( adr n   -- ) Dump n bytes of memory starting at adr.
-   ERASE ( adr n   -- ) Erase n bytes of memory starting at
-                        adr to zeros.
-   FILL ( adr n m  -- ) Fill n bytes of memory starting at adr
-                        with low 8 bits of m  ( 0 - 255 ).
-
-   !    ( n adr   -- )  STORE 16 bit value at address adr.
-   @    ( adr     n  )  FETCH 16 bit value at adr and leave as n.
-
-NOTE: 16 BIT NUMBERS ARE STORED WITH THE LOW BYTE AT adr AND THE
-       HIGH BYTE AT adr+1 ( THIS IS THE CONVENTION FOR 6502 AND
-       8086 CPUs - THE 68000 IS NORMAL ).
-   C!   ( n adr   -- )  Store low 8 bits of n at address adr.
-   C@   ( adr     n  )  Fetch 8 bit value at adr and leave as n.
-   ?    ( adr     -- )  Display contents of cell at adr.
-Screen 31 not modified
-MORE MEMORY OPERATORS
-        NOTE : cell = 2 bytes = 16 bits = 1 word
-    +!   ( n adr  -- ) Add n to the value found at address adr.
-    ON   ( adr    -- ) Set cell at adr to true or -1
-    OFF  ( adr    -- ) Set cell at adr to false or 0
-
-CREATE (name) (-- --) Creates a dictionary entry named <named>
-                       when executed,<name> leaves the address
-<name>  ( --    adr ) of the first memory cell which follows
-                       the word name. No memory is allocated.
-ALLOT   ( n      -- ) Allocate n bytes of memory in the
-                       dictionary.
-    ,    ( n      -- ) Allocate 16 bits ( 2 bytes ) of memory
-                       initializing it to the value n.
-   C,    ( n      -- ) Allocate 8 bits ( 1 byte ) of memory
-                       initializing it to low 8 bits of n.
-Screen 32 not modified
-WORD DEFINITION STRUCTURE
-
-
-              | 4bits   |  12 bits     |
-    vfa   ->  | File #  |  Block #     |   View Field
-    lfa   ->  | Link address           |   Link Field
-    nfa   ->               | 1PScount  |   Name Field count=5bits
-                           | 0 char    |
-                           | 0 char    |   char = 7bits
-                           | 0 char    |
-                           | 1 char    |
-    cfa   ->  | Addr Inner Interpr.    |   Code field
-    pfa   ->  | Parameter List         |   Parameter Field
-              |    .  .   .  .         |   Also called the
-              |    .  .   .  .         |   BODY of the word
-              |    .  .   .  .         |   definition
-Screen 33 not modified
-VOCABULARY:ROOT:ONLY
-
-   VOCABULARY  {name}  ( --   -- )
-   A dictionary entery for  {name}  is created which specifies a
-   new list of word definitions. Subsequent execution of  {name}
-   replaces the first vocabulary in the current search order with
-   {name} . When name becomes the compilation vocabulary new
-   definitions will be appended to  {names}'s word list.
-
-   ROOT  ( --   -- )
-   A small vocabulary for controlling search order.
-
-   ONLY  ( --   -- )
-   Erases the search order and forces the ROOT vocabulary to be
-   first and last.
-
-Screen 34 not modified
-DIVISION
-
-              Floored symetric division
-
-              Note that q and r must satisfy the equation.
-
-                        m/n = q + r/n
-
-                or      m = nq + r
-
-         /   ( m n   q )  Leave q  ,the floor of real quotient
-
-         MOD ( m n   r )  Leave r  ,remainder (satisfying above)
-
-         /MOD (m n   r q ) Leave remainder r and quotient q
-
-Screen 35 not modified
-STRINGS
-A counted string in memory is    |05|48|45|4C|4C|4F|  <-hex-<
-preceded by character count.     |05| H| E| L| L| O|
-
-," {text}"  ( --   -- )  ONLY USE OUTSIDE A WORD DEFINITION
-Compile a counted {text} string into dictionary. Do not use in
-a word definition!!  SYSTEM WILL CRASH.
-
-" {text}" ( --   adr count )  ONLY USE WITHIN A WORD DEFINITION
-Compile a counted string into a word definition. When word is
-later executed the address and count are returned.
-
-Examples:
-CREATE NAME$ ," GEORGE SMITH"
-: JOB$  " FORTH Progammer" ;
-                     ^
-Screen 36 not modified
-STRING COUNT TYPE EXPECT
-COUNT  ( adr   adr+1 n )
-      If adr points to a counted string, COUNT will fetch the
-      character count an increment adr to point to first
-      character. Count is often used to fetch succesive
-      characters of a string.
-
-TYPE   ( adr n  -- )  Type n characters of a string at adr.
-
-FILL   ( adr   n c )  Fill string at adr with n copies of c.
-
-ERASE  ( adr  n )     Fill string at adr with n null's or 0's
-
-EXPECT ( adr  n )  Input a string of length n  to beffer at adr.
-Actual number of characters entered is stored in a variable
-called SPAN .NOTE: EXPECT does not return a counted string.
-Screen 37 not modified
-MOVING STRINGS
-
-    CMOVE    ( adrf adrt   n -- )      Use when adrf > adrt
-Move n bytes from adrf to adrt. Left-most or low memory bytes
-are moved first. ( ie Move starts at begginning of string. )
-Use  CMOVE  to move strings down to lower memory.
-
-    CMOVE>   ( adrf adrt   n -- )      Use when adrf < adrt
-Move n bytes from adrf to adrt. Right-most or high memory bytes
-are moved first. ( ie Move starts at end of string. )
-Use  CMOVE> to move strings up to a higher memory.
-
-    MOVE     ( adrf adrt   n -- )
-Move n bytes from adrf to adrt. If adrf < adrt use CMOVE>
-otherwise use CMOVE. this will prevent overlap.
-Use MOVE when you can't remember wether to use CMOVE or CMOVE>.
-Screen 38 not modified
-BUFFER
-BUFFER  ( n  adr ) Assign block n the buffer storage area at
-       adr . The function is the same as for BLOCK except
-       that the contents of the data storage area are undefined
-       That is . . . The buffer is assigned only and if the
-       block is not already in memory its contents might not be
-       transferred from mass storage. Not often used.
-
-EMPTY-BUFFERS ( --   -- ) Erase all data in block buffers,
-       initialize buffer pointers and mark buffers as empty.
-
-SAVE-BUFFERS  ( --   -- ) Transfer all buffers marked as
-       updated to mass storage and then mark them as unmodified.
-
-FLUSH         ( --   -- ) Same effect as SAVE-BUFFERS followed
-       by EMPTY-BUFFERS
-Screen 39 not modified
-HIDE:REVEAL:IMMEDIATE
-
-HIDE        Unlink most latest word from dictionary.
-
-REVEAL      Link the latest word inti the dictionary.
-
-IMMEDIATE   Set precedence bit so latest word is executed
-             during compilation instead of being compiled.
-
-['] {word}  This is an IMMEDIATE word used within a definition
-             It is used to compile the cfa of the following word
-             as a LITERAL or number. It is equivalent to the
-             sequence
-
-[ ' {word} ] LITERAL
-
-Screen 40 not modified
-NUMBER FORMATING
-
-PAD  ( --   adr )  Return address for string output buffer.
-HLD  ( --   adr )  Pointer to current loacation in output buffer
-HOLD ( --   adr )  Add character n to string being formed.
-SIGN ( n    --  )  If n is negative insert a -ve sign in the
-                    output string. This is different from BRODIE.
-
-  <#  ( dn   dn  )  Start number formating  ( pad hld ! )
-                    dn, the number to be formated , is not used
-                    <# but is usually present.
-  #   ( dn   dn' )  Convert one digit of dn using current number
-                    BASE and remaining digits as dn' .
-  #S  ( dn   dn' )  Convert a number until finished. When
-                    conversion is finished dn' will be zero.
-  #>  ( dn   adr len )  Terminate numeric conversion.
-Screen 41 not modified
-CASE STATEMENT
-CASE ... OF ... ENDOF ... ENDCASE
-CASE     causes an index value to be compared to a series
-OF       values. Any number of OF .. ENDOF pairs may be used.
-OF       is equivalent to OVER = IF DROP
-ENDOF    is equivalent to else
-ENDCASE  is equivalent to DROP and number of THENs
-When the index value equals one of the OF values,the sequence
-between that OF and the corresponding ENDOF is executed.
-Control then branches to the word following ENDCASE.
-If no match is found, ENDCASE drops the index from the stack.
-
-The "otherwise" case may be handled by a sequence placed between
-the last ENDOF and ENDCASE. The index value must however be
-preserved across this otherwise sequence so that ENDCASE may
-DROP it.
-Screen 42 not modified
-VARIABLES AND CONSTANTS
-Values which change quite frequently and must be accessed by a
-number of words are best represented by the use of  VARIABLES.
-Values represented by variables have the added convenience of
-reference by name.
-
-      VARIABLE <name> (--  -- )   Create 16bit data storage
-                                  called <name>
-      <name>          (--  adr )  Leave storage address of <name>
-
-Values which never change are best represented by CONSTANTs
-
-      CONSTANT <name> ( n  -- )   Create a constant  <name>
-                                  whose value is  n.
-      <name>          ( --  n )   Leave value of <name> on stack
-
-Screen 43 not modified
-MORE VARIABLES AND CONSTANTS
-
-   2VARIABLE <name>      Creates a 2 cell ( 4 byte ) variable
-                         called <name>.
-
-   <name>   ( --   adr ) When <name> is executed it will push
-                         the address of the first cell onto the
-                         stack.
-
-   2CONSTANT <name>      Creates a double constant called <name>
-             ( --    d ) When <name> is executed the double
-                         number is pushed onto the data stack.
-
-   2!      ( d adr  -- ) Store the double number d at adr.
-
-   2@      ( adr     d ) Fetch the double number d from adr.
-Screen 44 not modified
-MULTITASKING
-Multitasking allows one computer to appear to do several things
-at the same time. Most of the time a single user computer sits
-in an idle loop waiting for the operator to press the keyboard.
-
-The idea is to utilize this waiting time to perform other useful
-tasks. Typical background tasks would be watching over
-instruments in the lab,printing a long file,updating a clock etc
-
-F83 uses a very simple yet effective round-robin scheduling
-technique. Task switching is extremely fast because each task
-maintains its own parameter and return stacks and its own set
-of critical variables (called USER variables ) .
-
-The task switcher just changes the pointer to the correct list
-of USER variables.
-Screen 45 not modified
-TASK DEPENDENT USER VARIABLES
-The following USER variables are needed in every task.
-TOS       Saved during Task switching.
-ENTRY     Jumped to during multitasking.
-LINK      Points to next task in the circular queue.
-SP0       Empty parameter stack for this task.
-RPO       Empty return stack for this task.
-DP        Size of dictionary. Next available location.
-#OUT      Number of characters sent since last CR.
-#LINE     Number of CR's sent since last page.
-OFFSET    Added to all block references.
-BASE      The current numeric base for number input output.
-HLD       Points to a converted character during numeric output.
-FILE      Allows printing of one file while editing another.
-IN-FILE   Allows printing of one file while editing another.
-PRINTING  Indicates wether printing is enabled.
-Screen 46 not modified
-PAUSE RESTART
-
-PAUSE   When multitasking PAUSE stops the current task and
-         passes control to the next task in the round robin.
-
-         When singletasking PAUSE is equivalent to a NOOP.
-
-RESTART When multitasking RESTART does the reverse of PAUSE.
-         It restores critical information stored in task user
-         variables and starts executing the task left asleep
-         during the last pass.
-
-
-
-
-
-Screen 47 not modified
-SLEEP WAKE STOP
-
-
-SLEEP  ( adr   -- ) Used in the form:   {taskname} SLEEP
-        Make the addressed task pause indefinitely.
-
-WAKE   ( adr   -- ) Used in the form:   {taskname} WAKE
-        Wake up task so that it will execute the next time round.
-
-STOP   ( --    -- ) Make the current task pause indefinitely.
-
-
-
-
-
-
-Screen 48 not modified
-MULTI SINGLE
-
-
-MULTI   Start the multitasker. This is done by installing the
-         the sheduler/dispatcher loop and activating PAUSE.
-
-SINGLE  Stop multitasking. This is done by removing the
-         sheduler/dispatcher loop and restoring PAUSE to
-         its NOOP function.
-
-
-
-
-
-
-
-Screen 53 not modified
-\ Hard copy screen documentation.              11:23JWB11/23/85
-
-\ Print three screens starting with n on the printer.
-: HTRIAD  ( n   -- )
-         PRINTING ON                DUP 3 +  SWAP
-       ( 27 EMIT ASCII E EMIT  ) CONTROL N EMIT
-         DO CR I LIST LOOP  ( 27 EMIT ASCII F EMIT )
-         CONTROL O EMIT  PRINTING OFF ;
-
-\ Send a top of page command to printer.
-: FFEED
-         PRINTING ON 12 EMIT PRINTING OFF ;
-
-\ Print screens  first through last  on printer, three per page.
-: DOC   ( first last   -- )
-         1+ SWAP DO I HTRIAD FFEED 3 +LOOP ;
-Screen 64 not modified
-\ Notes on Starting Forth. 1                   14:09JWB01/09/86
-\ P 50    Replace 'S with SP@ or define  : 'S   SP@ ;
-\         Replace S0 with SP0 or define  : S0   SP0 ;
-\  Because FORTH83 loops work differently you should use:
-         : .S CR  SP@ SP0 @ 2DUP <>
-              IF   2- DO I  @ . -2 +LOOP
-              ELSE 2DROP ." EMPTY" THEN   ;
-\ Or  just use .S  that is already part of your system.
-
-\ P 66-72  Use:    n  VEDIT     to edit screen n .
-\ The original F83.COM fill supports the STARTING FORTH style
-\ editor.   Go back to DOS and type  F83  <name>.BLK  to try it.
-\ P 83  See notes for P 50 above.  Also VIEW  .S  to see how
-\        the F83 version is implemented.
-
-
-Screen 65 not modified
-\ Notes on Starting Forth. 2                   17:12JWB09/22/85
-\ P 110 In F83 I J and K are used only within loops to fetch
-\       the current values of the loop counters.  Use  R@
-\       instead of I to fetch a copy of the top of the return
-\       stack to the parameter stack without changing the
-\       return stack.
-\       Use the sequence:  R> R@ SWAP >R  within a definition
-\       instead of I' to fetch  a copy of the second item on
-\       the return stack.  Or use the definition:
-: 2R@   R> R> R@ -ROT >R >R ;
-\       Use 2R@  for I' .   I' is a poor name!!
-\       WARNING!  It is dangerous to mess with the return stack.
-\ P112  Use  R@  instead of I  ,  also a dot  .  was ommited
-\       from the definition of QUADRATIC.   See below.
-: QUADRATIC     ( a b c x   n )
-         >R SWAP ROT R@ * + R> * + .  ;
-Screen 66 not modified
-\ Notes on Starting Forth. 3                   17:13JWB09/22/85
-\ P 119 Error in footnote!
-: R%  50 */ 1+ 2/ ;
-\ P 123 I I' and J  see comments for page 110.
-\ P 131 For COMPOUND to display as in text  insert a   CR
-\       before  SWAP .  ie  : COMPOUND  CR SWAP 21 0 DO  etc
-\ P 135 There is an error in TEST -  should be 10 10 DO  but
-\       even so . .   the FORTH83  DO .. LOOP is not like
-\       the one in Starting FORTH !!!!   Try the following
-: -TEST  DO I . ?KEY ?LEAVE ( any key exit ) -1 +LOOP ;
-: +TEST  DO I . ?KEY ?LEAVE ( any key exit )  1 +LOOP ;
-\  9 10 +TEST   loops 65534 times.  9 10 -TEST gives   10 9
-\ 10 10 +TEST   loops 65535 times. 10 10 -TEST gives   10
-\ 11 10 +TEST  gives  10           11 10 -TEST loops 65535 times
-\ If you try any of the longer loops above press any key to
-\ abort!!
-Screen 67 not modified
-\ Notes on Starting Forth. 4                   17:13JWB09/22/85
-\ P 137 XX will clear the stack as indicated but our definition
-\       : CLEAR  DEPTH 0 ?DO DROP LOOP ;  will do it without
-\       the error message.  An alternate definition of CLEAR is:
-: CLEAR  SP0 @ SP! ;
-\ P 140 In FORTH83  LEAVE causes an immediate exit from the
-\       DO ... LOOP  !!  Thus any words between LEAVE and LOOP
-\       will not be executed if the condition for leaving is
-\       is satisfied.  Try the following and note that  HELLO
-\       is not printed the last time.
-: HELLOS  10 1 DO CR I . I 5 = IF LEAVE THEN ." HELLO" LOOP ;
-\       Note: ?LEAVE can replace the phrase  IF LEAVE THEN
-\ P 142-143  Use CLEAR-SCREEN definition below instead of PAGE
-: CLEAR-SCREEN  0 0 0 2 [ EDITOR ] VIDEO-IO 2DROP 2DROP ; FORTH
-
-
-Screen 68 not modified
-\ Notes on Starting Forth. 5                   17:13JWB09/22/85
-\ P 161 In FORTH83  UM*     is the name for U*
-\       and         UM/MOD  is the name for U/MOD
-\       In FORTH83  all loops are relative, use +LOOP for /LOOP
-\ P 164 Double number punctuation is  .  only!  not  ,
-\ P 166 Use the   .   for the  ,  in the double numbers!!!
-\ P 169 FORTH83   SIGN  uses the first number on the stack!!
-\       Whenever Brodie uses  SIGN  replace it with  ROT SIGN
-\ P 170 Replace   SIGN   with   ROT  SIGN
-\       VIEW  D.  to see how F83  formats numbers.
-\ P 172 Replace   SIGN   with   ROT  SIGN
-\ P 174 Use the definitions below:
-: M+    S>D D+ ;     : M/    M/MOD  NIP ;
-: M*/   2DUP XOR SWAP ABS >R SWAP ABS >R OVER XOR -ROT
-         DABS SWAP R@ UM* ROT R> UM* ROT 0 D+ R@ UM/MOD
-         -ROT R> UM/MOD NIP SWAP ROT ?DNEGATE ;
-Screen 69 not modified
-\ Notes on Starting Forth. 6                   17:28JWB09/22/85
-\ P 177 In FORTH83  use   UM*  for  U* and UM/MOD for U/MOD
-\       In FORTH83  use  +LOOP for /LOOP
-\ P 178 Use  ROT SIGN where ever Brodie uses SIGN  !!
-\ P 202 Use CLEAR-SCREEN definition given earlier for  PAGE
-\ P 204 Use +LOOP  for /LOOP
-\ P 215 Type  VIEW  INTERPRET  for definition of our INTERPRET
-\ P 217 In F83  DEFER   is used for execution vectors.
-\ P 233 In F83  the variable H is called  DP
-\ P 235-237  : 'S  SP@ ;
-\ P 240 Use DP  instead of H  ;  No OFFSET in this system.
-\ P 242 F83 Uses the ONLY vocabulary structure. See the FORTH-83
-\       standard or wait till we discuss it in class.
-\ P 247 Use DP  instead of H  .
-
-
-</code>