Tag: retrocomputing

  • Word Processors in BASIC, Part 2

    Word Processors in BASIC, Part 2

    Nibblewriter

    Found in November 1988 issue of Nibble magazine.

    Archive.org link here.

    The project was alerted to the existence of a few text editors and word processors in Nibble magazine by someone on matrix.

    What we found was a great wealth of BASIC programs for the Apple II computer. We uncovered several particularly interesting BASIC word processors. Two that are of particular interest are Quickwriter and this one, Nibblewriter.

    diskM8 File Dump

    Please find an ASCII conversion of the BASIC dump obtained using the following commands:

    $ diskm8 -ingest /path/to/your/disk/images
    $ diskm8 -search "nibblewriter"
    $ diskm8 -with-disk "your_disk_image.do" -file-extract "NIBBLEWRITER.BAS"

    Code Listing

    10  REM *************************
    20  REM *     NIBBLEWRITER      *
    21  REM *     ------------      *
    30  REM *  BY ROBERT T. YUILLE  *
    40  REM *  COPYRIGHT (C) 1988   *
    50  REM *  BY MICROSPARC, INC.  *
    60  REM *  CONCORD, MA  01742   *
    70  REM *************************
    80  HOME : PRINT  CHR$ (21)
    90  REM   SET HIMEM
    100 PRODOS =  PEEK (48896) = 76: IF  NOT PRODOS THEN  HIMEM: 24832: GOTO 170
    110  REM   FOR PRODOS
    120  POKE 768,32: POKE 769,248: POKE 770,190
    130  POKE 771,169: POKE 772,53: POKE 773,32
    140  POKE 774,245: POKE 775,190: POKE 776,96
    150  CALL 768
    160  REM   INITIALIZATION
    170 LM$ = "1.0":RM$ = "1.0":TM$ = "1.0":BM$ = "1.0"
    180 LM = 8:RM = 66:TM = 6:BM = 60
    190  POKE 30,0: POKE 233,0: REM  NEWF & PRNTF
    200 D$ =  CHR$ (4):B$ =  CHR$ (7):E$ =  CHR$ (27):R$ =  CHR$ (13): IF  NOT PRODOS THEN D$ =  CHR$ (13) +  CHR$ (4)
    210 M1$ = "MARGIN VALUE EXCEEDS MAXIMUM"
    220 M2$ = "MARGIN VALUE IS LESS THAN MINIMUM"
    230 M3$ = "CHAR CANNOT BE USED IN THIS INPUT"
    240 FL$ = "WP.40.O"
    250 FADDR = 26124: REM   FILENAME ($660C)
    260 ST = 6:DR = 1: REM  DEFAULT SLOT AND DRIVE
    270  PRINT D$"PR#0"
    280 :
    290  REM   LOAD WP OBJECT FILE
    300 :
    310 LK = 1: ONERR  GOTO 3130
    320  PRINT D$"BLOAD NW.BIN"
    330  POKE 216,0: REM  RESET ERROR FLAG
    340 :
    350  REM    INITIALIZE & READ MENU DATA
    360 :
    370  READ MITEMS: DIM MENU$(9): FOR J = 0 TO MITEMS: READ MENU$(J): NEXT 
    380  DIM X$(1):X$(0) = "   ":X$(1) = "-->"
    390 :
    400  REM   MAIN MENU
    410 :
    420  TEXT : HOME : GOSUB 3040: POKE 216,0: ONERR  GOTO 3130
    430 PX = 38:SX = 4:SE = SE + (SE = 0):MX = MITEMS: GOSUB 2960: IF Z = 20 THEN  PRINT B$: GOTO 420
    440  ON SE GOTO 480,560,670,890,940,990,1480,2750,1740
    450 :
    460  REM   START NEW DOCUMENT
    470 :
    480  IF  PEEK (30) = 2 THEN  GOSUB 2660: IF ESCF = 1 THEN 420
    490  GOSUB 1830: IF ESCF = 1 THEN 420
    500  POKE 30,0
    510  CALL 26112: REM   ENTRY ($6600)
    520  GOTO 420
    530 :
    540  REM   LOAD NEW DOCUMENT
    550 :
    560  IF  PEEK (30) = 2 THEN  GOSUB 2660: IF ESCF = 1 THEN 420
    570  GOSUB 1830: IF ESCF = 1 THEN 420
    580  HTAB 1: VTAB 20: PRINT "LOADING "FL$
    590 LK = 3: ONERR  GOTO 3130
    600  PRINT D$"BLOAD "FL$",S"ST",D"DR
    610  POKE 216,0
    620  POKE 30,1: REM  SET NEWF FOR LOADED FILE
    630  GOTO 510
    640 :
    650  REM   SAVE CURRENT DOCUMENT
    660 :
    670  HOME : IF  PEEK (30) <  > 2 THEN  VTAB 5: PRINT "THERE IS NO CURRENT DOCUMENT": VTAB 10: PRINT "PRESS RETURN FOR MAIN MENU: ";: GET A$: GOTO 420
    680 EF =  PEEK (252) + 256 *  PEEK (253): REM  EFL($FC) & EFH($FD)
    690 LN = EF - 28672
    700  ONERR  GOTO 800
    710  PRINT D$"VERIFY "FL$",S"ST",D"DR
    720  HOME : VTAB 5: PRINT "FILE: '"FL$"' ALREADY EXISTS"
    730  VTAB 13: PRINT "PRESS 'Y' TO REPLACE EXISTING FILE": PRINT : PRINT "PRESS 'N' TO RENAME FILE": VTAB 10: PRINT "DO YOU WANT TO REPLACE": PRINT "THE EXISTING FILE? (Y/N) ";
    740  GET A$
    750  IF A$ = "N" OR A$ = "n" THEN  POKE 216,0: GOTO 840
    760  IF A$ <  > "Y" AND A$ <  > "y" THEN  GOTO 740
    770  HTAB 1: VTAB 20: PRINT "DELETING "FL$
    780 LK = 2: ONERR  GOTO 3130
    790  PRINT D$"DELETE "FL$",S"ST",D"DR
    800  HTAB 1: VTAB 21: PRINT "SAVING "FL$
    810 LK = 2: ONERR  GOTO 3130
    820  PRINT D$"BSAVE "FL$",A$7000,L"LN",S"ST",D"DR
    830  POKE 216,0: GOTO 420
    840  GOSUB 1830: IF ESCF = 1 THEN 420
    850  GOTO 670
    860 :
    870  REM   RENAME CURRENT DOCUMENT
    880 :
    890  GOSUB 1830: IF ESCF = 1 THEN 420
    900  GOTO 510
    910 :
    920  REM   CONTINUE WITH CURRENT DOCUMENT
    930 :
    940  IF  PEEK (30) <  > 2 THEN 670
    950  GOTO 510
    960 :
    970  REM   PRINTER ROUTINE
    980 :
    990  IF  PEEK (30) <  > 2 THEN 670
    1000  HOME : VTAB 2: PRINT "MARGIN VALUES ARE AS FOLLOWS:": PRINT : PRINT "LM= "LM$"  RM= "RM$"  TM= "TM$"  BM= "BM$
    1010  VTAB 10: PRINT "DO YOU WANT TO CHANGE MARGINS (Y/N)? ";
    1020  GET A$
    1030  IF A$ = "Y" OR A$ = "y" THEN 1060
    1040  IF A$ <  > "N" AND A$ <  > "n" THEN 1020
    1050  GOTO 1370
    1060 M$ = "LM":MA$ = "7.0":MI$ = "0.5"
    1070  GOSUB 2330: IF ESCF = 1 THEN 420
    1080 N =  VAL (N$)
    1090  IF N > 7 THEN MSG$ = M1$: GOSUB 2250: GOTO 1060
    1100  IF N < .5 THEN MSG$ = M2$: GOSUB 2250: GOTO 1060
    1110 LM = N * 10 - 2
    1120 LM$ = N$
    1130 M$ = "RM":MA$ = "7.0":MI$ = "0.5"
    1140  GOSUB 2330: IF ESCF = 1 THEN 420
    1150 N =  VAL (N$)
    1160  IF N > 7 THEN MSG$ = M1$: GOSUB 2250: GOTO 1130
    1170  IF N < .5 THEN MSG$ = M2$: GOSUB 2250: GOTO 1130
    1180 RM = 80 - (N * 10 - 4) - LM
    1190  IF RM <  = 0 THEN MSG$ = "LEFT MARGIN EXCEEDS RIGHT MARGIN": GOSUB 2250:RM = 66: GOTO 990
    1200 RM$ = N$
    1210 M$ = "TM":MA$ = "8.0":MI$ = "0.2"
    1220  GOSUB 2330: IF ESCF = 1 THEN 420
    1230 N =  VAL (N$)
    1240  IF N > 8 THEN MSG$ = M1$: GOSUB 2250: GOTO 1210
    1250  IF N < .2 THEN MSG$ = M2$: GOSUB 2250: GOTO 1210
    1260 TM =  INT (6 * N + .5)
    1270 TM$ = N$
    1280 M$ = "BM":MA$ = "8.0":MI$ = "0.2"
    1290  GOSUB 2330: IF ESCF = 1 THEN 420
    1300 N =  VAL (N$)
    1310  IF N > 8 THEN MSG$ = M1$: GOSUB 2250: GOTO 1280
    1320  IF N < .2 THEN MSG$ = M2$: GOSUB 2250: GOTO 1280
    1330 BM = 66 -  INT (6 * N + .5)
    1340  IF TM >  = BM THEN MSG$ = "TOP MARGIN EXCEEDS BOTTOM MARGIN": GOSUB 2250: GOTO 1210
    1350 BM$ = N$
    1360  GOTO 990
    1370  POKE 26,TM: POKE 27,BM: POKE 28,LM: POKE 29,RM
    1380  HOME : VTAB 2: PRINT "BE SURE YOUR PRINTER IS READY": VTAB 10: PRINT "PRESS RETURN TO CONTINUE: ";: GET A$
    1390  HOME : VTAB 15: PRINT "PRESS ESCAPE TO CANCEL PRINTING."
    1400  VTAB 10: PRINT "PRESS SPACE BAR TO CONTINUE: "
    1410  PRINT D$"PR#1"
    1420  PRINT  CHR$ (9)"80N": POKE 233,1: CALL 26112: POKE 233,0
    1430  PRINT D$"PR#0"
    1440  GOTO 420
    1450 :
    1460  REM   HELP SCREEN
    1470 :
    1480  TEXT : HOME 
    1490  NORMAL : PRINT "             HELP SCREEN": REM  13 SPACES
    1500  PRINT : PRINT 
    1510  PRINT "<ARROWS> - MOVE CURSOR"
    1520  PRINT 
    1530  PRINT "<ESCAPE> - RETURN TO MAIN MENU"
    1540  PRINT 
    1550  PRINT "<DELETE> - DELETE CHAR LEFT OF CURSOR"
    1560  PRINT 
    1570  PRINT "<CTRL>-D - DELETE CHAR UNDER CURSOR"
    1580  PRINT 
    1590  PRINT "<CTRL>-E - CHANGE INSERT/REPLACE CURSOR"
    1600  PRINT 
    1610  PRINT "<CTRL>-Y - CLEAR FROM CURSOR TO EOL"
    1620  PRINT 
    1630  PRINT "<CTRL>-Z - SHOW CR'S AS INV ASTERISK"
    1640  PRINT 
    1650  PRINT "   <TAB> - MOVE CURSOR TO NEXT TAB POS"
    1660  PRINT 
    1670  PRINT "<CTRL>-F - MOVE TO FIRST LINE"
    1680  PRINT "<CTRL>-C - MOVE TO CENTER LINE"
    1690  PRINT "<CTRL>-L - MOVE TO LAST LINE";
    1700  HTAB 1: VTAB 24: PRINT "PRESS RETURN TO CONTINUE: ";: GET A$: GOTO 420
    1710 :
    1720  REM   QUIT
    1730 :
    1740  HOME : VTAB 10: PRINT "DO YOU REALLY WANT TO QUIT (Y/N)? ";
    1750  GET A$
    1760  IF A$ = "Y" OR A$ = "y" THEN 1790
    1770  IF A$ = "N" OR A$ = "n" THEN 420
    1780  GOTO 1750
    1790  HOME : END 
    1800 :
    1810  REM   FILENAME INPUT ROUTINE
    1820 :
    1830  HOME :N$ = "":ESCF = 0
    1840  VTAB 2: PRINT "ENTER FILENAME FOR DOCUMENT": PRINT : PRINT 
    1850  PRINT "PRESS '?' TO CATALOG DISK": PRINT 
    1860  PRINT "ESCAPE ON 1ST CHAR RETURNS TO MAIN MENU": PRINT 
    1870  PRINT "ESCAPE ON ANY OTHER CHARACTER": PRINT " CANCELS INPUT AND STARTS OVER": PRINT 
    1880  PRINT "RETURN ACCEPTS INPUT"
    1890  HTAB 1: VTAB 15: PRINT "FILENAME: ";
    1900  GET C$
    1910  IF C$ = E$ THEN ESCF = 1: RETURN 
    1920  IF C$ = "?" THEN  PRINT D$ LEFT$ ("CATALOG",7 - 4 * PRODOS)",S"ST",D"DR: HTAB 1: VTAB 24: PRINT "PRESS RETURN TO CONTINUE: ";: GET A$: GOTO 1830
    1930 AN =  ASC (C$)
    1940  IF AN > 96 AND AN < 123 THEN AN = AN - 32
    1950  IF AN < 65 OR AN > 90 THEN MSG$ = "FIRST POSITION MUST BE A LETTER": GOSUB 2250: GOTO 1830
    1960  PRINT  CHR$ (AN)
    1970 N$ =  CHR$ (AN)
    1980  FOR K = 1 TO 15
    1990  HTAB 1: VTAB 18: CALL  - 958
    2000  VTAB 15: HTAB (11 + K)
    2010  GET C$
    2020  IF C$ = E$ THEN K = 15: NEXT : GOTO 1830
    2030  IF C$ =  CHR$ (8) AND K = 1 THEN K = 15: NEXT : GOTO 1830
    2040  IF C$ =  CHR$ (8) THEN K = K - 1: HTAB (11 + K): PRINT " ":N$ =  LEFT$ (N$,K): GOTO 2000
    2050  IF C$ = R$ THEN LC = K:K = 15: GOTO 2110
    2060 AN =  ASC (C$)
    2070  IF AN > 96 AND AN < 123 THEN AN = AN - 32
    2080  IF (AN < 65 OR AN > 90) AND (AN < 48 OR AN > 57) AND AN <  > 46 THEN MSG$ = "CHARACTER CANNOT BE USED IN FILENAME": GOSUB 2250: GOTO 1990
    2090  PRINT  CHR$ (AN)
    2100 N$ = N$ +  CHR$ (AN)
    2110  NEXT 
    2120  IF C$ <  > R$ THEN MSG$ = "FILENAME TOO LONG, LIMIT - 15 CHARACTERS": GOSUB 2250: GOTO 1830
    2130 FL$ = N$
    2140  FOR I = 0 TO 15
    2150  POKE FADDR + I,0
    2160  NEXT 
    2170  FOR K = 1 TO  LEN (N$)
    2180  POKE FADDR - 1 + K, ASC ( MID$ (N$,K,1)) + 128
    2190  NEXT 
    2200  POKE FADDR + LC,0
    2210  RETURN 
    2220 :
    2230  REM   ERROR MESSAGES
    2240 :
    2250  PRINT B$
    2260  HTAB 1: VTAB 18
    2270  PRINT MSG$: PRINT : PRINT 
    2280  PRINT "PRESS RETURN AND TRY AGAIN: ";: POKE  - 16368,0: GET AA$
    2290  RETURN 
    2300 :
    2310  REM   PRINTER MARGIN ROUTINE
    2320 :
    2330  HOME :N$ = "":ESCF = 0
    2340  VTAB 2: PRINT "ENTER VALUE FOR "M$: PRINT "MAXIMUM "MA$" - MINIMUM "MI$: PRINT 
    2350  PRINT "ESCAPE ON 1ST CHAR RETURNS TO MAIN MENU": PRINT 
    2360  PRINT "ESCAPE ON ANY OTHER CHARACTER": PRINT " CANCELS INPUT AND STARTS OVER": PRINT 
    2370  PRINT "RETURN ACCEPTS INPUT"
    2380  PRINT : PRINT "RETURN ON 1ST CHAR ACCEPTS DEFAULT (1.0)"
    2390  HTAB 1: VTAB 15: PRINT M$":  1.0"
    2400  HTAB 5: VTAB 15
    2410  GET C$
    2420  IF C$ = E$ THEN ESCF = 1: RETURN 
    2430  IF C$ = R$ THEN N$ = "1.0": RETURN 
    2440 AN =  ASC (C$)
    2450  IF AN < 48 OR AN > 57 THEN MSG$ = M3$: GOSUB 2250: GOTO 2330
    2460  PRINT C$;: CALL  - 868
    2470 N$ = C$
    2480  FOR K = 1 TO 3
    2490  HTAB 1: VTAB 18: CALL  - 958
    2500  VTAB 15: HTAB (5 + K)
    2510  GET C$
    2520  IF C$ = E$ THEN K = 3: NEXT : GOTO 2330
    2530  IF C$ =  CHR$ (8) AND K = 1 THEN K = 3: NEXT : GOTO 2330
    2540  IF C$ =  CHR$ (8) THEN K = K - 1: HTAB (5 + K): PRINT " ":N$ =  LEFT$ (N$,K): GOTO 2500
    2550  IF C$ = R$ THEN K = 3: GOTO 2600
    2560 AN =  ASC (C$)
    2570  IF (AN < 48 OR AN > 57) AND AN <  > 46 THEN MSG$ = M3$: GOSUB 2250: GOTO 2490
    2580  PRINT C$
    2590 N$ = N$ + C$
    2600  NEXT 
    2610  IF C$ <  > R$ THEN MSG$ = "INPUT TOO LONG, LIMIT - 3 CHARACTERS": GOSUB 2250: GOTO 2330
    2620  RETURN 
    2630 :
    2640  REM  ERASE CURRENT DOCUMENT?
    2650 :
    2660  HOME :ESCF = 0: VTAB 8: PRINT "YOU ARE ABOUT TO ERASE": PRINT "THE CURRENT DOCUMENT."
    2670  VTAB 12: PRINT "DO YOU REALLY WANT TO DO THIS? (Y/N) ";
    2680  GET A$
    2690  IF A$ = "N" OR A$ = "n" THEN ESCF = 1: RETURN 
    2700  IF A$ <  > "Y" AND A$ <  > "y" THEN 2680
    2710  RETURN 
    2720 :
    2730  REM  SELECT SLOT AND DRIVE
    2740 :
    2750  HOME : VTAB 1: PRINT "WHICH SLOT DO YOU WANT TO USE? (2-7) ";
    2760  GET A$
    2770  IF A$ =  > "2" AND A$ <  =  CHR$ (54 + PRODOS) THEN  PRINT A$:ST =  VAL (A$): GOTO 2790
    2780  GOTO 2760
    2790  VTAB 5: PRINT "WHICH DISK DRIVE": PRINT "DO YOU WANT TO USE? (1-2) ";
    2800  GET A$
    2810  IF A$ = "1" OR A$ = "2" THEN  PRINT A$:DR =  VAL (A$): GOTO 2830
    2820  GOTO 2800
    2830  POKE 216,0: ONERR  GOTO 2870: IF PRODOS THEN  PRINT D$"PREFIX,S";ST;",D";DR:
    2840  IF PRODOS THEN  GOTO 420
    2850  PRINT D$"VERIFY JUNK,S";ST;",D";DR
    2860  GOTO 420
    2870  POKE 216,0:EN =  PEEK (222):EL =  PEEK (218) + 256 *  PEEK (219): IF EL = 2850 AND EN = 6 THEN 420
    2880  VTAB 23: PRINT "DISK ERROR": PRINT "PRESS RETURN TO CONTINUE ";: POKE  - 16368,0: GET AA$: GOTO 420
    2890 :
    2900  REM  DATA FOR MAIN MENU
    2910 :
    2920  DATA  9,MAIN MENU,START NEW DOCUMENT,LOAD DOCUMENT,SAVE DOCUMENT,RENAME DOCUMENT,CONTINUE WITH CURRENT DOCUMENT,PRINT DOCUMENT,HELP,SET SLOT/DRIVE,QUIT
    2930 :
    2940  REM   MENU HANDLER
    2950 :
    2960 SL = SE
    2970 N = SL:OS = SL: GOSUB 3000:Z = 0: VTAB 24: HTAB PX: CALL  - 868: POKE  - 16368,0
    2980  VTAB 24: HTAB PX: PRINT SL;: WAIT  - 16384,128:Z =  PEEK ( - 16384) - 128: IF Z >  = 49 AND Z <  = MX + 48 THEN SL = Z - 48:N = OS: GOSUB 3000: GOTO 2970
    2990 Z = (Z = 21 OR Z = 10) - (Z = 8 OR Z = 11) + 10 * (Z = 13) + 20 * (Z = 27): ON  NOT Z GOTO 2980:SL = SL + Z * (Z < 10):SL = SL - MX * (SL > MX) + MX * (SL < 1):N = OS: GOSUB 3000: ON Z < 10 GOTO 2970:SE = SL: POKE  - 16368,0: RETURN 
    3000  VTAB 3 + 2 * N: HTAB SX: PRINT X$(SL = OS);: RETURN 
    3010 :
    3020  REM   PRINT A MENU
    3030 :
    3040  HOME :TL$ = MENU$(0): VTAB 1: PRINT "NIBBLEWRITER   (C)1988   MICROSPARC,INC.": VTAB 2: FOR I = 1 TO 40: PRINT "-";: NEXT 
    3050  VTAB 3: HTAB  INT ((40 -  LEN (TL$)) / 2)
    3060  PRINT TL$
    3070  FOR I = 1 TO MITEMS: VTAB 3 + 2 * I: HTAB 8: PRINT I". "MENU$(I): NEXT 
    3080  VTAB 24: HTAB 1: PRINT "USE ARROWS/NUMBERS & PRESS RETURN: ";
    3090  RETURN 
    3100 :
    3110  REM  DISK ERRORS
    3120 :
    3130  HOME : VTAB 10
    3140  POKE 216,0
    3150  IF  PEEK (222) = 6 OR  PEEK (222) = 7 THEN MSG$ = "FILE (" + FL$ + ")" +  CHR$ (13) + "IS NOT ON THIS DISK.": ON (( PEEK (218) + 256 *  PEEK (219) = 320) + 1) GOTO 3210,3230
    3160  IF  PEEK (222) = 13 THEN MSG$ = "FILE (" + FL$ + ")" +  CHR$ (13) + "IS NOT A BINARY FILE.": GOTO 3210
    3170  IF  PEEK (222) = 9 OR  PEEK (222) = 17 THEN MSG$ = "DISK OR DIRECTORY IS FULL.": GOTO 3210
    3180  IF  PEEK (222) = 10 THEN MSG$ = "EXISTING FILE (" + FL$ + ")" +  CHR$ (13) + "IS LOCKED.": GOTO 3210
    3190  PRINT "SYSTEM ERROR #"; PEEK (222);" HAS OCCURRED"
    3200  PRINT "AT LINE #"; PEEK (218) +  PEEK (219) * 256:MSG$ = ""
    3210  GOSUB 2250
    3220  GOTO 420
    3230  VTAB 24: PRINT "BINARY FILE NOT FOUND": END
  • Microchess for the KIM-1

    Microchess for the KIM-1

    https://obsolescenceguaranteed.blogspot.com/2014/06/6502-microchess-on-arduino.html

    https://www.benlo.com/microchess/index.html

    Game Hex Dump

    Assembly Listing

    ;***********************************************************************
    ;
    ;  Kim-1 MicroChess (c) 1976-2005 Peter Jennings, www.benlo.com 
    ;
    ;***********************************************************************
    
    ; All rights reserved.
    
    ; Redistribution and use in source and binary forms, with or without
    ; modification, are permitted provided that the following conditions
    ; are met:
    ; 1. Redistributions of source code must retain the above copyright
    ;    notice, this list of conditions and the following disclaimer.
    ; 2. Redistributions in binary form must reproduce the above copyright
    ;    notice, this list of conditions and the following disclaimer in the
    ;    documentation and/or other materials provided with the distribution.
    ; 3. The name of the author may not be used to endorse or promote products
    ;    derived from this software without specific prior written permission.
    
    ; THIS SOFTWARE IS PROVIDED BY THE AUTHOR ''AS IS'' AND ANY EXPRESS OR
    ; IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
    ; OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
    ; IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
    ; INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
    ; NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
    ; DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
    ; THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
    ; (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
    ; THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
    
    ;
    ; modified by Daryl Rictor to work over a 
    ; serial terminal connection, August 2002.
    ;
    ; Updated with corrections to earlier OCR errors by Bill Forster, August 2005.
    ;
       cpu 65c02
       page 0,132
    ;
    ; 6551 I/O Port Addresses
    ;
    ACIADat	= 	$7F70
    ACIASta	=	$7F71
    ACIACmd	=	$7F72
    ACIACtl	=	$7F73
    ;
    ; page zero variables
    ;
    BOARD   =	$50 
    BK      =	$60 
    PIECE   =	$B0 
    SQUARE  =	$B1 
    SP2     =	$B2 
    SP1     =	$B3 
    INCHEK  =	$B4 
    STATE   =	$B5 
    MOVEN   =	$B6 
    REV	=       $B7
    OMOVE   =	$DC 
    WCAP0   =	$DD 
    COUNT   =	$DE 
    BCAP2   =	$DE 
    WCAP2   =	$DF 
    BCAP1   =	$E0 
    WCAP1   =	$E1 
    BCAP0   =	$E2 
    MOB     =	$E3 
    MAXC    =	$E4 
    CC      =	$E5 
    PCAP    =	$E6 
    BMOB    =	$E3 
    BMAXC   =	$E4 
    BMCC    =	$E5 		; was BCC (TASS doesn't like it as a label)
    BMAXP   =	$E6 
    XMAXC   =	$E8 
    WMOB    =	$EB 
    WMAXC   =	$EC 
    WCC     =	$ED 
    WMAXP   =	$EE 
    PMOB    =	$EF 
    PMAXC   =	$F0 
    PCC     =	$F1 
    PCP     =	$F2 
    OLDKY   =	$F3 
    BESTP   =	$FB 
    BESTV   =	$FA 
    BESTM   =	$F9 
    DIS1    =	$FB 
    DIS2    =	$FA 
    DIS3    =	$F9 
    temp    =       $FC
    ;
    ;
    ;
    		*=$1000			; load into RAM @ $1000-$15FF
    
    		LDA     #$00		; REVERSE TOGGLE
    		STA     REV
                    JSR     Init_6551
    CHESS		CLD			; INITIALIZE
    		LDX	#$FF		; TWO STACKS
    		TXS	
    		LDX	#$C8
    		STX	SP2
    ;		
    ;       ROUTINES TO LIGHT LED
    ;       DISPLAY AND GET KEY
    ;       FROM KEYBOARD
    ;		
    OUT		JSR	pout		; DISPLAY AND
    		JSR	KIN		; GET INPUT   *** my routine waits for a keypress
    ;		CMP	OLDKY		; KEY IN ACC  *** no need to debounce
    ;		BEQ	OUT		; (DEBOUNCE)
    ;		STA	OLDKY
    ;		
    		CMP	#$43		; [C]
    		BNE	NOSET		; SET UP
    		LDX	#$1F		; BOARD
    WHSET		LDA	SETW,X		; FROM
    		STA	BOARD,X		; SETW
    		DEX	
    		BPL	WHSET
    		LDX	#$1B		; *ADDED
    		STX	OMOVE		; INITS TO $FF
    		LDA	#$CC		; Display CCC
    		BNE	CLDSP
    ;		
    NOSET		CMP	#$45		; [E]
    		BNE	NOREV		; REVERSE
    		JSR	REVERSE        	; BOARD IS
    		SEC
    		LDA	#$01
    		SBC	REV
    		STA	REV		; TOGGLE REV FLAG
    		LDA	#$EE            ; IS
    		BNE	CLDSP
    ;		
    NOREV		CMP	#$40			; [P]
    		BNE	NOGO           	; PLAY CHESS
    		JSR	GO
    CLDSP		STA	DIS1          	; DISPLAY
    		STA	DIS2         	; ACROSS
    		STA	DIS3          	; DISPLAY
    		BNE	CHESS
    ;		
    NOGO		CMP	#$0D            ; [Enter]
    		BNE	NOMV          	; MOVE MAN
    		JSR	MOVE          	; AS ENTERED
    		JMP	DISP
    NOMV		CMP     #$41		; [Q] ***Added to allow game exit***
    		BEQ     DONE		; quit the game, exit back to system.  
    		JMP	INPUT		; process move
    DONE		JMP     $FF00		; *** MUST set this to YOUR OS starting address
    ;		
    ;       THE ROUTINE JANUS DIRECTS THE
    ;       ANALYSIS BY DETERMINING WHAT
    ;       SHOULD OCCUR AFTER EACH MOVE
    ;       GENERATED BY GNM
    ;		
    ;		
    ;
    JANUS		LDX	STATE
    		BMI	NOCOUNT
    ;		
    ;       THIS ROUTINE COUNTS OCCURRENCES
    ;       IT DEPENDS UPON STATE TO INDEX
    ;       THE CORRECT COUNTERS
    ;		
    COUNTS		LDA	PIECE
    		BEQ	OVER           	; IF STATE=8
    		CPX 	#$08           	; DO NOT COUNT
    		BNE	OVER          	; BLK MAX CAP
    		CMP	BMAXP        	; MOVES FOR
    		BEQ	XRT           	; WHITE
    ; 		
    OVER		INC	MOB,X          	; MOBILITY
    		CMP 	#$01           	;  + QUEEN
    		BNE	NOQ           	; FOR TWO
    		INC	MOB,X
    ;		
    NOQ		BVC	NOCAP
    		LDY	#$0F           	; CALCULATE
    		LDA	SQUARE       	; POINTS
    ELOOP		CMP	BK,Y           	; CAPTURED
    		BEQ	FOUN          	; BY THIS
    		DEY			; MOVE
    		BPL	ELOOP
    FOUN		LDA	POINTS,Y
    		CMP	MAXC,X
    		BCC	LESS          	; SAVE IF
    		STY	PCAP,X         	; BEST THIS
    		STA	MAXC,X         	; STATE
    ;		
    LESS		CLC	
    		PHP			; ADD TO
    		ADC	CC,X           	; CAPTURE
    		STA	CC,X           	; COUNTS
    		PLP	
    ;		
    NOCAP		CPX	#$04
    		BEQ	ON4
    		BMI	TREE          	;(=00 ONLY)
    XRT		RTS	
    ;		
    ;      GENERATE FURTHER MOVES FOR COUNT
    ;      AND ANALYSIS	
    ;		
    ON4		LDA	XMAXC        	; SAVE ACTUAL 
    		STA	WCAP0         	; CAPTURE
    		LDA	#$00           	; STATE=0
    		STA	STATE
    		JSR	MOVE          	; GENERATE
    		JSR	REVERSE       	; IMMEDIATE
    		JSR	GNMZ         	; REPLY MOVES  
    		JSR	REVERSE
    ;		
    		LDA	#$08       	; STATE=8
    		STA	STATE        	; GENERATE
    		JSR	GNM          	; CONTINUATION
    		JSR	UMOVE         	; MOVES
    ;		
    		JMP	STRATGY       	; FINAL EVALUATION
    NOCOUNT	CPX	#$F9
    		BNE	TREE
    ;		
    ;      DETERMINE IF THE KING CAN BE
    ;      TAKEN, USED BY CHKCHK
    ;		
    		LDA	BK           	; IS KING
    		CMP	SQUARE       	; IN CHECK?
    		BNE	RETJ          	; SET INCHEK=0
    		LDA	#$00           	; IF IT IS
    		STA	INCHEK
    RETJ		RTS	
    ;		
    ;      IF A PIECE HAS BEEN CAPTURED BY
    ;      A TRIAL MOVE, GENERATE REPLIES &
    ;      EVALUATE THE EXCHANGE GAIN/LOSS
    ;		
    TREE		BVC	RETJ          	; NO CAP
    		LDY	#$07           	; (PIECES)
    		LDA	SQUARE
    LOOPX		CMP	BK,Y
    		BEQ	FOUNX
    		DEY	
    		BEQ	RETJ          	; (KING)
    		BPL	LOOPX         	; SAVE
    FOUNX		LDA	POINTS,Y       	; BEST CAP
    		CMP	BCAP0,X        	; AT THIS
    		BCC	NOMAX         	; LEVEL
    		STA	BCAP0,X
    NOMAX		DEC	STATE
    		LDA	#$FB           	; IF STATE=FB
    		CMP	STATE        	; TIME TO TURN
    		BEQ	UPTREE        	; AROUND
    		JSR	GENRM         	; GENERATE FURTHER
    UPTREE		INC	STATE        	; CAPTURES
    		RTS	
    ;		
    ;      THE PLAYER'S MOVE IS INPUT
    ;		
    INPUT		CMP	#$08           	; NOT A LEGAL
    		BCS	ERROR      	; SQUARE #
    		JSR	DISMV
    DISP		LDX	#$1F
    SEARCH		LDA	BOARD,X
    		CMP	DIS2
    		BEQ	HERE          	; DISPLAY
    		DEX			; PIECE AT    
    		BPL	SEARCH        	; FROM
    HERE		STX	DIS1         	; SQUARE
    		STX	PIECE
    ERROR		JMP	CHESS
    ;		
    ;      GENERATE ALL MOVES FOR ONE
    ;      SIDE, CALL JANUS AFTER EACH
    ;      ONE FOR NEXT STEP
    ;		
    ;
    GNMZ		LDX	#$10            ; CLEAR
    GNMX		LDA	#$00            ; COUNTERS
    CLEAR		STA	COUNT,X
    		DEX	
    		BPL	CLEAR
    ;		
    GNM		LDA	#$10            ; SET UP
    		STA	PIECE        	; PIECE
    NEWP		DEC	PIECE        	; NEW PIECE
    		BPL	NEX           	; ALL DONE?
    		RTS			;    -YES
    ;		
    NEX		JSR	RESET        	; READY
    		LDY	PIECE        	; GET PIECE
    		LDX	#$08
    		STX	MOVEN        	; COMMON START
    		CPY	#$08            ; WHAT IS IT?
    		BPL	PAWN          	; PAWN
    		CPY	#$06
    		BPL	KNIGHT        	; KNIGHT
    		CPY	#$04
    		BPL	BISHOP       	; BISHOP
    		CPY	#$01
    		BEQ	QUEEN         	; QUEEN
    		BPL	ROOK          	; ROOK
    ;		
    KING		JSR	SNGMV         	; MUST BE KING!
    		BNE	KING          	; MOVES
    		BEQ	NEWP          	; 8 TO 1
    QUEEN		JSR	LINE
    		BNE	QUEEN         	; MOVES
    		BEQ	NEWP          	; 8 TO 1
    ;		
    ROOK		LDX	#$04
    		STX	MOVEN        	; MOVES
    AGNR		JSR	LINE          	; 4 TO 1
    		BNE	AGNR
    		BEQ	NEWP
    ;		
    BISHOP		JSR	LINE
    		LDA	MOVEN        	; MOVES
    		CMP	#$04           	; 8 TO 5
    		BNE	BISHOP
    		BEQ	NEWP
    ;		
    KNIGHT		LDX	#$10
    		STX	MOVEN        	; MOVES
    AGNN		JSR	SNGMV         	; 16 TO 9
    		LDA	MOVEN
    		CMP	#$08
    		BNE	AGNN
    		BEQ	NEWP
    ;		
    PAWN		LDX	#$06
    		STX	MOVEN
    P1		JSR	CMOVE         	; RIGHT CAP?
    		BVC	P2
    		BMI	P2
    		JSR	JANUS         	; YES
    P2		JSR	RESET
    		DEC	MOVEN        	; LEFT CAP?
    		LDA	MOVEN
    		CMP	#$05
    		BEQ	P1
    P3		JSR	CMOVE         	; AHEAD
    		BVS	NEWP          	; ILLEGAL
    		BMI	NEWP
    		JSR	JANUS
    		LDA	SQUARE       	; GETS TO
    		AND	#$F0           	; 3RD RANK?
    		CMP	#$20
    		BEQ	P3            	; DO DOUBLE
    		JMP	NEWP
    ;		
    ;      CALCULATE SINGLE STEP MOVES
    ;      FOR K,N	
    ;		
    SNGMV		JSR	CMOVE        	; CALC MOVE
    		BMI	ILL1           	; -IF LEGAL
    		JSR	JANUS           ; -EVALUATE
    ILL1		JSR	RESET
    		DEC	MOVEN
    		RTS	
    ;		
    ;     CALCULATE ALL MOVES DOWN A
    ;     STRAIGHT LINE FOR Q,B,R
    ;		
    LINE		JSR	CMOVE         	; CALC MOVE
    		BCC	OVL            	; NO CHK
    		BVC	LINE		; NOCAP       
    OVL		BMI	ILL             ; RETURN
    		PHP	
    		JSR	JANUS         	; EVALUATE POSN
    		PLP	
    		BVC	LINE          	; NOT A CAP
    ILL		JSR	RESET         	; LINE STOPPED
    		DEC	MOVEN         	; NEXT DIR
    		RTS	
    ;		
    ;      EXCHANGE SIDES FOR REPLY
    ;      ANALYSIS	
    ;		
    REVERSE		LDX	#$0F
    ETC		SEC	
    		LDY	BK,X           	; SUBTRACT
    		LDA 	#$77           	; POSITION
    		SBC  	BOARD,X        	; FROM 77
    		STA  	BK,X
    		STY  	BOARD,X         ; AND
    		SEC	
    		LDA	#$77           	; EXCHANGE
    		SBC 	BOARD,X        	; PIECES
    		STA  	BOARD,X
    		DEX	
    		BPL   	ETC
    		RTS	
    ;		
    ;        CMOVE CALCULATES THE TO SQUARE
    ;        USING SQUARE AND THE MOVE
    ;       TABLE,  FLAGS SET AS FOLLOWS:
    ;       N - ILLEGAL MOVE
    ;       V - CAPTURE (LEGAL UNLESS IN CH)
    ;       C - ILLEGAL BECAUSE OF CHECK
    ;       [MY THANKS TO JIM BUTTERFIELD
    ;        WHO WROTE THIS MORE EFFICIENT
    ;        VERSION OF CMOVE]
    ;		
    CMOVE		LDA	SQUARE       	; GET SQUARE
    		LDX	MOVEN       	; MOVE POINTER
    		CLC	
    		ADC	MOVEX,X        	; MOVE LIST
    		STA	SQUARE       	; NEW POS'N
    		AND	#$88
    		BNE	ILLEGAL       	; OFF BOARD
    		LDA	SQUARE
    ;			
    		LDX	#$20
    LOOP		DEX			; IS TO
    		BMI	NO            	; SQUARE
    		CMP  	BOARD,X        	; OCCUPIED?
    		BNE   	LOOP
    ;			
    		CPX	#$10            ; BY SELF?
    		BMI   	ILLEGAL
    ;			
    		LDA	#$7F		; MUST BE CAP!
    		ADC	#$01            ; SET V FLAG
    		BVS   	SPX 	        ; (JMP)
    ;			
    NO		CLV			; NO CAPTURE
    ;			
    SPX		LDA  	STATE         	; SHOULD WE
    		BMI   	RETL           	; DO THE
    		CMP	#$08 	        ; CHECK CHECK?
    		BPL  	RETL
    ;			
    ;        CHKCHK REVERSES SIDES
    ;       AND LOOKS FOR A KING
    ;       CAPTURE TO INDICATE
    ;       ILLEGAL MOVE BECAUSE OF
    ;       CHECK  SINCE THIS IS
    ;       TIME CONSUMING, IT IS NOT
    ;       ALWAYS DONE	
    ;		
    CHKCHK	        PHA			; STATE
    		PHP	
    		LDA	#$F9
    		STA	STATE         	; GENERATE
    		STA	INCHEK        	; ALL REPLY
    		JSR	MOVE          	; MOVES TO
    		JSR	REVERSE       	; SEE IF KING
    		JSR	GNM           	; IS IN
    		JSR	RUM           	; CHECK
    		PLP	
    		PLA	
    		STA	STATE
    		LDA	INCHEK
    		BMI	RETL           	; NO - SAFE
    		SEC			; YES - IN CHK
    		LDA	#$FF
    		RTS	
    ;		
    RETL		CLC			; LEGAL
    		LDA	#$00            ; RETURN
    		RTS	
    ;		
    ILLEGAL	LDA	#$FF
    		CLC			; ILLEGAL
    		CLV			; RETURN
    		RTS	
    ;		
    ;       REPLACE PIECE ON CORRECT SQUARE
    ;		
    RESET		LDX	PIECE      	; GET LOGAT
    		LDA	BOARD,X        	; FOR PIECE
    		STA	SQUARE       	; FROM BOARD
    		RTS	
    ;		
    ;		
    ;		
    GENRM		JSR	MOVE          	; MAKE MOVE
    GENR2		JSR	REVERSE      	; REVERSE BOARD
    		JSR	GNM          	; GENERATE MOVES
    RUM		JSR	REVERSE   	; REVERSE BACK
    ;		
    ;       ROUTINE TO UNMAKE A MOVE MADE BY
    ;	  MOVE
    ;		
    UMOVE		TSX			; UNMAKE MOVE
    		STX	SP1
    		LDX	SP2           	; EXCHANGE
    		TXS			; STACKS
    		PLA			; MOVEN
    		STA	MOVEN
    		PLA			; CAPTURED
    		STA	PIECE        	; PIECE
    		TAX	
    		PLA			; FROM SQUARE
    		STA	BOARD,X
    		PLA			; PIECE
    		TAX	
    		PLA			; TO SOUARE
    		STA	SQUARE
    		STA	BOARD,X
    		JMP	STRV
    ;		
    ;       THIS ROUTINE MOVES PIECE
    ;       TO SQUARE, PARAMETERS
    ;       ARE SAVED IN A STACK TO UNMAKE
    ;       THE MOVE LATER
    ;		
    MOVE		TSX	
    		STX	SP1          	; SWITCH
    		LDX	SP2          	; STACKS
    		TXS	
    		LDA	SQUARE
    		PHA			; TO SQUARE
    		TAY	
    		LDX	#$1F
    CHECK		CMP	BOARD,X        	; CHECK FOR
    		BEQ	TAKE          	; CAPTURE
    		DEX	
    		BPL	CHECK
    TAKE		LDA	#$CC
    		STA	BOARD,X
    		TXA			; CAPTURED
    		PHA			; PIECE
    		LDX	PIECE
    		LDA	BOARD,X
    		STY	BOARD,X        	; FROM
    		PHA			; SQUARE
    		TXA	
    		PHA			; PIECE
    		LDA	MOVEN
    		PHA			; MOVEN
    STRV		TSX	
    		STX	SP2           	; SWITCH
    		LDX	SP1           	; STACKS
    		TXS			; BACK
    		RTS	
    ;			
    ;       CONTINUATION OF SUB STRATGY
    ;       -CHECKS FOR CHECK OR CHECKMATE
    ;       AND ASSIGNS VALUE TO MOVE
    ;		
    CKMATE	        LDX	BMAXC         	; CAN BLK CAP
    		CPX	POINTS       	; MY KING?
    		BNE	NOCHEK	
    		LDA	#$00           	; GULP!
    		BEQ	RETV          	; DUMB MOVE!
    ;		
    NOCHEK	LDX	BMOB         		; IS BLACK
    		BNE	RETV          	; UNABLE TO
    		LDX	WMAXP        	; MOVE AND
    		BNE	RETV          	; KING IN CH?
    		LDA	#$FF           	; YES! MATE
    ;		
    RETV		LDX	#$04            ; RESTORE
    		STX	STATE        	; STATE=4
    ;		
    ;       THE VALUE OF THE MOVE (IN ACCU)
    ;       IS COMPARED TO THE BEST MOVE AND
    ;       REPLACES IT IF IT IS BETTER
    ;		
    PUSH		CMP	BESTV         	; IS THIS BEST
    		BCC	RETP          	; MOVE SO FAR?
    		BEQ	RETP
    		STA	BESTV        	; YES!
    		LDA	PIECE        	; SAVE IT
    		STA	BESTP
    		LDA	SQUARE
    		STA	BESTM        	; FLASH DISPLAY
    RETP		LDA	#"."		; print ... instead of flashing disp
    		Jmp	syschout	; print . and return
    ;		
    ;       MAIN PROGRAM TO PLAY CHESS
    ;       PLAY FROM OPENING OR THINK
    ;		
    GO		LDX	OMOVE        	; OPENING?
    		BMI	NOOPEN          ; -NO   *ADD CHANGE FROM BPL
    		LDA	DIS3         	; -YES WAS
    		CMP	OPNING,X        ; OPPONENT'S
    		BNE	END            	; MOVE OK?
    		DEX	
    		LDA	OPNING,X       	; GET NEXT
    		STA	DIS1         	; CANNED
    		DEX			; OPENING MOVE
    		LDA	OPNING,X
    		STA	DIS3         	; DISPLAY IT
    		DEX	
    		STX	OMOVE        	; MOVE IT
    		BNE	MV2            	; (JMP)
    ;			
    END		LDA     #$FF		; *ADD - STOP CANNED MOVES
    		STA	OMOVE        	; FLAG OPENING
    NOOPEN	LDX	#$0C            	; FINISHED
    		STX	STATE        	; STATE=C
    		STX	BESTV        	; CLEAR BESTV
    		LDX	#$14           	; GENERATE P
    		JSR	GNMX          	; MOVES
    ;		
    		LDX	#$04           	; STATE=4
    		STX	STATE        	; GENERATE AND
    		JSR	GNMZ          	; TEST AVAILABLE
    ;	MOVES
    ;		
    		LDX	BESTV        	; GET BEST MOVE
    		CPX	#$0F           	; IF NONE
    		BCC	MATE          	; OH OH!
    ;		
    MV2		LDX	BESTP        	; MOVE
    		LDA	BOARD,X         ; THE
    		STA	BESTV        	; BEST
    		STX	PIECE        	; MOVE
    		LDA	BESTM
    		STA	SQUARE       	; AND DISPLAY
    		JSR	MOVE           	; IT
    		JMP	CHESS
    ;		
    MATE		LDA	#$FF           	; RESIGN
    		RTS			; OR STALEMATE
    ;		
    ;       SUBROUTINE TO ENTER THE
    ;       PLAYER'S MOVE
    ;		
    DISMV		LDX	#$04           	; ROTATE
    DROL		ASL	DIS3          	; KEY
    		ROL	DIS2         	; INTO
    		DEX			; DISPLAY
    		BNE	DROL		;
    		ORA	DIS3
    		STA	DIS3
    		STA	SQUARE
    		RTS	
    ;		
    ;       THE FOLLOWING SUBROUTINE ASSIGNS
    ;       A VALUE TO THE MOVE UNDER
    ;       CONSIDERATION AND RETURNS IT IN
    ;	THE ACCUMULATOR
    ;		
    
    STRATGY	CLC	
    		LDA	#$80
    		ADC	WMOB         	; PARAMETERS
    		ADC	WMAXC        	; WITH WEIGHT
    		ADC	WCC          	; OF 0.25
    		ADC	WCAP1
    		ADC	WCAP2
    		SEC	
    		SBC	PMAXC
    		SBC	PCC
    		SBC	BCAP0
    		SBC	BCAP1
    		SBC	BCAP2
    		SBC	PMOB
    		SBC	BMOB
    		BCS	POS           	; UNDERFLOW
    		LDA	#$00           	; PREVENTION
    POS		LSR	
    		CLC			; **************
    		ADC	#$40
    		ADC	WMAXC       	; PARAMETERS
    		ADC	WCC         	; WITH WEIGHT
    		SEC			; OF 0.5
    		SBC	BMAXC
    		LSR			; **************
    		CLC	
    		ADC	#$90
    		ADC	WCAP0       	; PARAMETERS
    		ADC	WCAP0       	; WITH WEIGHT
    		ADC	WCAP0       	; OF 1.0
    		ADC	WCAP0
    		ADC	WCAP1
    		SEC			; [UNDER OR OVER-
    		SBC	BMAXC        	; FLOW MAY OCCUR
    		SBC	BMAXC        	; FROM THIS
    		SBC	BMCC          	; SECTION]
    		SBC	BMCC
    		SBC	BCAP1
    		LDX	SQUARE      	; ***************
    		CPX	#$33
    		BEQ	POSN         	; POSITION
    		CPX	#$34           	; BONUS FOR
    		BEQ	POSN         	; MOVE TO
    		CPX	#$22           	; CENTRE
    		BEQ	POSN           	; OR
    		CPX	#$25           	; OUT OF
    		BEQ	POSN         	; BACK RANK
    		LDX	PIECE
    		BEQ	NOPOSN
    		LDY	BOARD,X
    		CPY	#$10
    		BPL	NOPOSN
    POSN		CLC
    		ADC	#$02
    NOPOSN	JMP	CKMATE       		; CONTINUE
    
    
    ;-----------------------------------------------------------------
    ; The following routines were added to allow text-based board
    ; display over a standard RS-232 port.
    ;
    POUT        	jsr 	pout9		; print CRLF
    		jsr     pout13		; print copyright
    		JSR	POUT10		; print column labels
    		LDY   	#$00		; init board location
    		JSR	POUT5		; print board horz edge
    POUT1		lDA   	#"|"		; print vert edge
    		JSR   	syschout	; PRINT ONE ASCII CHR - SPACE
    		LDX   	#$1F
    POUT2		TYA			; scan the pieces for a location match
                	CMP	BOARD,X		; match found?
                	BEQ   	POUT4		; yes; print the piece's color and type
                	DEX			; no
                	BPL	POUT2		; if not the last piece, try again
    		tya			; empty square	
    		and	#$01		; odd or even column?				
    		sta   	temp		; save it
    		tya  			; is the row odd or even
    		lsr			; shift column right 4 spaces 
    		lsr			;
    		lsr			;
    		lsr			;
    		and   	#$01		; strip LSB  
    		clc			; 
    		adc   	temp		; combine row & col to determine square color  
    		and   	#$01		; is board square white or blk?
    		beq	pout25 		; white, print space
    		lda   	#"*"		; black, print *
    		db	$2c		; used to skip over LDA #$20
    POUT25		LDA   	#$20		; ASCII space
    		JSR   	syschout	; PRINT ONE ASCII CHR - SPACE
    		JSR   	syschout	; PRINT ONE ASCII CHR - SPACE
    POUT3		INY			; 
    	          TYA			; get row number
                	AND   	#$08		; have we completed the row?	 
                	BEQ   	POUT1		; no, do next column
    		LDA   	#"|"		; yes, put the right edge on
    		JSR   	syschout	; PRINT ONE ASCII CHR - |             
    		jsr	pout12		; print row number
    		JSR   	POUT9		; print CRLF
                	JSR   	POUT5		; print bottom edge of board
    		CLC			; 
    		TYA			; 
    		ADC	#$08		; point y to beginning of next row
    		TAY			;
    		CPY   	#$80		; was that the last row?
    		BEQ   	POUT8		; yes, print the LED values
    		BNE   	POUT1		; no, do new row
    
    POUT4		LDA   	REV		; print piece's color & type
    		BEQ   	POUT41		;
    		LDA	cpl+16,X	;
    		BNE	POUT42		;
    POUT41		LDA   	cpl,x		;
    POUT42		JSR	syschout	;
    		lda	cph,x		;
    		jsr   	syschout	; 
    		BNE	POUT3		; branch always
    
    POUT5       	TXA			; print "-----...-----<crlf>"
    		PHA
    		LDX	#$19
    		LDA	#"-"
    POUT6		JSR   	syschout	; PRINT ONE ASCII CHR - "-"
    		DEX
    		BNE	POUT6
    		PLA
    		TAX
    		JSR	POUT9
    		RTS	 		
    
    POUT8		jsr	pout10		; 
    		LDA   	$FB
    		JSR   	syshexout	; PRINT 1 BYTE AS 2 HEX CHRS	
            	LDA   	#$20
    		JSR   	syschout	; PRINT ONE ASCII CHR - SPACE
            	LDA   	$FA
    		JSR   	syshexout	; PRINT 1 BYTE AS 2 HEX CHRS	
            	LDA   	#$20
    		JSR   	syschout	; PRINT ONE ASCII CHR - SPACE
            	LDA   	$F9
    		JSR   	syshexout	; PRINT 1 BYTE AS 2 HEX CHRS	
    
    POUT9      	LDA   	#$0D
    		JSR   	syschout	; PRINT ONE ASCII CHR - CR
            	LDA   	#$0A
    		JSR   	syschout	; PRINT ONE ASCII CHR - LF
                    RTS 
    
    pout10		ldx   	#$00		; print the column labels
    POUT11		lda	#$20		; 00 01 02 03 ... 07 <CRLF>
    		jsr   	syschout
    		txa
    		jsr	syshexout
    		INX
    		CPX   	#$08
    		BNE	POUT11
    		BEQ	POUT9
    POUT12		TYA
    		and 	#$70
    		JSR 	syshexout
    		rts
    
    Pout13		ldx   	#$00		; Print the copyright banner
    Pout14		lda   	banner,x
    		beq   	POUT15
    		jsr   	syschout
    		inx
    		bne   	POUT14
    POUT15		rts         
    
    KIN        	LDA   	#"?"
    		JSR   	syschout	; PRINT ONE ASCII CHR - ?
    		JSR   	syskin		; GET A KEYSTROKE FROM SYSTEM
                	AND   	#$4F            ; MASK 0-7, AND ALPHA'S
                	RTS
    ;
    ; 6551 I/O Support Routines
    ;
    ;
    Init_6551      lda   #$1F               ; 19.2K/8/1
                   sta   ACIActl            ; control reg 
                   lda   #$0B               ; N parity/echo off/rx int off/ dtr active low
                   sta   ACIAcmd            ; command reg 
                   rts                      ; done
    ;
    ; input chr from ACIA1 (waiting)
    ;
    syskin         lda   ACIASta            ; Serial port status             
                   and   #$08               ; is recvr full
                   beq   syskin             ; no char to get
                   Lda   ACIAdat            ; get chr
                   RTS                      ;
    ;
    ; output to OutPut Port
    ;
    syschout       PHA                      ; save registers
    ACIA_Out1      lda   ACIASta            ; serial port status
                   and   #$10               ; is tx buffer empty
                   beq   ACIA_Out1          ; no
                   PLA                      ; get chr
                   sta   ACIAdat            ; put character to Port
                   RTS                      ; done
    
    syshexout      PHA                     ;  prints AA hex digits
                   LSR                     ;  MOVE UPPER NIBBLE TO LOWER
                   LSR                     ;
                   LSR                     ;
                   LSR                     ;
                   JSR   PrintDig          ;
                   PLA                     ;
    PrintDig       AND   #$0F              ;  prints A hex nibble (low 4 bits)
                   PHY
                   TAY                     ;
                   LDA   Hexdigdata,Y      ;
                   PLY
                   jmp   syschout          ;
    
    Hexdigdata	asc	"0123456789ABCDEF"
    banner		asc	"MicroChess (c) 1996-2005 Peter Jennings, www.benlo.com"
    		db	$0d, $0a, $00
    cpl		asc	"WWWWWWWWWWWWWWWWBBBBBBBBBBBBBBBBWWWWWWWWWWWWWWWW"
    cph		asc	"KQRRBBNNPPPPPPPPKQRRBBNNPPPPPPPP"
    		db	$00
    ;
    ; end of added code
    ;
    ; BLOCK DATA
    		*= $1580
    SETW		db 	$03, $04, $00, $07, $02, $05, $01, $06
            	db 	$10, $17, $11, $16, $12, $15, $14, $13
            	db 	$73, $74, $70, $77, $72, $75, $71, $76
    	 	db	$60, $67, $61, $66, $62, $65, $64, $63
    
    MOVEX   	db 	$00, $F0, $FF, $01, $10, $11, $0F, $EF, $F1
    		db	$DF, $E1, $EE, $F2, $12, $0E, $1F, $21
    
    POINTS  	db 	$0B, $0A, $06, $06, $04, $04, $04, $04
    		db 	$02, $02, $02, $02, $02, $02, $02, $02
    
    OPNING  	db 	$99, $25, $0B, $25, $01, $00, $33, $25
    		db	$07, $36, $34, $0D, $34, $34, $0E, $52
            	db 	$25, $0D, $45, $35, $04, $55, $22, $06
    		db	$43, $33, $0F, $CC
    
    ;
    ;
    ; end of file
    ;
    
  • Word Processors in BASIC, Part 1

    Word Processors in BASIC, Part 1

    Quickwriter

    Found in June 1988 issue of Nibble magazine (Volume 9, Number 6).

    Archive.org link here.

    The project was alerted to the existence of a few text editors and word processors in Nibble magazine by someone on matrix.

    What we found was a great wealth of BASIC programs for the Apple II computer. We uncovered several particularly interesting BASIC word processors. Two that are of particular interest are Quickwriter and Nibblewriter.

    Both programs are quite long and involved, so instead of creating one enormous post, we decided to split the discussion up into two feature posts.

    diskM8 File Dump

    Please find an ASCII conversion of the BASIC dump obtained using the following commands:

    $ diskm8 -ingest /path/to/your/disk/images
    $ diskm8 -search "quickwriter"
    $ diskm8 -with-disk "your_disk_image.do" -file-extract "QUICKWRITER.BAS"

    Code Listing

    10  REM **********************
    20  REM *     TYPEWRITER     *
    30  REM *  BY JAMES D EVANS  *
    40  REM * COPYRIGHT (C) 1988 *
    50  REM * BY MICROSPARC, INC *
    60  REM * CONCORD, MA  01742 *
    70  REM **********************
    80  HIMEM: 38144:X =  FRE (0)
    90  ONERR  GOTO 2740
    100  GOSUB 2220
    110  GOTO 230
    120  REM **WARMSTART 80-COL CARD**
    130  ON  NOT PD GOTO 140: PRINT D$;"PR#A$C307": GOTO 150
    140  POKE 54,7: POKE 55,195: CALL 1002: PRINT 
    150  RETURN 
    160  REM **GET CHAR ROUTINE**
    170  POKE  - 16368,0: ON  NOT PLUS GOTO 180: PRINT  CHR$ (0);: GET A$: ON  NOT  LEN (A$) GOTO 170:B =  ASC (A$): GOTO 190
    180  INVERSE : PRINT " ";BS$;: NORMAL : WAIT  - 16384,128:B = ( PEEK ( - 16384) - 128):A$ =  CHR$ (B): POKE  - 16368,0: PRINT " ";BS$;: ON  NOT B GOTO 180
    190  RETURN 
    200  REM 
    210  REM ***MAIN PROGRAM***
    220  REM 
    230  FOR I = M TO M + 80: POKE I,160: NEXT 
    240  GOSUB 850: GOSUB 2050
    250 C = LM:LL = 0: POKE  - 16368,0
    260  VTAB 2: POKE H,C: INVERSE : PRINT  CHR$ ( PEEK (M + (C - LM)));: NORMAL : POKE H,C: PRINT  CHR$ (24);: ON  NOT PLUS GOTO 270: GET A$: GOTO 280
    270  WAIT  - 16384,128:A$ =  CHR$ ( PEEK ( - 16384) - 128): POKE  - 16368,0
    280  IF A$ < " " OR A$ =  CHR$ (127) THEN  GOSUB 330: GOTO 260
    290  PRINT A$: POKE M + C - LM, ASC (A$) + 128
    300 C = C + (C < RM - 1):LL = LL + (LL < RM - LM): POKE H,5: PRINT C + 1;" "
    310  GOTO 260
    320  REM **CTRL-CHAR EVALUATION**
    330  ON ( LEN (A$) = 0) GOTO 610: PRINT  CHR$ ( PEEK (M + (C - LM))); CHR$ (24)
    340  IF A$ =  CHR$ (127) THEN A$ =  CHR$ (4): ON C = LM GOTO 610:C = C - 1: POKE H,5: PRINT C + 1;" "
    350  IF A$ =  CHR$ (4) AND (LL + LM + 1) > C THEN LL = LL - 1: POKE M + RM - LM,160: FOR I = M + C - LM TO M + LL + 1: POKE I, PEEK (I + 1): NEXT : VTAB 2: POKE H,LM: POKE 8,RM - LM: CALL 768: PRINT : GOTO 610
    360  ON A$ <  >  CHR$ (15) OR C = (RM - 1) GOTO 370:LL = LL + (LL < (RM - LM - 1)): FOR I = M + LL TO M + C - LM STEP  - 1: POKE I, PEEK (I - 1): NEXT : POKE M + C - LM,160: VTAB 2: POKE H,LM: POKE 8,RM - LM: CALL 768: PRINT : GOTO 610
    370  IF A$ =  CHR$ (8) THEN C = C - (C > LM): POKE H,5: PRINT C + 1;" ": GOTO 610
    380  IF A$ =  CHR$ (21) THEN C = C + (C < RM - 1): POKE H,5: PRINT C + 1" ":LL = LL + ((C + 1 - LM) > LL): GOTO 610
    390  IF A$ =  CHR$ (9) THEN  GOSUB 940: GOTO 610
    400  IF A$ =  CHR$ (20) THEN TB(C + 1) =  NOT TB(C + 1):X = 160 * ( NOT TB(C + 1)) + 252 * (TB(C + 1)): PRINT : VTAB 4: POKE H,C: PRINT  CHR$ (X): GOTO 610
    410  IF A$ =  CHR$ (13) THEN  GOSUB 660: POP : GOTO 250
    420  IF A$ =  CHR$ (22) THEN RF = 1: VTAB 6: POKE H,20: PRINT "REVERSE LINEFEEDS ENABLED -- PRESS RETURN ";: GOSUB 170: PRINT : VTAB 6: PRINT LC$: GOTO 610
    430  IF A$ =  CHR$ (18) THEN A$ =  CHR$ (93): VTAB 2: POKE H,C: POP : GOTO 290
    440  IF A$ =  CHR$ (12) THEN A$ =  CHR$ (91): VTAB 2: POKE H,C: POP : GOTO 290
    450  IF A$ =  CHR$ (2) THEN A$ =  CHR$ (92):US = 1: VTAB 2: POKE H,C: PRINT A$: POKE M + C - LM,92: POP : GOTO 300
    460  IF A$ =  CHR$ (14) THEN A$ =  CHR$ (64): VTAB 2: POKE H,C: POP : GOTO 290
    470  IF A$ =  CHR$ (26) THEN  GOSUB 990: GOTO 610
    480  IF A$ =  CHR$ (7) THEN A$ =  CHR$ (95): VTAB 2: POKE H,C: POP : GOTO 290
    490  IF A$ =  CHR$ (24) THEN  GOSUB 1850
    500  IF A$ =  CHR$ (10) THEN  GOSUB 1260: POP : GOTO 260
    510  IF A$ =  CHR$ (19) THEN C = LM: PRINT : VTAB 3: POKE H,5: PRINT C + 1;" ": GOTO 610
    520  ON A$ <  >  CHR$ (5) GOTO 550: FOR I = M + (RM - LM - 1) TO M STEP  - 1: IF  PEEK (I) <  > 160 THEN C = LM + I - M + ((I - M) < (RM - LM - 1)):I = M: GOTO 540
    530  NEXT 
    540  PRINT : VTAB 3: POKE H,5: PRINT C + 1;" ": GOTO 610
    550  IF A$ =  CHR$ (23) THEN  GOSUB 1640: GOTO 610
    560  IF A$ =  CHR$ (6) THEN  GOSUB 1780: GOTO 610
    570  IF A$ =  CHR$ (16) THEN  GOSUB 1170: POP : GOTO 260
    580  IF A$ =  CHR$ (17) THEN  GOSUB 1340: GOTO 610
    590  IF A$ =  CHR$ (27) AND (C < (RM - 1)) THEN  GOSUB 1900: GOTO 610
    600  IF A$ =  CHR$ (30) THEN  GOSUB 2000
    610  RETURN 
    620  REM 
    630  REM ***UTILITY SUBROUTINES***
    640  REM 
    650  REM **PRINT LINE**
    660 X$ = "":X =  VAL (X$) +  PEEK (131) + 256 *  PEEK (132): POKE X,RM - LM: POKE X + 1,(M -  INT (M / 256) * 256): POKE X + 2, INT (M / 256):X$ =  MID$ (X$,1):AP$(R) = X$
    670  PRINT : PRINT D$;"PR#";SL
    680  PRINT  CHR$ (9);"80N";
    690  PRINT  TAB( LM);
    700  ON US GOTO 720
    710  PRINT AP$(R): GOTO 790
    720 J = 1
    730  FOR I = M TO M + LL
    740  ON  PEEK (I) <  > 92 GOTO 760:J =  NOT J: ON J GOTO 750: PRINT U1$;: GOTO 770
    750  PRINT U2$;: GOTO 770
    760  PRINT  CHR$ ( PEEK (I));
    770  NEXT 
    780  PRINT U2$
    790 R = R + 1:US = 0
    800  ON SP < 2 GOTO 810: PRINT : ON SP < 3 GOTO 810: PRINT : ON SP < 4 GOTO 810: PRINT 
    810  GOSUB 130
    820  GOSUB 870
    830  RETURN 
    840  REM **WINDOW**
    850  PRINT CL$
    860  FOR I = 1 TO LM: PRINT  CHR$ (255);: NEXT : POKE H,RM: FOR I = RM TO 79: PRINT  CHR$ (255);: NEXT 
    870  VTAB 1: POKE H,LM: POKE 8,RM - LM: CALL 768: PRINT 
    880  FOR I = M TO M + 80: POKE I,160: NEXT : VTAB 2: POKE H,LM: POKE 8,RM - LM: CALL 768: PRINT 
    890  VTAB 3: PRINT "COL: ";LM + 1;" "
    900  VTAB 5: PRINT "LINE:";R
    910  IF R > 300 THEN  VTAB 10: POKE H,19: PRINT  CHR$ (7);"NO MORE ROOM!  RESTART PROGRAM."
    920  RETURN 
    930  REM **TAB**
    940  FOR I = C + 1 + (C < RM - 1) TO RM - 1:C = I * TB(I) - 1: ON C > 0 GOTO 960: NEXT 
    950 C = RM - 1
    960 I = RM - 1: PRINT : VTAB 3: POKE H,5: PRINT C + 1: IF C + 1 > LL THEN LL = C + 1 - LM
    970  RETURN 
    980  REM **CENTER TEXT**
    990  PRINT : VTAB 6: POKE H,23: PRINT "CENTERING.....": PRINT : VTAB 2
    1000  FOR I = 0 TO LL
    1010  IF  PEEK (M + I) <  > 160 THEN X = I:I = LL: GOTO 1030
    1020  NEXT : GOTO 1140
    1030 Y = 0: FOR I = RM - LM - 1 TO 0 STEP  - 1
    1040 Y = Y + 1: IF  PEEK (M + I) <  > 160 THEN Y = Y - 1:I = 0: GOTO 1060
    1050  NEXT 
    1060 XL = RM - LM - X - Y: REM STRING LENGTH     
    1070 K = 0: FOR J = M + X TO M + X + XL - 1:K = K + ( PEEK (J) < 128): NEXT : REM HANDLE <ESC> AND UNDERLINE CODES
    1080 A = M + X:X$ = "":B =  VAL (X$) +  PEEK (131) + 256 *  PEEK (132): POKE B,XL: POKE B + 1,A -  INT (A / 256) * 256: POKE B + 2, INT (A / 256):X$ =  MID$ (X$,1)
    1090 J = 0:T =  INT ((RM - LM - XL - K) / 2) + K: IF (T + XL) > (RM - LM) THEN  PRINT : VTAB 6: POKE H,9: PRINT  CHR$ (7);"TOO MANY <ESC> CODES TO CENTER. PRESS RETURN TO RESUME TYPING ";: GOSUB 170: PRINT : VTAB 6: PRINT LC$: GOTO 1150
    1100  FOR I = M + X TO M + X + XL: POKE I,160: NEXT :
    1110  FOR I = M + T TO M + T + XL - 1:J = J + 1: POKE I, ASC ( MID$ (X$,J)): NEXT 
    1120  POKE H,LM: POKE 8,RM - LM: CALL 768
    1130 LL = T + XL:C = LM + T + XL: IF C >  = RM THEN C = C - 1
    1140  PRINT : VTAB 6: PRINT LC$: VTAB 3: POKE H,5: PRINT C + 1;" "
    1150  RETURN 
    1160  REM **PRINT TEST PATTERN**
    1170  PRINT : PRINT D$;"PR#";SL
    1180  PRINT  CHR$ (9);"80N";
    1190  PRINT  TAB( LM)"." TAB(  INT (((RM - LM) / 2) - 1))"." TAB(  INT (((RM - LM) / 2)))".";
    1200  IF  NOT RF THEN  PRINT : GOTO 1230
    1210  PRINT RF$
    1220  PRINT FF$
    1230  GOSUB 130
    1240  RETURN 
    1250  REM **ISSUE REVERSE LINEFEED**
    1260  ON  NOT RF GOTO 1320
    1270  PRINT : PRINT D$;"PR#";SL
    1280  PRINT  CHR$ (9);"80N";
    1290  PRINT RF$: PRINT RF$
    1300  PRINT FF$
    1310  GOSUB 130
    1320  RETURN 
    1330  REM **QUIT?**
    1340  PRINT : VTAB 8: POKE H,19: PRINT "Q)UIT   R)ESUME   S)TART ANEW": PRINT : HTAB 20: PRINT "PRESS Q, R, OR S:";: GOSUB 170:A$ =  CHR$ ( ASC (A$) - 32 * (A$ > "S"))
    1350  IF A$ = "Q" THEN  GOSUB 1390: PRINT CL$: END 
    1360  IF A$ = "R" THEN  PRINT : VTAB 8: PRINT LC$: VTAB 10: PRINT LC$: RETURN 
    1370  IF A$ = "S" THEN  GOSUB 1390: RUN 
    1380  GOTO 1340
    1390  PRINT : VTAB 8: PRINT LC$: VTAB 10: PRINT LC$;: POKE H,19: PRINT "SAVE THIS DOCUMENT? (Y/N)";: GOSUB 2870
    1400  IF A$ <  > "Y" AND A$ <  >  CHR$ (121) THEN 1620
    1410  PRINT : VTAB 10: PRINT LC$;: POKE H,19: PRINT "ENTER DOCUMENT NAME: ";: FOR I = 1 TO 15: PRINT "_";: NEXT 
    1420 HZ = 0:FL$ = "": POKE H,40
    1430  GOSUB 170: ON A$ >  CHR$ (31) GOTO 1480
    1440  ON A$ =  CHR$ (13) GOTO 1500
    1450  IF A$ =  CHR$ (8) AND (FL$ = "" OR  LEN (FL$) = 1) THEN 1410
    1460  IF A$ =  CHR$ (8) THEN HZ = HZ - 1: POKE H, PEEK (H) - 1:FL$ =  MID$ (FL$,1, LEN (FL$) - 1): GOTO 1430
    1470  ON A$ =  CHR$ (27) GOTO 1410: ON A$ < " " GOTO 1430
    1480  ON HZ = 15 GOTO 1430: IF A$ >  CHR$ (95) THEN A$ =  CHR$ ( ASC (A$) - 32)
    1490 FL$ = FL$ + A$: PRINT A$;:HZ = HZ + 1: GOTO 1430
    1500  ON FL$ = "" GOTO 1620
    1510  IF  MID$ (FL$,1,1) < "A" THEN  PRINT : VTAB 10: POKE H,19: PRINT LC$;"INVALID NAME -- PRESS RETURN TO REENTER ";: GOSUB 170: GOTO 1410
    1520  FOR I = 1 TO  LEN (FL$):X$ =  MID$ (FL$,I,1): IF X$ = " " THEN FL$ =  LEFT$ (FL$,I - 1) + "." +  RIGHT$ (FL$, LEN (FL$) - I): GOTO 1540
    1530  IF ((X$ < "0") AND (X$ <  > ".")) OR ((X$ > "9") AND (X$ < "A")) OR (X$ > "Z") THEN  PRINT : VTAB 10: POKE H,19: PRINT LC$;"INVALID NAME -- PRESS RETURN TO REENTER ";: GOSUB 170: GOTO 1410
    1540  NEXT 
    1550  PRINT : PRINT D$;"OPEN ";FL$;",D1"
    1560  PRINT D$;"CLOSE ";FL$
    1570  PRINT D$;"DELETE ";FL$;",D1"
    1580  PRINT D$;"OPEN "FL$;",D1"
    1590  PRINT D$;"WRITE ";FL$
    1600  FOR I = 1 TO R: PRINT AP$(I): NEXT 
    1610  PRINT D$;"CLOSE"
    1620  RETURN 
    1630  REM **SET MARGINS**
    1640  PRINT : VTAB 8: POKE H,19: PRINT "LEFT MARGIN...": VTAB 10: POKE H,19: PRINT "<-  ->    <RETURN> = ACCEPT"
    1650  PRINT : VTAB 3: POKE H,5: PRINT LM;" ": VTAB 2: POKE H,LM: PRINT  CHR$ (0);: GOSUB 170
    1660  IF A$ =  CHR$ (8) THEN LM = LM - (LM > 1): PRINT : VTAB 2: POKE H,LM: PRINT " "
    1670  IF A$ =  CHR$ (21) OR A$ =  CHR$ (32) THEN  IF LM < (RM - 2) THEN  PRINT : VTAB 2: POKE H,LM: PRINT  CHR$ (255):LM = LM + 1
    1680  IF A$ <  >  CHR$ (13) THEN 1650
    1690  PRINT : VTAB 8: POKE H,19: PRINT "RIGHT MARGIN..."
    1700  PRINT : VTAB 3: POKE H,5: PRINT RM;" ": VTAB 2: POKE H,RM - 1: PRINT  CHR$ (0);: GOSUB 170
    1710  IF A$ =  CHR$ (8) THEN RM = RM - (RM > LM + 2): PRINT : VTAB 2: POKE H,RM: PRINT  CHR$ (255)
    1720  IF A$ =  CHR$ (21) OR A$ =  CHR$ (32) THEN RM = RM + (RM < 79): PRINT : VTAB 2: POKE H,RM - 1: PRINT " "
    1730  IF A$ <  >  CHR$ (13) THEN 1700
    1740  PRINT : VTAB 8: PRINT LC$: VTAB 10: PRINT LC$
    1750 C = LM: PRINT : VTAB 3: POKE H,5: PRINT C + 1;" ": VTAB 2: POKE H,LM: POKE 8,RM - LM: CALL 768: PRINT 
    1760  RETURN 
    1770  REM **SELECT LINE SPACING**
    1780  PRINT : VTAB 10: POKE H,6: PRINT "ENTER NUMBER OF SPACES BETWEEN LINES (1-4):" SPC( 4)"(CURRENT=";SP;")";: POKE H,49: GOSUB 170
    1790  IF A$ =  CHR$ (13) THEN  GOTO 1820
    1800  IF A$ < "1" OR A$ > "4" THEN 1780
    1810 SP =  VAL (A$)
    1820  PRINT : VTAB 10: PRINT LC$
    1830  RETURN 
    1840  REM **TRUNCATE LINE**
    1850  VTAB 6: POKE H,14: PRINT "OKAY TO ERASE TEXT FROM CURSOR TO END OF LINE? (Y/N) ": VTAB 2: POKE H,C: GOSUB 170: ON (A$ = "N" OR A$ =  CHR$ (110)) GOTO 1870: IF A$ <  > "Y" AND A$ <  >  CHR$ (121) THEN 1850
    1860  FOR I = M + C - LM TO M + LL - 1: POKE I,160: NEXT : VTAB 2: POKE H,C: FOR I = 1 TO RM - C: PRINT " ";: NEXT :LL = C - LM: PRINT 
    1870  PRINT : VTAB 6: PRINT LC$
    1880  RETURN 
    1890  REM **ENTER <ESC> CODE**
    1900 A = C: VTAB 6: POKE H,13: PRINT "TYPE <ESC> CODE & PRESS <RETURN> TO RESUME TEXT ENTRY"
    1910  VTAB 2: POKE H,C: GOSUB 170: IF A$ =  CHR$ (13) THEN  PRINT : GOTO 1970
    1920  IF A$ =  CHR$ (8) THEN B =  PEEK (M + C - LM): POKE H,C: PRINT  CHR$ (B + 227 * (B = 27)):C = C - (C > A): POKE M + C - LM,160: VTAB 2: POKE H,C: PRINT " ": GOTO 1960
    1930  IF B < 27 THEN 1910
    1940  POKE M + C - LM,B:B = B + 227 * (B = 27): INVERSE : VTAB 2: POKE H,C: PRINT  CHR$ (B): NORMAL 
    1950 C = C + (C < RM - 1):LL = LL + (LL < C)
    1960  POKE H,5: PRINT C + 1;" ": GOTO 1910
    1970  VTAB 6: PRINT LC$
    1980  RETURN 
    1990  REM **CTRL-CODE TO PRINTER**
    2000  VTAB 6: POKE H,17: PRINT "TYPE CONTROL-CHARACTER TO BE SENT TO PRINTER: ";: GOSUB 170: ON ((B > 26) OR (B = 13)) GOTO 2020
    2010  PRINT : PRINT D$;"PR#";SL: PRINT  CHR$ (9);"80N";: PRINT A$;: GOSUB 130
    2020  PRINT : VTAB 6: PRINT LC$: IF B < 26 AND B <  > 13 THEN  VTAB 4: POKE H,79: INVERSE : PRINT  CHR$ (B + 64): NORMAL 
    2030  RETURN 
    2040  REM **HELP SCREEN**
    2050  PRINT : VTAB 11: FOR I = 1 TO 80: PRINT U$;: NEXT 
    2060  PRINT "<CTRL-B>: "; CHR$ (92);" (UNDERLINE TEXT)";: POKE H,39: PRINT V$ + " <CRTL-P>: PRINT TEST PATTERN"
    2070  PRINT "<CTRL-D>: CLOSE LINE (DELETE CHAR)";: POKE H,39: PRINT V$ + " <CTRL-Q>: QUIT OR START ANEW"
    2080  PRINT "<CTRL-E>: JUMP TO LAST CHARACTER";: POKE H,39: PRINT V$ + " <CTRL-R>: TYPE "; CHR$ (93)
    2090  PRINT "<CTRL-F>: SET PRINTER LINE SPACING";: POKE H,39: PRINT V$ + " <CTRL-S>: JUMP TO LINE START"
    2100  PRINT "<CTRL-G>: TYPE "; CHR$ (95);: POKE H,39: PRINT V$ + " <CTRL-T>: SET OR CLEAR TAB STOP"
    2110  PRINT "<CTRL-I>: TAB";: POKE H,39: PRINT V$ + " <CTRL-V>: ENABLE REVERSE LINEFEEDS"
    2120  PRINT "<CTRL-J>: REVERSE PRINTER LINEFEED";: POKE H,39: PRINT V$ + " <CTRL-W>: SET LINE WIDTH (MARGINS)"
    2130  PRINT "<CTRL-L>: TYPE "; CHR$ (91);: POKE H,39: PRINT V$ + " <CTRL-X>: ERASE TO END OF LINE "
    2140  PRINT "<CTRL-N>: TYPE "; CHR$ (64);: POKE H,39: PRINT V$ + " <CTRL-Z>: CENTER TEXT"
    2150  PRINT "<CTRL-O>: OPEN LINE";: POKE H,39: PRINT V$ + " <DELETE>: DESTRUCTIVE BACKSPACE"
    2160  PRINT "<CTRL-^>: SEND CONTROL CHAR TO PRINTER";: POKE H,39: PRINT V$ + " <ESC>   : EMBED PRINTER <ESC> CODES"
    2170  FOR I = 1 TO 80: PRINT U$;: NEXT 
    2180  RETURN 
    2190  REM 
    2200  REM ***GLOBAL SETUP***
    2210  REM 
    2220  TEXT : HOME 
    2230  DIM TB(80),AP$(300): REM TAB STOP AND TEXT STRING ARRAYS
    2240  REM **INSTALL BUFFER PRINTER**
    2250  FOR I = 768 TO 792: READ X: POKE I,X: NEXT 
    2260  DATA 169,149,133,7,160,0,132,6,177,6,201,27,208,2,169,126,32,7,195,200,196,8,208,240,96
    2270  REM **MACHINE AND DOS ID**
    2280 PLUS = ( PEEK (64435) = 234 OR  PEEK (64435) = 56):PD = ( PEEK (48640) = 76): REM IF PLUS THEN II OR II+; IF PD THEN PRODOS
    2290  REM ***PRINTER CODES***
    2300 U1$ =  CHR$ (27) +  CHR$ (88): REM ESC+X TURNS ON UNDERLINE
    2310 U2$ =  CHR$ (27) +  CHR$ (89): REM ESC+Y TURNS OFF UNDERLINE
    2320 FF$ =  CHR$ (27) +  CHR$ (102): REM ESC+LOWERCASE F ACTIVATES FORWARD LINEFEEDS
    2330 RF$ =  CHR$ (27) +  CHR$ (114): REM ESC+LOWERCASE R ACTIVATES REVERSE LINEFEEDS
    2340  REM **ALL-PURPOSE REALS**
    2350 I = 0:J = 0:K = 0:X = 0:Y = 0
    2360  REM **DEDICATED REALS**
    2370 SL = 1: REM PRINTER SLOT
    2380 RF = 0: REM REVERSE LINEFEED FLAG
    2390 R = 1: REM ROW
    2400 C = 1: REM COLUMN
    2410 LM = 5: REM LEFT MARGIN
    2420 RM = 75: REM RIGHT MARGIN
    2430 LL = 0: REM LINE LENGTH
    2440 M = 38144: REM START OF TEXT BUFFER
    2450 H = 1403: REM HORZ POSITION
    2460 SP = 1: REM DEFAULT LINE SPACING
    2470  REM **STRING EQUIVALENTS**
    2480 X$ = ""
    2490 V$ =  CHR$ (252)
    2500 U$ =  CHR$ (95)
    2510 D$ =  CHR$ (4)
    2520 CL$ =  CHR$ (12): REM CLEAR SCREEN
    2530 LC$ =  CHR$ (29): REM CLEAR LINE
    2540 BS$ =  CHR$ (8): REM BACKSPACE
    2550  REM   
    2560  REM ***TITLE***
    2570  REM   
    2580  VTAB 4: HTAB 9: PRINT "TURN ON PRINTER OR....": HTAB 6: PRINT "PRESS PRINTER 'SELECT' BUTTON."
    2590  PRINT D$;"PR#1": PRINT 
    2600  HOME : POKE 1912,0
    2610  PRINT D$;"PR#3": PRINT CL$
    2620 A$ = "TYPEWRITER"
    2630 CL =  - 16336: SPEED= 150
    2640  VTAB 6: POKE H,31: FOR I = 1 TO 10: PRINT  MID$ (A$,I,1) + " ";:X =  PEEK (CL) +  PEEK (CL) +  PEEK (CL) +  PEEK (CL) +  PEEK (CL): NEXT 
    2650  SPEED= 255
    2660  PRINT : VTAB 10: POKE H,32: PRINT "BY JAMES D EVANS"
    2670  VTAB 14: POKE H,24: PRINT "COPYRIGHT 1988 BY MICROSPARC, INC."
    2680  VTAB 16: POKE H,27: PRINT "* PRESS <RETURN> TO BEGIN *";
    2690  POKE  - 16368,0: WAIT  - 16384,128: POKE  - 16368,0
    2700  RETURN 
    2710  REM 
    2720  REM ***ERROR TRAP***
    2730  REM 
    2740  POKE 216,0:EC =  PEEK (222):LN =  PEEK (218) +  PEEK (219) * 256: CALL 54915
    2750  PRINT : VTAB 10
    2760  IF EC = 4 THEN  PRINT "DISK IS WRITE-PROTECTED -- PLEASE REMOVE TAB FROM NOTCH ";: GOTO 2830
    2770  IF EC = 8 THEN  PRINT "DISK I/O ERROR -- PLEASE CHECK DISK AND DRIVE ";: GOTO 2830
    2780  IF EC = 9 THEN  PRINT "DISK IS FULL -- PLEASE INSERT A DIFFERENT DISK ";: GOTO 2830
    2790  IF EC = 10 THEN  PRINT "FILE LOCKED -- PLEASE THINK OF A DIFFERENT FILE NAME ";: GOTO 2830
    2800  IF EC = 11 THEN  PRINT "ILLEGAL FILE NAME -- PLEASE THINK OF A DIFFERENT NAME ";: GOTO 2830
    2810  IF EC = 255 THEN  PRINT "<CTRL-C> IS NOT AN ACCEPTABLE KEYSTROKE -- PLEASE NOTE ";: GOTO 2830
    2820  PRINT "ERROR #";EC;" HAS OCCURRED IN LINE ";LN;" -- PLEASE NOTE ";
    2830  PRINT "AND HIT <RETURN> ->";
    2840  GOSUB 170: IF A$ <  >  CHR$ (13) THEN  GOTO 2840
    2850  PRINT : VTAB 10: PRINT LC$: ONERR  GOTO 2740
    2860  GOTO 260
    2870  GET A$: IF A$ <  > "Y" AND A$ <  > "N" AND A$ <  > "y" AND A$ <  > "n" THEN 2870
    2880  RETURN 
    
  • tiny-c Reference Manual Excerpt

    tiny-c Reference Manual Excerpt

    The project found this little manual instructive. You could say it is a kind of C flavour that is inspired by BASIC!

    https://archive.org/details/tiny-c_manual

    Preface

    The sources of ideas that went into tiny-c are many. First there is BASIC [Kemeny & Kurtz 1967]. BASIC has become the de facto standard training language in the United States. It industry, is popular in high schools, universities, even in where it is used for some production work. Although BASIC has its faults, its one big strength is that it is easy to learn. This is largely because it offers a single computing environment. You can enter new program lines, change old ones, and start a program running all from one command environment. You do not have to remember the environment you are in, i.e., you edit mode, compile mode, link mode, system mode, run mode, etc., when giving a command. There are no commands to shift from mode to mode. There no relocatable object modules, link editors, and all the other paraphernalia of “real” computers. Is is very simple and very adequate. Thus a focus is made on the essential elements of computing, as opposed to the elements of “wrestling” with a computer.

    The LOGO language [Feurzeig 1975] is in many ways similar to tiny-c. It offers a well-structured language based on BASIC, as well as a single environment for programming and execution. LOGO was used experimentally in public schools with very young children. The experiment showed that children could grasp simple computer concepts and work through a prepared set of exercises, and then do creative work of their own.

    C [Ritchie, Kernighan, & Lesk 1975] is a computer language designed by Dennis Ritchie, at Bell Telephone Laboratories, tiny-c borrows its overall structure from C. C is broadly used in universities and in industry. It has been used to program a very advanced and powerful computer operating system, called UNIX [Ritchie & Thompson 1974]. At yet it is a very simple language. C has no native input/output, e.g., read or print statements. Input/output is done using functions. Thus C concentrates on COMPUTING facilities, and allows external development or elaborations of input/output. tiny-c has adopted this idea.

    The command environment for tiny-c is written in tiny-c. It needs no translation to the micro-processor’s machine language. This corresponds somewhat to the idea of using C as the programming language to implement UNIX. So, although intended as a training language for structured programming, tiny-c is a powerful language.

    The tiny-c OWNER’S MANUAL is trying to reach four audiences at the same time. For those new to structured programming we have a brief tutorial and program walk-through so they can get the gist of it without getting bogged down in details. Experienced users of structured programming will find that the references sections let them quickly discover the features of tiny-c. For those who want to know how the tiny-c interpreter works, we have described its operation. And, finally, for those who want to install tiny-c on their home computer, we have included a complete installation guide.

    Introduction

    What is tiny-c? tiny-c is

    • a language, plus
    • a standard library, plus
    • a program preparation system.

    Without any other software aids, you can prepare tiny-c programs, run them, edit them, store them on a cassette or floppy disk, and read them back later.

    tiny-c is a structured programming language which has if-then-else, while-loops, functions, global and local variables, and character and integer data types, pointers, and arrays.

    tiny-c is independent of operating systems. You can interface it easily to the input/output routines on your computer.

    tiny-c can invoke your own machine language subroutines so the tiny-c programming language can be fitted to your system and your system can be reflected in and extend the language.

    A tiny-c Program Walk-Through

    Figure 1-1 is a complete tiny-c program consisting of two functions.

    FIGURE 1-1

    /* guess a number between 1 and 100
    /* T. A. Gibson, 11/29/76
    
    guessnum [
        int guess, number
        number = random (1,100)
        pl "guess a number between 1 and 100"
        pl "type in your guess now"
        while (guess != number) [
            guess = gn
            if (guess == number) pl "right !!"
            if (guess > number) pl "too high"
            if (guess < number) pl "too low"
            pl""; pl""
        ] /* end of game loop
    ]     /* end of program
    
    /*
    /* random-generates a random number
    
    int seed, last /* globals used by random
    random int little, big [
        int range
        if (seed == 0) seed = last = 99
        range = big - little + 1
        last = last * seed
        if (last < 0) last = -last
        return little + (last/8) % range
    ]

    End of FIGURE 1-1

    How does this program work? Let’s do a program walk-through:

    Starting at the top, the first two lines are COMMENTS. A comment start with /* and goes to the end of the line.

    guessnum” is the name of a FUNCTION which is called to start the program.

    Following “guessnum” is a COMPOUND STATEMENT, which is 12 lines long, the last line being:

    ]     /* end of program

    A compound statement is everything between balanced left-right brackets.

    The first SIMPLE STATEMENT in guessnum is:

    int guess, number

    This declares two INTEGER VARIABLES named “guess” and “number”. All variables in tiny-c must be declared. When executed, the int statement will create the variables, and given them an initial value of zero.

    The second simple statement in guessnum is

    number = random (1,100)

    This sets number equal to the value of the tiny-c program function random executed with its first ARGUMENT equal to 1 and its second argument equal to 100. In our program the function random returns a random number between 1 and 100.

    On the next line, pl is a tiny-c LIBRARY FUNCTION which prints a line. In prints the quoted string which is its argument.

    while sets up a LOOP. The general form of while is:

    while (expression) statement

    In this instance, the EXPRESSION part is

    guess != number

    where != means not equal to. This expression is evaluated, and if it is true, the statement is done, and then the expression is evaluated again. If it is false, the statement is skipped. Initially, guess is 0 and number cannot be less than `, so the expression is initially true. Therefore the statement is executed.

    The statement is compound, and is composed of six simple statements. The first of these statements is

    guess = gn

    gn, which stands for “get number” is another standard library function. It reads a number types in by the user at the terminal, and returns that value. So here the program waits until the user types a number and a carriage return, and then guess is assigned the number typed.

    The next three simple statements are if statements. The general form of the if statement used here is

    if (expression) statement

    where statement is executed if the expression is true.

    Statements five and six of the while’s compound statement are pl"". pl"" goes to a new line, and prints nothing. The semicolon allows you to write more than one simple statement on the same program line. So

    pl"" ; pl""

    prints two blank lines.

    Now we are at the end of the while loop. Since the expression part of the while was true, the while statement is executed again. This starts with another evaluation of the expression to see if it is true or false. If the first guess is not equal to number, the compound statement is executed again. Another guess is read, the appropriate remark is made, and two more blank lines are printed; the while is done yet again. Eventually, the user gets the right number and guess is equal to number. This will cause a “right!!” and two blank lines to be printed. The while condition is then tested again. The expression guess != number is evaluated and found to be false, so the entire compound statement of the while is skipped, which brings us to the end of guessnum. The game is over. The program stops because the end (the last ]) of guessnum is reached.

    Before we walk through random, notice the integers seed and last are declared outside of both guessnum and random. They are called GLOBAL VARIABLES. They will be created once when the program is started. They are initially zero, and are known and usable by both guessnum and random. On the other hand, guess, number, and range are LOCAL VARIABLES. guess and number are known and usable only within guessnum, while range is local to random.

    The first line of random gives the function name. And, before the [, it declares two integer arguments, little and big. A VALUE must be supplied for each argument when a function is called. The call in the sixth line of guessnum sets little to 1, and big to 100. Now we enter the BODY of the function random.

    range is declared an integer and is initially zero. On the first call, seed is zero. Now seed and last are both set to 99. range is calculated, and is 100. last is set to the product of the last and seed which is 9801. This is not less than 0, so the statement part of the if is not evaluated.

    We next come to the return statement. It does two things. First, it evaluates the expression. The result is made the VALUE OF THE FUNCTION. Second, it returns control to the program that called the function. tiny-c expressions are similar to algebraic expressions. The symbol + means add, / means divide, and - means subtract (or take the negative). To indicate multiplication, a * is used. An unusual symbol is %, which means divide the left side by the right side and take the REMAINDER (not the quotient). So, for example,

    1225 % 100

    is 25.

    Thus the return statement calculates the expression:

    little + (last/8) % range
    
    = 1 + (9801/8) remainder 100
    
    = 1 + 1225 remainder 100
    
    = 1 + 25
    
    = 26

    The value 26 is returned as the value of function random. It also leaves 9801 in last, and 99 in seed. Since these are global variables, their values are retained between function calls. This is not true of local variables like range. Their values are retained only during the execution of the function in which they are defined. When that function is left their values are lost.

    On a second call to random, range is recreated, and reinitialised to zero. seed is not zero, so seed and last are not set to 99, but remain 99 and 9801 respectively. range is recalculated as 100. Then

    last = last * seed
    
         = 9801 * 99
         
         = 970299

    This number is too big for tiny-c. Any computer has a limit on the size of the numbers that can be computed. tiny-c numbers must be in the range

    -32768 <= number <= 32767.

    last OVERFLOWS this range. It will be assigned the value -12741! (We explain this more completely in Section 2.11.) This is less than 0, so the next statement assigns last the value 12741. Then the return statement calculates:

      1 + (12741/8) remainder 100
    
    = 1 + 1592 remainder 100
    
    = 93

    This is returned as the second value of random.

    REVIEW OF THE WALK-THROUGH

    The purpose of the walk-through is to get a feeling for programming in tiny-c. We have seen that

    • A tiny-c program is a set of functions.
    • Some functions are standard library functions, line gn and pl.
    • Global variables stay around and hold their values. Local variables come and go.
    • Function and variable names can be as long as you want.
    • A group of statements enclosed in brackets makes a compound statement which can be treated just like a simple statement.

    Structured Programming – What tiny-c Is All About

    Perhaps you have heard structured programming described as “go-to-less” programming. Or programming with just if-then-else and do-while control statements. Such remarks oversimplify what structured programming is all about. The essence of structured programming is PROGRAM CLARITY. You can write programs in small, modular parts, with easy-to-follow program flow. You can use well-chosen, descriptive variable names. This leads to clear, understandable programs. Program clarity is what structured programming is all about.

    We discuss here four principle ideas that make program clarity possible. These are: modularity, predictable program flow, local variables, and the simple idea of meaningful variable names.

    MODULARITY in software is just as important as modularity in hardware. It makes it humanly possible to deal with complexity. A module is a brick or atom used for building bigger modules. Seen from within, a module may be very complex but from the outside it is an indivisible whole. Software modularity is achieved through the use of FUNCTIONS.

    PROGRAM FLOW is predictable if you can point to any statement and easily answer the question “under what conditions is this statement executed?” This is particularly important if the program is 20 or 30 pages long, and still has bugs. Scanning the whole program and drawing arrows is no fair. That’s not considered an easy way to answer the question. Predictable program flow can be achieved in many ways. In tiny-c, it is done with COMPOUND STATEMENTS.

    Compound Statements

    Functions also make it possible to hide variables used in a strictly local context. The variable n is very popular; it’s used frequently to count things. Have you ever had a program blow up because you were using n in two places for two purposes? The fix was to change one of them to n1. A better idea is in the concept of LOCAL and GLOBAL variables.

    As for long, MEANINGFUL NAMES for variables and functions — just look at the sample programs to see the improvement.

    David Gries suggests structured programming be called “simplicity theory”, and characterizes it as “an approach to understanding the complete programming process” [Gries 1974]. As a pleasant dividend, structured programming is more enjoyable than monolithic programming. It should certainly, therefore, be a part of personal computing. To begin our look at tiny-c as a structured programming language, let’s look at the foundation of functions and predictable program flow — the compound statement.

    When you write a program, you write a list of statements:

    x = x-1 
    a = b+c 
    b = b*2-c 
    x = b-a 

    The idea behind a compound statement is to make one statement – a molecule – out of a set of statements – some atoms. This is done in tiny-c by

    [x = x-1 
     a - b+c 
     b = b*2-c 
     x = b-a] 

    Anywhere you can write a simple statement you can also write a compound statement. This sounds simple, but the effect is powerful. For example most programming languages have an if statement similar to this:

    if (logical expression) statement 

    So you can write

    if (x>0) x = x-1 

    But make the statement part compound, and you have this capability:

    if (x>0) [ 
        b = b*2-c 
        a = b+c 
        X = x-1 
    ] 

    This multiline if is not some special kind of if. It is still:

    if (logical expression) statement

    But the statement part is compound. The compound statement is treated as an indivisible unit. It is either all done or all not done depending on the value of the logical expression.

    The compound statement also is a natural for LOOPS. There is a big difference among the various programming languages in how you write loops, but they all have one thing in common. A loop has a beginning and an end. A compound statement can be used to express this. The looping statement is:

    while (logical expression) statement

    Notice the similarity with the if. Only the keyword has changed. Here’s how while works. The logical expression is evaluated. If it is true, then the statement is executed, and then the while is done again. The effect is a repeated if, i.e., a loop. As long as the logical expression remains true, the statement is done again and again. Eventually something in the statement causes the logical expression to become false, and the loop terminates. Of course, the statement can be compound, as in:

    while (x>0) [ 
        a = b+c 
        b = b*2-c 
        x = x-1 
    ] 

    The compound statement is a natural way to delimit the beginning and end of loops.

    With one simple idea, the compound statement, two things are achieved. The if statement is more powerful than is common in non-structured programming languages. The concept of a loop collapses to a simple repeated if or while statement. In both situations you are stating conditions under which the statement — whether simple or compound – is to be executed.

    Nesting Compound Statements

    ANYWHERE YOU CAN WRITE A SIMPLE STATEMENT, YOU CAN WRITE A COMPOUND STATEMENT.

    That is a fundamental rule. A compound statement contains simple statements. Therefore a compound statement can contain compound statements. Figure 1-2 illustrates this.

    FIGURE 1-2

    [ x = x-1
      a = b*c
      b = b*2-a
      x = b-a

    a=b+c is a simple statement. The rule says a compound statement can be written here. For example:

    [ x = x-1 
        [ a=b+c 
          w = y+2*x+w 
          y = 17 
        ] 
      b = b*2-a 
      x = b-a 
    ] 

    End of FIGURE 1-2

    The substitution of a compound for a simple shown in Figure 1-2 is certainly allowable, but is of no practical value.

    The real utility in nested compounds is in writing nested if and while statements. Figure 1-3 is therefore a more realistic example of the use of compound statements.

    FIGURE 1-3

    if (x>0) [ 
        while (x<limit) [
            if (case==1) [
                y = 0; w = 99
            ]
            if (case==2) [ 
                y = 99; w = 0
            ] 
            nextaction 
            x = x+1 
        ] 
    
    ] 

    End of FIGURE 1-3

    In Figure 1-3, if you remove everything except the brackets, you have this:

    [ [ [ ] [ ] ] ] 

    This is what is meant by compound statements. Brackets are used to form program units the same way parentheses are used to create arithmetic statements. The main difference is that a pair of brackets is preceded by a function name, or a logical expression. In the first case you’re naming the contents of the brackets and in the second you’re stating the conditions under which the contents are to be executed.

    Readable Program Flow

    In Figure 1-3, look at the “y=0” in the fourth line. How can it be reached? Only if case is 1, and x is less than limit. No go-to can lead here, either accidentally or on purpose.

    How can “nextaction” be reached? Only if x is less than limit, and then only after possible changes to y and w. This program has simple, predictable flow. The only way a statement other than a while can be reached is from directly above, whiles can also be reached from their matching ] below.

    Indenting and the Placement of Brackets in Compound Statements

    The brackets alone define the “structure” of a program. Indenting means nothing. But one of the purposes of structured programming is to make programs more readable and, hence, more understandable. A good choice of indenting style is very important to program readability. There are several styles to choose from. The actual choice is not too important. But once you choose a style, stick to it. Consistency IS important.

    One easily explained style is to align matching brackets vertically. This looks like:

    if (x<0) 
    [   statement 
        statement 
            "
            "
            "
    ] 

    A problem with this is that when editing the first statement, care must be taken to keep the [ intact. So some use this style:

    if (x<0) 
    [ 
    
        statement 
        statement 
            "
            "
            "
    ] 

    This takes an extra line. Also there is a visual break between the if and its statements. So some take the left bracket and move it to the end of the preceding line:

    if (x<0) [ 
        statement
        statement 
            "
            "
            "
    ] 

    The right bracket is now vertically aligned with the if or while that preceded the compound statement.

    You may pick one of these, or invent a style of your own. But, we repeat, whatever you decide to do, do it consistently.

    Functions

    A large software project can usually be broken into natural parts, and each part programmed and debugged as a separate unit. Each of these units then becomes a reliable building block for the construction of still larger parts of the project. Sometimes units can be designed to be useful in many projects.

    In various programming languages these building blocks are called subprograms, subroutines, or, as in tiny-c, FUNCTIONS. Here is a tiny-c function for any computer versus human game:

    game [ 
        getready 
        while ( stillplaying ()) [ 
           humanturn 
           if (stillplaying ()) computerturn 
        ] 
        gameover 
    ] 

    The name of the function is “game”. The compound statement that follows is called the body of the function. Each [ can be read as “do all of this”, and its matching ] read as “end of this”, game divides the design of a game program into five parts:

    getready (which initializes things, and 
              prints instructions if 
              requested), 
    
    stillplaying (which determines if the 
                  game is still going, and 
                  returns true if it is, 
                  otherwise false), 
    
    humanturn (which conducts the human's 
               turn), 
    
    computerturn (which conducts the 
                  computer's turn) , 
    
    gameover (which computes and prints 
              scores, makes remarks about 
              the human's skill, promotes 
              the human, or whatever). 

    The game function is the first step in divide-and-conquer or top-down program development. Let’s carry this development one step further. The getready function can be expanded this way :

    getready [ 
        ps "Do you want instructions?" 
        if (gc()=='y') instructions 
        setupboard 
    ] 

    getready divides the initialization into two parts: instructions, and setupboard.

    (Note: ps prints a character string, gc() reads a character, and == 'y' tests if the character is a y.)

    Notice that both game and getready are universal. They can be used in many game programs. Programming in this fashion eventually leads to a library of useful, general purpose functions. These can be pulled off the shelf into a software project. You know they work because they were used before. Your programming becomes more productive, and more pleasant.

    The next time you’re programming a sizable project, i.e., anything more than a page, try to identify subsets of the logic usable in other projects. Capture these as functions. It is gratifying to discover a general purpose function where none was suspected.

    Local and Global Variables

    A LOCAL VARIABLE is one that is known only inside a function. It can be used and changed only within the body of the function. Even its name is unknown outside the function. In fact, its name can be used in other functions without conflict. This is what makes local variables useful.

    Take a look at Figure 1-4. There are four local variables in these two functions. The variables n and maximum are local to a function. The variables n and total are local to another function. If either of these functions calls the other, the values of n will not be confused since they only have meaning inside the body of their own functions. It helps to think of local variable names as being preceded by the possessive form of the function to which they are local. For example, a function’s n and another function’s n.

    FIGURE 1-4

    afunction [ 
        int n, maximum 
        n=0 
        while (n<maximum) [ 
              .
              .
              .
            n=n+l 
        ] 
    ] 
    
    anotherfunction [
        int n, total 
              .
              .
              .
        n = n+2 
        total = total+n 
              .
              .
              .
    ] 

    End of FIGURE 1-4

    The value of locals is obvious to anyone who has spent a nasty debugging session trying to find out where, in a huge program, some variable is getting changed.

    Of course not all variables can be local. Some must be shared by many functions. These are called GLOBALS. They should be used infrequently, as they do cause debugging headaches. Choosing good, descriptive names for globals alleviates the problem, . A global named “k” is inviting disaster. Call it “klingonsleft” and you’re less likely to accidentally use it for two purposes. Also you’ve given a reader of your program a pretty good clue to the variable’s use.

    Summary – And Where We Go From Here

    We’ve walked through a simple program to get a feel for tiny-c, and we’ve discussed the virtues of structured programming. These are just the preliminaries. Now it’s time for the main events. First, a complete definition of the tiny-c language. Chapter II is devoted to this task. To prepare programs you need an editor and way of debugging. The Program Preparation System (PPS) is described in Chapter III. Examples are excellent learning tools: Chapter IV has several example programs. Maybe you want to make it bigger, better, or faster? Chapter V explains how tiny-c works. Finally, of course you’ll want to get tiny-c up and running on your own computer. Chapters VI and VII explain how to install tiny-c on an 8080 or PDP-11.

  • GOBLINS.BAS Live Coding Session

    GOBLINS.BAS Live Coding Session


    “Coding done quick”.

    I sped a ~1 hour stream up by 400% and this is what I got.

    This game was published as a type-in pamphlet here.

    You can also download the finished game here.

    Original blog post here.


    mailto:vidak@member.fsf.org

    https://matrix.to/#/@vidak:solarpunk.au

    https://retro.social/@permacomputer


    Jan 2026.

  • A Simple Guide to Porting Your BASIC

    A Simple Guide to Porting Your BASIC

    You may have considered porting some BASIC code from one dialect to another.

    Do not be dissuaded, the process can sometimes be rewarding.

    When porting on BASIC to another, I have found the following guides to be useful:

    Strip out all lines with references to POKE and PEEK.

    This is my preferred strategy. Almost every system addresses memory differently, and has a different memory map.

    Check the way arrays work on your target machine. Especially string arrays.

    Many systems will allow simple string arrays, such as: S$(100)

    But how long are these strings? How does the machine assign and evaluate each index? Some machines may even accept two-dimensional string arrays.

    Every application will make use of some subset, and not every single feature of it’s machine’s arrays, so don’t be daunted. Sometimes the job can be done with very little modification.

    INPUT statements may be an issue. Some parse input differently.

    Does you machine have LINE INPUT, or just INPUT?

    INPUT splits the input into multiple variables on commas in the input, whereas LINE INPUT puts the entire line into one variable.

    File operations like OPEN and CLOSE will accept different arguments.

    This can be quite tricky.

    Since you have made it this far into the blog post, please consider the following table of conversions between my most used BASICS:

    DartmouthAPPLESOFTATARI 8-BITBBC BASICCOMMODORE BASIC V2
    OPENFILE #file, “filenameOPEN filenameOPEN #fileno,mode control code,filenamevar = OPENIN, var = OPENOUTOPEN #exp, fileno, mode, “filename”
    CLOSECLOSE “filenameCLOSE #fileno, #filenoCLOSE #fileno; CLOSE #0 (all files)CLOSE #fileno
    LOADLOAD filenameLOAD “disk:filenameLOAD “filenameLOAD “filename“,8,[disk]
    PRINTPRINT #file, record, …PRINT exp, exp, …PRINT #fileno, record, record, …PRINT #filename, record, record, …PRINT #fileno, record, record, …
    INPUTINPUT #file, record, …INPUT [string,] var, var, …INPUT #[file,disk] varINPUT #filename, record, record, …INPUT “string” var, var, …

    Is your BASIC indexed from one (1) or zero (0)?

    Because this is an easy one. Convert every index accordingly:

    (e.g.) DIM A(255) -> DIM A(256)
    
    (e.g.) FOR I=0 TO 255 -> FOR I=1 TO 256
  • Watch Me Code A Procedurally Generated Game in BASIC!

    Watch Me Code A Procedurally Generated Game in BASIC!

    “Coding done quick”.

    I sped a ~2 hour stream up by 800% and cut some boring bits out, and this is what i got.

    Experimenting with a large, procedurally generated world.

    mailto:vidak@member.fsf.org

    https://matrix.to/#/@vidak:solarpunk.au

    https://retro.social/@permacomputer

    jan 2026

    https://sr.ht/~vidak/oats-for-my-goats

    https://basiclang.solarpunk.au/d/6-game-oats-for-my-goats

  • Scriptor: An Atari Word Processor

    Scriptor: An Atari Word Processor

    Charles Brannon – Editorial Assistant

    Scriptor is an easy-to-use, full-scrolling, character-oriented, multi-function word processor, requiring an Atari 400/800 with a minimum of 32K of memory (40K recommended), an Epson MX-80 or Atari 825 printer, and an Atari disk drive. It is programmed in both BASIC and machine language. For instructions on typing in the program, see the section under: Typing It In.

    Through The Ruby

    Computers don’t just calculate with numbers – they can also work with text. Five inch disks can replace stacks of files. Computers can sort, search, select, and update any kind of information. They can focus information. In this sense, the computer is like the ruby crystal in a laser. Ordinary random light waves are transformed and concentrated through the ruby into a tight, powerful beam. Computers can do the same for information.

    Word Processing

    Electronic text is more “liquid”, easier to work with, than words solidified on paper (hard copy). This is what makes word processing special: the extraordinary editing power it gives you. Distinctions between a rough draft and a final draft are meaningless; the work is typed, changed dynamically, and stored to disk. It can then later be recalled, revised, and printed out. Very little retyping is necessary. What a boon for anyone who writes.

    Converts to word processing immediately notice an improvement in their writing. The entire manuscript becomes “alive”, not committed to paper. Changing a word or a sentence, inserting a line or a paragraph are all accomplished with ease. For example, take just one key, the backspace key (called RUBOUT on some computers or terminals). When this key is struck, the last character typed is erased from the screen. Compare this to the frequently elaborate typewriter correction schemes.

    Besides the disk file, which has already been mentioned and which will be explained in greater detail later, an important concept in word processing is the cursor. Named after the clear plastic slide on a slide rule, the cursor shows you where the next character you type is going to appear. It usually looks like an underline, “__“, or a solid square. Users familiar with any computer have already encountered the cursor. The computer itself doesn’t need a cursor; but since you can type anywhere on the screen, the cursor is vital so that you can know where you”are”.

    The cursor can be moved up, down, left, and right with special keys, usually with arrows on them. To correct the following line:

    The quick brown dox jumped[]

    you would either press backspace ten times, erasing the text as you go, or press cursor-left ten times. The cursor moves “over” the characters without erasing them. It is then resting on the “d”:

    The quick brown [d]ox jumped

    You can correct the error by typing “f”, which overstrikes (replaces) the “d.”

    The quick brown f[o]x jumped

    The cursor can then be moved to the end of the line (ten cursor-rights), and typing resumed.

    This sounds harder than it really is. Cursor editing becomes second nature after only hours of use. The cursor UP/DOWN keys can reach lines of text above and below the current line. It is like rolling a typewriter’s platen up or down, but with one important difference – the “paper” is one continuous, long sheet.

    Getting Specific

    Two very special functions are insert and delete. Insert lets you add text in the middle of a line, by pressing INSERT to insert spaces in the text, and then typing in the word. For example;

    To be or to be, that is the question.[]

    The cursor is placed on the second “to,” and INSERT is pressed four times (three for “n-o-t,” and one for a space):

    To be or []   to be, that is
       the question.

    The word “not” is then typed:

    To be or not[]to be, that is
       the question.

    Delete is used to erase text. As distinguished from mere backspacing or spacing over a word, delete closes up the space after the deleted word:

    Take out a word[]
    1. Take [o]ut a word

    (cursor is moved to “o”)

    1. Take [u]t a word

    (DELETE typed; “a” disappears, “ut a word” moves left.)

    Take [a] word

    (DELETE is typed four times.)

    Insert and delete can also act on words, sentences, lines, or entire paragraphs in a similar way.

    Disk Files

    A “file” is simply a permanent record of your text. When the computer’s power is turned off, it forgets everything except what is “burned” (in ROM memory) into it permanently. Your text is obviously not “burned in,” or you couldn’t ever change it. If you have a blackout, or a fuse blows, say good-bye to your text.

    Catastrophes aside, you certainly don’t want to leave your computer on all the time, or keep the computer tied up with your text forever. Fortunately, you can save your text on disk, ready for any later revisions. You can type it one time, save your text, and print it out when convenient.

    Since a disk can store more than one document (unless it’s very long), you and the computer must have some way to distinguish and separate one file from another. This is usually done via a directory, a list of file names. You access a file by giving the computer the file’s name.

    “Scriptor,” the word processor program at the end of this article, has many features usually found only in professional word processors, but it lacks a few features such as search and replace, justification, data base merge, etc. Also, it is written in BASIC, so it can be rather slow at times. It is, however, aided by several machine language subroutines for time-critical situations such as disk input/output and some editing features.

    Typing It In

    Program 1 is the Scriptor program itself. Type it carefully, since it contains many critical machine language DATA statements. Extra time spent in typing it in will reward you with a smoother, bug-free word processor. Remember to use the COMPUTE! Listing Conventions (see Typing In COMPUTE’s Programs, published every issue). Use the Atari logo key to enter inverse video.

    To give you more memory for text, Scriptor deletes a substantial portion of itself after it initializes (sets up). Don’t worry – the program is busy running while the screen flashes; it just takes a while. The set-up lines from 5000-6999 are automatically erased.

    It you quit the program and try to run it again, the program will automatically try to re-RUN itself anew from disk. If you’ve changed disks, you’ll need to reload it yourself. You should SAVE the program with the filename “D:SCRIPTOR” or change line 110 appropriately. Be sure to SAVE Scriptor after you’ve typed it, before you run it, or you will find a sizeable chunk of your typing erased when you exit. You can free up more memory for text by deleting the “help” function. Take out all lines from 1570 to 1700 and remove line 775. If you’d rather keep this handy aid, leave these lines alone.

    If you get the message “Error in DATA statements” when you run the program, you need to check your typing on the bank of machine language DATA statements at the end of the program. Also make sure you haven’t typed a letter “O” for a zero (the zero is thinner than the “O”).

    If you have an Atari 825 printer, you will need to type in the lines in Program 2. This will replace the lines used for the MX-80 with lines applicable to the 825 80 Column Printer. If you have another printer, refrain from using special characters such as underlining, and you will probably be able to get one of the sets of lines to work.

    Getting Started

    The Scriptor is a full-scrolling, character-oriented word processor. Usage of cursor control keys is similar to normal Atari editor functions, with these exceptions:

    1. is used only to force a carriage return, as at the end of a paragraph, or to print a blank line. The computer will format your line when you print it out, so just type continuously. Do not press at the end of each line. Pressing prints a back-arrow at the end of the line, and erases all text to the end of that line.
    2. Insert and Delete character (CTRL-INSERT/ CTRL-DELETE) work on whole “paragraphs.” A paragraph is a block of lines from the cursor to a “back-arrow.” If there is no back-arrow, one is assumed at the end of text. Therefore, insert and delete can be quite slow if you don’t have a back- arrow somewhere.
    3. Insert and Delete line work on the entire document. The screen will blank during this operation. This is normal and speeds up the process, as it can be slow on long documents.
    4. All TAB controls work normally, just a little slower. will clear all tab settings.
    5. will not clear the screen. It is used to erase all or part of the text. Press to erase all text. Press the Atari logo key to abort the erase function.
    6. The break key is disabled. Use to exit the program.
    7. The ESC key enters the “mini-DOS.” (See below.)
    8. The console keys are “live”; see a description of their functions later.
    9. The Atari logo key is disabled for normal typing. Within prompts, it acts as an “abort” key.

    Getting Control

    Since the Atari is not a dedicated word processor (that means it’s just not a “word processing machine” like a Lanier, but is, rather, a general-purpose computer), it does not have special keys to activate word processing functions. Instead, the combination is used. For example, to quit the program, you would hold down and press . The CTRL key stands for “Control” – it is like a special shift key. The keys are linked mnemonically (easy to remember) to the commands they stand for, such as <P> for Print Text. To get a list of the commands and what they stand for at any time, just press <CTRL-?> (hold down CTRL and press the question mark) for a HELP menu. See Table 1 for a quick-reference chart of the commands.

    Going Around The Block

    An important feature in a word processor is block move and delete. Scriptor lets you “define” a series of up to 23 lines. You can then move these lines to another place in the text with Line Dupli- cate, or delete the defined lines with (Erase: Defined lines). To define a block of lines, just place the cursor on the first line and press . A flashing arrow will appear to the left of the line. Press cursor-down, and another symbol will appear underneath. Press cursor- down until all the desired lines have an arrow to their left. Then press . If you make a mistake, just try again, or press cursor-up while defining.

    To copy these lines to another place, position the cursor at the place you want the lines to ap- pear, and press . If you haven’t defined any lines, this command will be ignored. Note that you can press this key more than once to make many copies of the lines. You may want to delete the defined lines after you move them. Press . You will see the prompt “ERASE:”. Press . The lines will be deleted, just as if you used Delete line multiple times.

    A Mini-DOS

    The ESC key activates the “mini-DOS.” It lets you look at the directory and scratch, rename, lock, or unlock files. When you press , you will see:

    [D]irectory,[L]ock,[U]nlock,[R]ename,
         [S]cratch?

    Press the appropriate key. For all except the directory, you will need to enter a file name. The cursor, a half box, will be at the top of the screen. The only editing key you can use here is backspace.

    Remember that you can abort any time before pressing by pressing the logo key. While the directory is listed, you can press again to keep the directory on the screen while you use one of the other functions. You can also press [SELECT] (see later) to save or recall a file while looking at the directory. If you get an error message at the top of the screen, check the disk and your entry and try again.

    For The Record…

    To save or recall a document, press [SELECT]. The screen will display:

    [S]ave or [R]ecall

    Press the appropriate key, enter the file name, and the document will either be stored or re- trieved. If you Recall a document, it loads starting at the line the cursor is on. This lets you add text to a document. Press START twice to home the cursor to the start of the text. If you get an error message, check to see you have the right disk, consult the DOS Manual, and try again. Remember that your file name must start with a capital letter and be followed by up to seven capital letters or numbers. You can optionally put a three-character “extension” on the file if you separate it with a period, e.g., EDITOR.DOC, DRAFT3.CGB, DUNGEON. MAP, etc. You should not enter the “D:” prefix.

    Printer A La Mode

    Different printers offer special print densities and formats such as boldface, underlining, super- and subscripts, double-width, condensed, proportional spacing, etc. To underline a word or phrase, enclose it in , In other words, <CTRL-,> is underlining on, and <CTRL-.> is underlining off. Underlining works only on the 825 printer. If you have GRAFTRAX installed in your MX-80, underlining produces italics.

    The following is an advanced technique. You can “define” up to ten special characters and print them at any spot in your text. To define a character, set up a format line (sec the discussion of format lines, below) with and enter your definitions such as “1 = 123:2 = 123:3 = 27”, etc. You can then output the CHR$ code of the defined characters by embedding a caret (“^”) in your text, followed by the number (e.g., ^ 4). If you don’t put a number after it, a caret will print; otherwise, the character associated with the number (0-9) will be output. You can also output ASCII characters from within a format line with the “as” format command. For example, “as27:as18” will activate proportional spacing on the 825 printer. Use “as27:as69” for emphasized mode on the MX-80.

    Formatting Text

    Since you are typing in the raw text, with no margins or line breaks, how does the computer print a nice formatted page? The computer assumes a left margin of five, a right margin of 75, single spacing, a page length of 66, and 50 lines to be printed per page. You can change these “default” values with a format line.

    A format line is like an embedded command line. The line starts with a “format character” to prevent the line from being printed out. To get the format character, press . You should get a right-pointed “wedge.” Then type in your commands. All commands are two lowercase letters, usually followed by a number. You can put multiple commands on the same line if you separate them with colons. For example, the following line:

    >lm10:rm70:sp2<-

    will set the left margin to ten, the right margin to 70, and line spacing to two. Here is an explanation of each formatting command. Also see Table 2 for quick reference.

    Note that n represents a number, with no space between the command and the number. No real error-checking is performed on the number.

    as n

    Send byte n to printer.

    cm:

    Comment line. You can type one screen line of comments. They will not be printed to the printer. They are just for your convenience.

    cn n

    Centering. If n = 1, then centering will be ON, and all following lines will be centered until reset by cnO. If n = 0, then centering is turned OFF.

    fp

    Forced paging. Normally, the printer will “page”, or go on to the next page, when the number of lines printed equals your lines per page (lp), which defaults to 50. Forced paging pages to the next page, regardless.

    lm n

    n = left margin, which should be less than the right margin.

    ln n

    Print n blank lines.

    lp n

    Sets lines per page to nn should be less than the page length, to allow some blank space at the bottom of each page.

    nf: filename

    Will “chain” to next specified file, permitting a document to be split up into many parts. The nf ensures that they will all print as one big file. The formatting commands carry over to each file.

    pl n

    Sets the page length, which is almost always (and defaults to) 66.

    rm n

    n = right margin, which should be less than the maximum width and greater than the left margin.

    sp n

    n = 1 single spacing, n = 2 double spacing, n = 3 triple spacing, etc.

    Start The Presses

    To print your document, press . You should see:

    PRINT: (C/F)

    To start printing, just press . The printer head should be positioned at about the start of the page. The “C/F” indicates any selected option. “C” stands for Continuous Print. You would use this option with pinfeed or roll paper. It will automatically page to the start of each sheet. If you do not select continuous print, the computer will beep at the end of each page and pause. You should put in another sheet of paper and press to continue printing.

    Note that pressing a key any other time during printing will abort the printout. The “F” option stands for Fast Printout. It will blank the screen during the printing, increasing printing speed better than 30%. Some people, however, find a blank screen disconcerting. To select one of the options, press either “C” or “F.” The appropriate letter will light up and flash. To reset the option (cancel it), press the key again. Press when you are ready to print the text.

    Customizing Scriptor

    The program is fairly well-structured, with separate sections for all functions. The control keys are executed via a branching IF/THEN “bucket brigade.” Just patch in your own command where desired. Some functions you may want to add are: block transfer (performs both block insert and block delete). Search and Replace, Insert from Disk, simple data merge, etc. Machine language programmers may want to try their hand at speeding up certain aspects of the program, such as Insert Line, Delete Line, and even Print Text.

    Some useful subroutines are:

    GOSUB 540 returns the number of lines the user has typed (not necessarily the maximum number of lines) in EOT. GOSUB 600 clears the top line of the screen and positions the cursor at the first character, ready for a message. GOSUB 460 performs error checking and adjustments on the X-Y position of the cursor. GOSUB 2650 returns an adjusted (uppercase if AL = 1, no cursor controls, etc.) character in A. GOSUB 2730 is a pseudo-INPUT routine that returns IN$. Variable MX controls the maxi- mum number of characters.

    TRAP 2170 will vector errors to an “I/O Error” message. There are two re-entry points for the editor proper: GOTO 650 which clears and “refreshes” the screen, and GOTO 680 which just adjusts the cursor and continues keyboard entry (faster).

    Primary variables are: CL – the pointer to the top line (from 0-#lines) of the screen; X – the horizontal position of the cursor 2-39; Y – the vertical position of the cursor on the screen, 1-23; TXS – the string that contains all the text and is organized in 38 character substrings, one for each line; T$ and T – “temporary variables”; A – usually a keystroke typed; SCR – the address of the screen memory origin; NL – number of defined lines; FRL – the starting line in text of the defined lines; RL – the starting line in TX$ for reserved lines (the buffer). Several constants are QO, Ql, Q23- which return 0, 1, or 23 (saves memory); L2 = 38; L = 40; B$ is 38 null (CHR$(0)) characters.

    Quick Reference

    Table 1: Editing Commands

    Control Keys

    AAdvance one screen forward
    BBack up one screen
    DDefine Lines
    FPrint Format Character
    GGo to specified line
    KClear all tab settings
    LDuplicate defined lines
    PPrint Document
    QQuit Program
    SHIFT-INSERTInsert a line
    SHIFT-DELETEDelete a line
    CTRL-INSERTInsert a space
    CTRL-DELETEDelete a character
    CLEARErase:
    A = All
    R = Remainder
    D = Defined Lines
    CAPS/LOWRUpper or lowercase
    ESCMiniDOS
    Cursor keysMoves cursor with two-way scrolling
    [OPTION]Non-destructive carriage-return
    [SELECT]Save or Recall text
    [START]“Home” cursor
    [CTRL-,]Underlining ON
    [CTRL-.]Underlining OFF
    ^xPrint special character

    Table 2: Formatting Commands

    CommandDescriptionDefault
    as nSend ASCII character n to printer.
    cm:xxxxComment line
    cn nCentering 1 = on, 0 = off0 Off
    fpForced Paging
    lm nSet left margin to n5
    ln nDo n linefeeds
    lp nSet lines per page to n50
    nf: fileLink to Next File
    pl nPage length66
    rm nSet right margin to n75
    sp nSet line spacing1 (single)

    Program 1

    100 REM SCRIPTOR WORD PROCESSOR
    110 GOTO 5000
    455 RUN "D:SCRIPTOR"
    460 PF=Q0:IF X<2 THEN X=39:Y=Y-Q1
    470 IF X>39 THEN X=2:Y=Y+Q1
    480 IF Y<Q1 THEN Y=Q1:CL=CL-Q1:PF=Q1
    490 IF Y>Q23 THEN Y=Q23:CL=CL+Q1:PF=Q1
    500 IF CL<Q0 THEN CL=Q0
    510 IF CL>(MXL-Q23) THEN CL=MXL-Q23
    520 IF PF=Q0 THEN RETURN
    530 LOC=CL*L2+Q1:T=USR(SCRZAP,ADR(TX$(LOC))):RETURN
    540 REM *** FIND END OF TEXT
    550 P=ADR(TX$):T=P+RL*L2-Q1
    560 A=USR(EDCOM,T,P,2):A=A-P
    570 LC=A:EOT=INT(A/L2)
    580 RETURN
    590 REM *** ERASE TOP LINE
    600 COLOR 32:PLOT Q1,Q0:DRAWTO L2,Q0:PLOT Q1,Q0:RETURN
    610 REM *** START OF EDITOR
    611 MXL=INT(FRE(Q0)/40)-25:RL=MXL+1
    612 DIM TX$((MXL+Q23)*L2):? CHR$(125);
    613 TX$=CHR$(Q0):TX$((MXL+Q23)*L2)=TX$:TX$(2)=TX$
    620 SCR=PEEK(88)+256*PEEK(89):POKE 559,46:POKE 842,12
    630 X=2:Y=Q1:CL=Q0:POKE 702,Q0
    640 REM *** ENTRY FOR EACH PAGE
    650 POKE 54286,192
    655 POSITION Q0,Q0:? "{7 SPACES}Scriptor Word Processor";:COLOR 32:DRAWTO L2,Q0:PLOT 32,Q0
    660 LOC=CL*L2+Q1:T=USR(SCRZP,ADR(TX$(LOC)))
    670 IF TF THEN TF=Q0:GOTO 810
    675 IF FIRST=Q0 THEN POSITION 31,Q0:? MXL;" Free";:TF=Q1:FIRST=Q1
    680 POKE 53248,X*4+44
    690 IF Y=OY THEN 740
    710 ADJOY=OY*4+16:ADJY=Y*4+16
    720 A=USR(CURSOR,PMB+ADJOY,Q0):A=USR(CURSOR,PMB,ADJY,15):OY=Y
    740 K=PEEK(53279):IF K<7 THEN 2570
    770 T=PEEK(764):IF T=255 OR T=39 OR T=154 THEN 740
    775 IF T=166 THEN POKE 764,255:GOTO 1570
    790 POKE 694,Q0:A=USR(GCHAR)
    800 IF TF THEN 650
    810 IF A<32 OR A>122 OR A=96 THEN 880
    820 A=A-32*(A<96)
    830 POKE SCR+X+L*Y,A
    840 LOC=(CL+Y-Q1)*L2+X-Q1
    850 TX$(LOC,LOC)=CHR$(A)
    860 X=X+Q1-BF:GOSUB 460
    870 BF=Q0:GOTO 680
    880 IF A<>155 THEN 910
    890 GOSUB 2640:POKE SCR+X+L*Y,94:TX$(LOC,LOC+L2-X+Q1)=B$:X=2:Y=Y+1
    900 TX$(LOC,LOC)=CHR$(94):GOSUB 460:GOTO 650
    910 IF A=6 THEN A=127:GOTO 830
    920 IF A=28 THEN Y=Y-Q1:GOSUB 460:GOTO 680
    930 IF A=29 THEN Y=Y+Q1:GOSUB 460:GOTO 680
    940 IF A=30 THEN X=X-Q1:GOSUB 460:GOTO 680
    950 IF A=96 THEN A=74:GOTO 830
    960 IF A=31 THEN X=X+Q1:GOSUB 460:GOTO 680
    970 IF A=Q0 THEN A=72:GOTO 830
    980 IF A=126 THEN X=X-Q1:GOSUB 460:A=Q0:BF=Q1:GOTO 830
    1040 IF A<>255 THEN 1070
    1050 A=USR(EDCOM,ADR(TX$((CL+Y-Q1)*L2+X-Q1)),ADR(TX$(MXL*L2+37)),Q0)
    1060 GOTO 650
    1070 IF A<>254 THEN 1100
    1080 A=USR(EDCOM,ADR(TX$((CL+Y-Q1)*L2+X-Q1)),ADR(TX$(MXL*L2+37)),Q1)
    1090 GOTO 650
    1100 IF A<>157 THEN 1160
    1110 GOSUB 590:? "Insert line";
    1120 GOSUB 540:POKE 559,Q0
    1130 FOR I=EOT+(EOT<MXL) TO CL+Y STEP -Q1:T$=TX$((I-Q1)*L2+Q1,I*L2):TX$(I*L2+Q1,I*L2+L2)=T$:NEXT I
    1140 T=(CL+Y-Q1)*L2:TX$(T+Q1,T+L2)=B$
    1150 X=2:POKE 559,46:GOTO 650
    1160 IF A=159 THEN GOSUB 590:? "Tab set at ";X-Q1:TF=Q1:TB$(X-Q1,X-Q1)="*":GOTO 740
    1170 IF A=158 THEN GOSUB 590:? "Tab cleared at ";X-Q1:TF=Q1:TB$(X-Q1)=CHR$(Q0):GOTO 740
    1180 IF A<>127 THEN 1230
    1190 IF TB$=B$ THEN GOSUB 590:? "No tabs set":TF=Q1:GOTO 740
    1200 FOR I=X TO L2:IF TB$(I,I)=CHR$(Q0) THEN NEXT I:T=L2:X=2:Y=Y+Q1:GOSUB 460:GOTO 1200
    1210     T=I:I=L2:NEXT I
    1220 X=T+Q1:GOTO 680
    1230 IF A<>156 THEN 1290
    1240 GOSUB 590:? "Delete Line";
    1250 GOSUB 540:POKE 559,Q0
    1260 FOR I=CL+Y-Q1 TO EOT:T$=TX$((I+Q1)*L2+Q1,(I+2)*L2):TX$(I*L2+Q1,I*L2+L2)=T$:NEXT I
    1270 T=EOT*L2:TX$(T+Q1,T+L2)=B$
    1280 X=2:POKE 559,46:GOTO 650
    1290 IF A=11 THEN GOSUB 590:TF=Q1:? "Clear all tabs":TB$=B$:GOTO 740
    1320 IF A<>125 THEN 1450
    1330 GOSUB 590:? "Erase: ";
    1340 GOSUB 2650
    1350 IF A=155 THEN 650
    1355 IF A<>65 THEN 1370
    1360 ? "ALL - ";:GOSUB 2540
    1365 GOTO 613
    1370 IF A<>82 THEN 1380
    1372 ? "Remainder - ";:GOSUB 2540:GOSUB 2640
    1375 TX$(LOC)=CHR$(Q0):TX$((MXL+Q23)*L2)=CHR$(Q0):TX$(LOC+Q1)=TX$(LOC):GOTO 650
    1380 IF A<>68 OR NL=-Q1 THEN 650
    1400 ? "Defined Lines - ";
    1410 GOSUB 2540:POKE 559,Q0:GOSUB 540
    1420 FOR I=FRL=-Q1 TO EOT:T$=TX$((I+NL+Q1)*L2+Q1,(I+NL+2)*L2):TX$(I*L2+Q1,I*L2+L2)=T$:NEXT I
    1430 FOR I=EOT-NL TO EOT:TX$(I*L2+Q1,I*L2+L2)=B$:NEXT I:NL=-Q1
    1440 POKE 559,46:GOTO 650
    1450 IF A<>4 THEN 1810
    1460 GOSUB 590:? "Define Lines";
    1470 FL=CL:FR=Y:FRL=FL+FR:NL=Q0
    1480 POKE SCR+1+L*(FR+NL),223
    1490 LOC=CL*L2+(FR+NL-Q1)*L2:T=RL*L2+NL*L2:T$=TX$(LOC+Q1,LOC+L2):TX$(T+Q1,T+L2)=T$
    1500 GOSUB 2650
    1510 IF A=29 AND FR+NL<22 THEN NL=NL+Q1:GOTO 1480
    1520 IF A=28 AND FR+NL>FR THEN POKE SCR+1+L*(FR+NL),Q0:NL=NL-Q1
    1530 IF A=155 THEN 1550
    1540 GOTO 1500
    1550 FOR I=Q0 TO NL:POKE SCR+1+L*(FR+I),Q0:NEXT I:GOTO 650
    1570 POKE 53248,Q0:PRINT CHR$(125):POSITION 13,Q0:? " HELP Screen "
    1580 ? "{DOWN}{TAB}{3 SPACES}Control Keys:"
    1590 ? "A=Advance Page B=Page Back"
    1595 ? "D=Define Lines F=Print form at char."
    1610 ? "K=Kill all tabs L=Line Duplicate"
    1620 ? "P=Print text{4 SPACES}Q=Quit"
    1630 ? "Atari Key=Cancel Command":?
    1635 ? "^x Print special character"
    1640 ? "{DOWN}[CLEAR] Erase:All Defined Lines":POKE 85,16:? "Remainder"
    1650 ? "[OPTION] Non-destructive CR"
    1660 ? "{DOWN}[SELECT] Filer:Recall or Save"
    1670 ? "{DOWN}[START] 'Home' cursor. Press twice to go to start of text."
    1680 ? "{DOWN}[ESC] Mini DOS"
    1700 ? "{DOWN}Press RETURN.":A=USR(GCHAR):GOTO 650
    1810 IF A<>12 THEN 1910
    1820 GOSUB 590:? "Duplicate defined lines";
    1830 IF NL<Q0 THEN 650
    1840 FOR I=Q0 TO NL
    1850     IF CL+Y+I-Q1>MXL THEN I=NL:GOTO 1900
    1860     T=RL*L2+I*L2
    1870     T2=CL*L2+(Y+I-Q1)*L2
    1880     T$=TX$(T+Q1,T+L2)
    1890     TX$(T2+Q1,T2+L2)=T$
    1900 NEXT I:Y=Y+NL+Q1:GOSUB 460:GOTO 650
    1910 IF A<>27 THEN 2400
    1920 POSITION 2,Q0:? "Directory,Lock,Unlock,Rename,Scratch?"
    1930 GOSUB 2650:J=A
    1940 IF J<>76 AND J<>85 AND J<>83 AND J<>68 AND J<>82 THEN 1930
    1950 IF J<>ASC("D") THEN 2020
    1960 ? CHR$(125):POKE 53248,Q0
    1970 TRAP 2170:OPEN #2,6,Q0,"D:*.*"
    1980 INPUT #2,T$:? T$:IF LEN (T$)<17 THEN 2000
    1990 GOTO 1980
    2000 CLOSE #2:TRAP 40000:GOSUB 590:? "Press a key...";:OK=1:GOSUB 2650:IF A=27 THEN 1920
    2010 GOTO 650
    2020 GOSUB 590:J=A
    2030 IF J=76 THEN ? " LOCK  >";:J=35
    2040 IF J=83 THEN ? "SCRATCH>";:J=33
    2050 IF J=ASC("R") THEN 2130
    2070 ? "Enter Filename:";
    2080 MX=12:AL=Q1:GOSUB 2720
    2090 T$(3)=IN$:T$(1,2)="D:":POSITION 10,Q0:? DEL$(1,15);
    2100 TRAP 2170:IF J=33 THEN POSITION 24,Q0:GOSUB 2540:COLOR 32:PLOT 24,Q0:DRAWTO 38,Q0
    2110 TRAP 2170:XIO J,#2,Q0,Q0,T$:TRAP 40000
    2120 TRAP 40000:GOTO 650
    2130 GOSUB 590:? "RENAME>Current name? ";:MX=12:GOSUB 2720:T$(3)=IN$:T$(1,2)="D:"
    2140 GOSUB 590:? "RENAME>New name? ";:MX=12:GOSUB 2720:T$(LEN(T$)+Q1)=",":T$(LEN(T$)+Q1)=IN$
    2150 TRAP 2170:XIO 32,#2,Q0,Q0,T$:TRAP 40000
    2160 GOTO 650
    2170 TRAP 2170:POKE 559,46:CLOSE #2:CLOSE #3:GOSUB 590:? CHR$(253);"I/O Error #";PEEK(195);:TF=Q1:GOTO 740
    2180 GOSUB 590:? "Save or Recall";
    2190 ICCOM=834+48:ICBAL=ICCOM+2:ICBLL=ICBAL+4:ICSTAT=835+48:REM IOCB#3
    2200 GOSUB 2650:IF A=155 THEN 1380
    2210 IC A<>ASC("S") THEN 2290
    2220 GOSUB 600:? "SAVE:{3 SPACES}File name? ";:MX=12:GOSUB 2720:T$(3)=IN$:T$(1,2)="D:":GOSUB 550
    2230 POSITION 5,0:? DEL$(1,12);"ING";
    2232 TRAP 2238:OPEN #3,4,Q0,T$:CLOSE #3:GOSUB 600:? "REPLACE:  ";IN$;" - ";:GOSUB 2540
    2233 GOSUB 600:? " REPLACING ";IN$:GOTO 2240
    2238 CLOSE #3:IF PEEK(195)<>170 THEN 2170
    2240 TRAP 2170:OPEN #3,8,Q0,T$
    2250 POKE ICCOM,11:P=ADR(TX$):POKE ICBAL+Q1,INT(P/256):POKE ICBAL,P-(INT(P/256)*256)
    2260 LN=(CL+EOT+Q1)*L2:POKE ICBLL+Q1,INT(LN/256):POKE ICBLL,LN-(INT(LN/256)*256)
    2270 A=USR(ADR(CIO$),48):ERR=PEEK(ICSTAT):POKE 195,ERR:IF ERR>1 THEN 2170
    2280 CLOSE #3:TRAP 40000:POKE 53279,Q0:GOTO 650
    2290 IF A<>ASC("R") THEN 650
    2300 LK=Q0
    2310 GOSUB 590:? "RECALL: Filename? ";:MX=12:GOSUB 2720:T$(3)=IN$:T$(1,2)="D:"
    2315 LOC=(CL+Y-Q1)*L2+Q1:TX$(LOC)=CHR$(Q0):TX$((MXL+Q23)*L2)=CHR$(Q0):TX$(LOC+Q1)=TX$(LOC)
    2320 TRAP 2170:POSITION 8,0:? DEL$(1,8);"ING";:OPEN #3,4,Q0,T$
    2330 ICCOM=834+48:ICBAL=ICCOM+2:ICBLL=ICBAL+4
    2340 POKE ICCOM,5:P=ADR(TX$((CL+Y-Q1)*L2+Q1)):POKE ICBAL+Q1,INT(P/256):POKE ICBAL,P-(INT(P/256)*256)
    2350 LN=(MXL-(CL+Y-Q1))*L2:POKE ICBLL+Q1,INT(LN/256):POKE ICBLL,LN-(INT(LN/256)*256)
    2360 A=USR(ADR(CIO$),48):ERR=PEEK(ICSTAT):POKE 195,ERR:IF ERR>1 AND ERR<>136 THEN 2170
    2370 CLOSE #3:POKE 53279,Q0:TRAP 40000:IF LK=Q0 THEN 650
    2380 CL=Q0:Y=Q1:X=2:T=USR(SCRZAP,ADR(TX$))
    2390 GOTO 2950
    2400 IF A<>17 THEN 2410
    2403 GOSUB 600:? "QUIT: ";:GOSUB 2540
    2405 POKE 53277,Q0:POKE 53248,Q0:POKE 53774,192:POKE 16,192:GRAPHICS Q0:POKE 702,64:END
    2410 IF A=16 THEN 2840
    2420 IF A=Q1 THEN CL=CL+Q23:Y=Q1:GOSUB 460:GOTO 650
    2430 IF A=2 THEN CL=CL-Q23:Y=Q1:GOSUB 460:GOTO 650
    2500 GOTO 640
    2540 ? "Are you sure?";:GOSUB 2650:IF 1-(A=121 OR A=89) THEN POP :GOTO 650
    2550 RETURN
    2570 REM ***  Handle console keys
    2580 POKE 764,130:A=USR(GCHAR):POKE 77,Q0
    2590 IF K=5 THEN 2180
    2600 IF K=3 THEN X=2:Y=Y+Q1:GOSUB 460:GOTO 680
    2610 IF K=6 AND Y=Q1 AND X=2 THEN CL=Q0:X=2:GOTO 650
    2620 IF K=6 THEN Y=Q1:X=2:GOTO 650
    2630 GOTO 740
    2640 LOC=(CL+Y-Q1)*L2+X-Q1:RETURN
    2650 T=Q0:REM GET A KEY
    2660 IF PEEK(20)>20 THEN T=Q1-T:POKE 20,Q0:POKE 755,T*2
    2665 IF OK THEN IF PEEK(53279)=5 THEN POKE 755,2:POKE 559,46:POP :POKE 764,130:A=USR(GCHAR):OK=0:GOTO 2180
    2670 IF PEEK(764)=255 THEN 2660
    2680 IF PEEK(764)=154 THEN 2660
    2690 IF PEEK(764)=39 THEN POKE 764,255:SOUND Q0,5,12,4:POP :FOR T=1 TO 5:NEXT T:SOUND Q0,Q0,Q0,Q0:GOSUB 2710:GOTO 650
    2700 TRAP 2700:A=USR(GCHAR):TRAP 40000:IF A>96 AND A<123 THEN A=A-32*AL
    2710 POKE 755,2:POKE 559,46:RETURN
    2720 REM ***  PSEUDO-INPUT
    2730 IN$=""
    2740 ? CHR$(21);CHR$(30);:GOSUB 2650:? CHR$(32);CHR(30);
    2750 IF A=155 THEN 2820
    2760 IF A=126 AND LEN(IN$)>1 THEN IN$=IN$(1,LEN(IN$)-Q1):? CHR$(A);:GOTO 2740
    2770 IF A=126 AND LEN(IN$)=Q1 THEN ? CHR$(A);:GOTO 2730
    2780 IF LEN(IN$)=MX THEN 2740
    2790 IF (A<32 OR A>90) AND A<96 OR A>122 THEN 2740
    2800 ? CHR$(A);:IN$(LEN(IN$)+Q1)=CHR$(A)
    2810 GOTO 2740
    2820 AL=Q1:IF IN$="" THEN POP :GOTO 650
    2830 RETURN
    2840 REM ***  Printer Output
    2850 GOSUB 590:? "PRINT: (C/F)"
    2860 CON=Q0:F=Q0:FOR I=Q0 TO 9:PC(I)=48+I:NEXT I
    2870 GOSUB 2650:IF A=155 THEN 2910
    2880 IF A=67 THEN CON=1-CON:POSITION 10,Q0:? CHR$(67+128*CON);:GOTO 2870
    2890 IF A=70 THEN F=1-F:POSITION 12,Q0:? CHR$(70+128*F):GOTO 2870
    2900 GOTO 2870
    2910 TRAP 2170:OPEN #2,8,Q0,"P:"
    2920 GOSUB 590:? "Printing..."
    2930 LM=5:RM=75:CN=Q0:NL=Q0
    2940 SP=1:PL=66:LP=50:C=LM
    2950 GOSUB 540:IF F=1 THEN POKE 559,Q0
    2960 FOR P=Q1 TO LC
    2970     IF PEEK(764)<255 THEN GOSUB 2650:POP :GOTO 3140
    2980     Z=ASC(TX$(P))
    2990     IF CN=Q1 AND Z<>127 THEN 3460
    3000     IF Z<62 OR (Z>96 AND Z<123) THEN 3070
    3010     IF Z=94 THEN GOSUB 3210:GOSUB 3150:GOTO 3120
    3020     IF Z=72 THEN UL=Q1:PUT #2,27:PUT #2,52:GOTO 3120
    3030     IF Z=74 THEN UL=Q0:PUT #2,27:PUT #2,53:GOTO 3120
    3040     T=ASC(TX$(P+Q1)):IF Z=62 AND T>15 AND T<26 THEN PUT #2,PC(T-16):P=P+1:GOTO 3120
    3060     IF Z=127 THEN 3230
    3070     IF C=LM THEN FOR I=Q1 TO LM:PUT #2,32:NEXT I
    3080     C=C+1
    3090     PUT #2,Z+32*(Z<64)
    3100     T=Q0:IF RM-C>=10 THEN 3110
    3105     FOR I=1 TO LEN(BRK$):IF Z+32<>ASC(BRK$(I,I)) THEN NEXT I:GOTO 3110
    3107     TT=ASC(TX$(P+Q1)):IF TT=Q0 OR TT=94 OR Z=Q0 OR Z=13 THEN I=LEN(BRK$):NEXT I:GOSUB 3150:T=Q1
    3110     IF T=Q1 AND ASC(TX$(P+Q1))=Q0 THEN P=P+Q1:IF P<LC THEN 3110
    3120 NEXT P
    3130 GOSUB 3150
    3140 PRINT #2,CLOSE #2:POKE 559,46:TRAP 40000:GOTO 650
    3150 FOR I=Q1 TO SP:PRINT #2:NEXT I
    3160 C=LM:NL=NL+SP:PRINT #2:NEXT I
    3160 C=LM:NL=NL+SP:IF CN<Q0 THEN CN=Q1
    3170 IF NL<LP THEN RETURN
    3180 IF CON=Q0 THEN FOR I=Q0 TO 255 STEP 17:SOUND Q0,255-I,Q0,15-INT(I/17):NEXT I:T=USR(GCHAR):GOTO 3200
    3190 FOR I=Q1 TO PL-LP:PRINT #2:NEXT I
    3200 NL=Q0:RETURN
    3210 REM ***  SKIP TRAILING BLANKS
    3220 T=INT(P/L2):P=(T+Q1-(P/L2=T))*L2:RETURN
    3230 REM Handle special formatting
    3240 P=P+Q1
    3250 CM$=TX$(P,P+Q1):T$=""
    3260 FOR I=P+2 TO LC
    3270     IF TX$(I,I)>=CHR$(16) AND TX$(I,I)<CHR$(26) THEN T$(LEN(T$)+Q1)=CHR$(ASC(TX$(I,I))+32):NEXT I
    3280 V=Q0:P=I:TRAP 3290:V=VAL(T$)
    3290 TRAP 2170:IF CM$="cn" THEN CN=V
    3300 IF CM$="ln" THEN FOR J=Q1 TO V:GOSUB 3150:NEXT J
    3310 IF CM$="sp" THEN SP=V
    3320 IF CM$="pl" THEN PL=V
    3330 IF CM$="lp" THEN LP=V
    3340 IF CM$="lm" AND V>0 THEN LM=V:C=V
    3350 IF CM$="rm" AND V>0 THEN RM=V
    3360 IF CM$="fp" THEN GOSUB 3180:POKE 559,46-46*F
    3370 IF CM$="as" THEN PUT #2,V
    3380 IF CM$="cm" THEN FOR I=P TO P+79:IF TX$(I,I)<>"^" THEN NEXT I:I=I-Q1
    3390 IF CM$="cm" THEN P=I+Q1:GOTO 3450
    3400 IF CM$<>"nf" THEN 3430
    3410 T$="D:":FOR I=Q0 TO 11:Z=ASC(TX$(P+I,P+I)):IF Z<>94 AND P+I<=LC THEN T$(3+I)=CHR$(Z+32*(Z<63)):NEXT I
    3415 TX$(Q1)=CHR$(Q0):TX$((MXL+Q23)*L2)=CHR$(Q0):TX$(2)=TX$
    3420 POKE 559,46:GOSUB 590:? "Printing ";T$:LK=Q1:CL=Q0:Y=Q1:GOTO 2320
    3430 IF ASC(CM$)>15 AND ASC(CM$)<26 THEN PC(ASC(CM$)-16)=V
    3440 IF TX$(P,P)<>"^" AND P<LC THEN 3240
    3450 GOSUB 3220:P=P+Q1:GOTO 2970
    3460 REM *** CENTRE STRING
    3470 LN=Q0:FOR I=P TO P+79:IF TX$(I,I)<>"^" THEN LN=LN+Q1:NEXT I
    3480 WIDTH=RM-LM:UL=Q0:IF TX$(P,P)=CHR$(72) THEN UL=Q1
    3490 FOR I=Q1 TO (WIDTH-LN)/2+LM:PUT #2,32:NEXT I
    3500 C=C+I:CN=-Q1:GOTO 2990
    5000 REM  INITIALISATION
    5010 GRAPHICS 17:SETCOLOR 4,1,10
    5020 DL=PEEK(560)+256*PEEK(561)+4:POKE DL+5,7:POKE DL+10,7:POKE DL+14,7
    5030 POSITION 6,4:? #6;"scriptor":POSITION 3,7:? #6;"WORD PROCESSOR"
    5040 ? #6:? #6;" ";CHR$(136);CHR$(227);CHR$(153);CHR$(152);CHR$(147)
    5045 ? #6:? #6;" small systems svcs";CHR$(14);
    5050 ? #6:? #6;"{3 SPACES}CHARLES BRANNON"
    5070 Q0=0:Q1=1:Q23=23:RL=MXL+Q1:SCRZAP=1680:CURSOR=1739:EDCOM=1536:AL=1:L2=38:GCHAR=1303:SND=1331
    5080 DIM T$(79),IN$(20),B$(L2),TB$(L2),CM$(2),BRK$(8),PC(9),DEL$(20),CIO$(7)
    5090 B$=CHR$(Q0):B$(L2)=B$:B$(2)=B$:DEL$=CHR$(254):DEL$(20)=DEL$:DEL$(2)=DEL$
    5100 TB$=B$:BRK$=" ,.!?;:-":CIO$="hhh":CIO$(4)=CHR$(170):CIO$(5)="LV":CIO$(7)=CHR$(228)
    5110 OPEN #1,4,Q0,"K:"
    5120 T=Q0:OY=Q0:CL=Q0:L=40:NL=-Q1
    5130 PMB=PEEK(106)-8:POKE 559,46:POKE 53248,Q0
    5140 POKE 54279,PMB:POKE 53277,3
    5150 PMB=PMB*256+512:POKE 704,56
    5160 FOR I=Q0 TO 255:POKE PMB+I,Q0:POKE 708+3*RND(Q0),PEEK(53770):NEXT I
    5180 SETCOLOR 4,8,2
    5250 FOR I=0 TO 70:READ A:POKE 1280+I,A:CHECKSUM=CHECKSUM+A:POKE 708+3*RND(Q0),PEEK(53770):NEXT I
    5290 FOR I=0 TO 247:READ A:POKE 1536+I,A:CHECKSUM=CHECKSUM+A:POKE 708+3*RND(Q0),PEEK(53770):NEXT I
    5300 IF CHECKSUM<>47765 THEN PRINT CHR$(253);"Error in DATA statements...":END
    5310 DATA 72,138,72,169,10,162,2,141,10,212,141,24,208,141,26,208,142,23,208,104,170,104,64
    5320 DATA 104,173,252,2,201,255,240,249,133,124,162,255,142,252,2,32,51,5,32,254,246,133,212,169,0,133,213,96
    5330 DATA 162,0,142,0,210,162,15,142,1,210,160,0,234,200,208,252,202,16,244,96
    5340 DATA 216,104,104,133,213,104
    5350 DATA 133,212,104,133,204,104
    5360 DATA 133,203,104,104,208,47
    5370 DATA 32,109,6,165,205,76
    5380 DATA 43,6,160,0,177,205
    5390 DATA 200,145,205,198,205,165
    5400 DATA 205,201,255,208,2,198
    5410 DATA 206,197,212,208,235,165
    5420 DATA 206,197,213,208,229,160
    5430 DATA 0,177,205,200,145,205
    5440 DATA 136,152,145,205,96,201
    5450 DATA 1,240,3,76,221,6
    5460 DATA 32,109,6,76,91,6
    5470 DATA 160,1,177,212,136,145
    5480 DATA 212,230,212,208,2,230
    5490 DATA 213,165,213,197,206,208
    5500 DATA 237,165,212,197,205,208
    5510 DATA 231,169,0,168,145,212
    5520 DATA 96,165,212,133,205,165
    5530 DATA 213,133,206,160,0,177
    5540 DATA 205,201,94,240,18,230
    5550 DATA 205,208,2,230,206,165
    5560 DATA 206,197,204,208,238,165
    5570 DATA 205,197,203,208,232,96
    5580 DATA 165,88,133,203,165,89
    5590 DATA 133,204,104,104,133,206
    5600 DATA 104,133,205,162,24,76
    5610 DATA 188,6,160,0,177,205
    5620 DATA 200,200,145,203,136,192
    5630 DATA 38,208,245,24,169,38
    5640 DATA 101,205,133,205,144,2
    5650 DATA 230,206,24,169,40,101
    5660 DATA 203,133,203,144,2,230
    5670 DATA 204,202,208,218,96,104
    5680 DATA 104,133,204,104,133,203
    5690 DATA 104,168,104,145,203,200
    5700 DATA 192,4,208,249,96,160
    5710 DATA 0,177,212,208,20,198
    5720 DATA 212,165,212,201,255,208
    5730 DATA 2,198,213,197,203,208
    5740 DATA 238,165,213,197,204,208
    5750 DATA 232,96
    6000 GRAPHICS 0:POKE 559,Q0:POKE 16,64:POKE 53774,64
    6010 FOR I=5000 TO 5900 STEP 100:? CHR$(125):POSITION 2,3:FOR J=I+90 TO I STEP -10:? J:NEXT J:? 110:? "CONT"
    6020 POKE 712,PEEK(53770):POKE 842,13:POSITION 0,0:STOP 
    6030 POKE 842,12:NEXT I
    6040 SETCOLOR 2,12,Q0:SETCOLOR 4,8,10:SETCOLOR Q1,Q0,12:POKE 752,Q1
    6050 POKE PEEK(560)+256*PEEK(561)+3,194:POKE 512,0:POKE 513,5
    6060 ? CHR$(125):? :? :FOR I=6000 TO 6060 STEP 10:? I:NEXT I:? "GOTO610":POSITION 0,0:POKE 842,13:STOP