1REM Bugs: Top left char not copied to top right (or reversed - 0,0 lost)
    2REM Fails if cursor editing
    3REM Argh! Spool file, printer etc!
    4REM And vdu 21?
    5REM Turn off cursor during swap & restore to prev state after?
   10osbyte=&FFF4
   20oswrch=&FFEE
   30REM This program reads and echoes
   40REM like a dumb typewriter.
   50REM On input of a special key, it
   60REM reverses the screen so that
   70REM arabic input will be read the
   80REM correct way round! This simple
   90REM scheme replaces ALL the daft
  100REM *commands in the Arabic rom.
  110PROCAss
  120REPEAT
  130C%=GET
  140IF C%=ASC("*") THEN PROCSwapScr ELSE VDU C%
  150IF C%=13 THEN VDU 10
  160UNTIL0
  170DEFPROCSwapScr
  180 CALL swap
  190ENDPROC
  200 
  210DEFPROCAss
  220DIM Code 511
  230FOR Pass = 4 TO 6 STEP 2
  240P%=Code:O%=Code
  250[OPT Pass
  260.swap
  270 OPT FNinit \ -> MaxX,MinX,MaxY,MinY
  280 Lda MaxY:Sec:Sbc MinY:Sta MaxYMinY
  290 Clc:Adc #1:Sta LastYP1
  300 Lda MaxX:Sec:Sbc MinX:Sta MaxXMinX
  310 Clc:Adc #1:Sta LastXP1
  320 Clc:Ror LastXP1
  330 Ldy #0
  340.YLoop
  350 Ldx #0
  360 Lda MaxXMinX
  370 Sta RightX
  380.XLoop
  390 Stx XParm:Sty YParm:Jsr RdScr \ X,Y -> A
  400 Sta LeftChar
  410 Lda RightX:Sta XParm:Jsr RdScr \ MaxX-MinX-X,Y -> A
  420 Sta RightChar
  430 Lda #31:Jsr oswrch
  440 Txa: Jsr oswrch
  450 Tya: Jsr oswrch
  460 Lda RightChar: Jsr oswrch
  470 Lda #31:Jsr oswrch
  480 Lda RightX:Jsr oswrch
  490 Tya: Jsr oswrch
  500 Lda LeftChar: Jsr oswrch
  510 Dec RightX: Inx: Cpx LastXP1:Bne XLoop
  520 Iny: Cpy LastYP1:Bne YLoop
  521 OPT FNrestore
  530 Rts
  540.MaxX EQUB 79
  550.MaxY EQUB 30
  560.MinX EQUB 0
  570.MinY EQUB 0
  580.OldX NOP
  590.OldY NOP
  600.LastXP1 NOP
  610.LastYP1 NOP
  620.MaxXMinX NOP
  630.MaxYMinY NOP
  640.LeftChar NOP
  650.RightChar NOP
  660.RightX NOP
  670.XParm NOP
  680.YParm NOP
  690.OldVDUvar NOP
  700 OPT FNrdscr
  710 OPT FNvduvar
  720]
  730NEXT Pass
  740ENDPROC
  750PROCrestore
  760ENDPROC
  770DEFFNinit
  780[OPT Pass
  790 Lda #160:Ldx #&66: Jsr osbyte \ Read VDU Variable
  800 Stx OldVDUvar
  810 Lda #23:Jsr oswrch
  820 Lda #16:Jsr oswrch
  830 Lda #1:Jsr oswrch
  840 Lda #254:Jsr oswrch
  850 Lda #134
  860 Jsr osbyte
  870 Sty OldY:Stx OldX
  880 Lda #&08:Jsr vduvar:Sta MinX
  890 Lda #&09:Jsr vduvar:Sta MaxY
  900 Lda #&0A:Jsr vduvar:Sta MaxX
  910 Lda #&0B:Jsr vduvar:Sta MinY
  920]
  930=Pass
  940 
  950DEFFNrdscr:REM (X%,Y%)
  960[OPT Pass
  970.RdScr
  980 Phx:Phy
  990 Lda #31:Jsr oswrch
 1000 Lda XParm:Jsr oswrch
 1010 Lda YParm:Jsr oswrch
 1020 Lda #135 \ Read text at cursor
 1030 Jsr osbyte
 1040 Txa
 1050 Ply:Plx
 1060 Cmp #0:Bne notweak:Lda #32:.notweak \ Cell contained graphics
 1070 Rts
 1080]
 1090=Pass
 1100DEFFNrestore
 1110[OPT Pass
 1120 Lda #23:jsr oswrch
 1130 Lda #16:jsr oswrch
 1140 Lda OldVDUvar:jsr oswrch
 1150 Lda #0:jsr oswrch:jsr oswrch:jsr oswrch:jsr oswrch:jsr oswrch:jsr oswrch:jsr oswrch:jsr oswrch:jsr oswrch
 1170 Lda #23:jsr oswrch
 1180 Lda #16:jsr oswrch
 1190 Lda #2:jsr oswrch
 1200 Lda #255:jsr oswrch
 1210 Lda #0:jsr oswrch:jsr oswrch:jsr oswrch:jsr oswrch:jsr oswrch:jsr oswrch:jsr oswrch:jsr oswrch:jsr oswrch
 1230 Lda #31:jsr oswrch
 1240 Lda OldX:jsr oswrch
 1250 Lda OldY:jsr oswrch
 1260]
 1270=Pass
 1280ENDPROC
 1290DEFFNvduvar
 1300[OPT Pass
 1310.vduvar
 1320 Phx:Pha:Lda #160:Plx:Jsr osbyte:Txa:Plx
 1330 Rts
 1340]
 1350=Pass