;ÁÃÍÅ 0.07


; --- ÃONFIGURABLE VALUES

; ÓTART ADDRESS
*=$C000; Ã64 VALUE
;*=$0C00; Ã128 VALUE

; ÏUTPUT FILE NAME
!TO "INPUTDRV64.BIN"; Ã64 FILE NAME
;!TO "INPUTDRV128.BIN"; Ã128 FILE NAME

; ÐOINTER'S MAXIMUM COORDINATES
ÍAXIMUMÃOORDINATEØ = 319; ÖÉÃ VALUE
;ÍAXIMUMÃOORDINATEØ = 639; ÖÄÃ VALUE
ÍAXIMUMÃOORDINATEÙ = 199

; ÍAXIMUM STEP SIZE ("SPEED") FOR
; JOYSTICK ACCELERATION ROUTINE, IN
; PIXELS.
ÍAXÓTEP = $10; (MAX. $7F)

; ÄISTANCE BEFORE ACCELERATION STARTS,
; IN PIXELS.
ÍAXÔIME = $04; (MAX. $7F)

; ÓPRITES TO USE FOR OVERLAY POINTER
ÓPRITE_Á = 0
ÓPRITE_Â = 1

; ÃOORDINATES OF "POINTER PIXEL" WITHIN
; POINTER SPRITES; ADJUST THESE IF YOU
; USE DIFFERENT SPRITES.
; (0,0) IS SPRITE'S UPPER LEFT PIXEL.
ÓPRITE_ÈOTSPOTØ = 1
ÓPRITE_ÈOTSPOTÙ = 1

; ÂASE OF ÖÉÃ REGISTERS TO WRITE TO.
ÖÉÃ_ÂASE = $D000; Ã64 VALUE
;ÖÉÃ_ÂASE = $11D6; Ã128 VALUE, LOCATION
; OF MIRROR REGISTERS.

; ÌOCATIONS TO STORE BUTTON STATES,
; $FF = PRESSED, $00 = NOT PRESSED.
; ÍOUSE USES BOTH BUTTONS, JOYSTICK
; ONLY USES "ÌEFTÂUTTON".
ÌEFTÂUTTON  = $A4; Ã64 VALUE
ÒIGHTÂUTTON = $A5; Ã64 VALUE
;ÌEFTÂUTTON  = $FA; Ã128 VALUE
;ÒIGHTÂUTTON = $FF; Ã128 VALUE

; ÌOCATION TO STORE POINTER'S CURRENT
; PIXEL COORDINATES. ÔHE DRIVER CODE
; RELIES ON HAVING *FOUR CONSECUTIVE*
; BYTES:
; X LOW, X HIGH, Y LOW, Y HIGH.
ÃOORDINATES = $FB; $FB-$FE

; ÌOCATION TO STORE POINTER'S CURRENT
; CHARACTER COORDINATES.
ÃHARØ = $B3; Ã64 VALUE
ÃHARÙ = $B4; Ã64 VALUE
;ÃHARØ = $9B; Ã128 VALUE
;ÃHARÙ = $9C; Ã128 VALUE


; --- ÓYSTEM CONSTANTS

; ÉNTERRUPT VECTOR
SYS_IIRQ = $0314

; É/Ï REGISTERS
SID_POT   = $D419
CIA1_PRA  = $DC00
CIA1_PRB  = $DC01
CIA1_DDRB = $DC03
;MMU_CR    = $FF00; Ã128 ONLY


; --- ÌABEL DEFINITIONS

; ÎEW NAMES FOR SOME PRECALCULATED
; VALUES, ONLY TO IMPROVE READABILITY.
; ÄON'T CHANGE THESE.
ÐOINTERØNOW = ÃOORDINATES
ÐOINTERÙNOW = ÃOORDINATES+2
ÓPRITEÁ_Ø = ÖÉÃ_ÂASE+2*ÓPRITE_Á
ÓPRITEÁ_Ù = ÖÉÃ_ÂASE+2*ÓPRITE_Á+1
ÓPRITEÂ_Ø = ÖÉÃ_ÂASE+2*ÓPRITE_Â
ÓPRITEÂ_Ù = ÖÉÃ_ÂASE+2*ÓPRITE_Â+1
ÓPRITES_ÏÆ = ÖÉÃ_ÂASE+16; Ø ÏVERFLOW
; ÔHE CHARACTER "^" IN THE FOLLOWING
; CALCULATION MEANS "TO THE POWER OF".
; ÉT IS ÁÃÍÅ SYNTAX - IF YOUR ASSEMBLER
; CANNOT DO THIS, YOU MAY WANT TO USE
; HARDCODED VALUES HERE INSTEAD OF
; CALCULATIONS.
ÓPRITES_ÂITMASK = 2^ÓPRITE_Á+2^ÓPRITE_Â
ÓPRITEÏFFSET_Ø = $18-ÓPRITE_ÈOTSPOTØ
ÓPRITEÏFFSET_Ù = $32-ÓPRITE_ÈOTSPOTÙ
; ÉN THE SPRITE COORDINATE SYSTEM, THE
; GRAPHICS PIXEL (0,0) HAS THE
; COORDINATES ($18,$32), SO THESE ARE
; NEEDED FOR CONVERTING. ÂLAME THE ÖÉÃ.


; --- ÅNTRY POINT

; ÂECAUSE THIS ROUTINE IS THE FIRST,
; THE FILE CAN BE ÂÏÏÔED ON A Ã128.
ÉNIT
; ÉNITIALISATION CODE, INSTALLS DRIVER
; ON ÉÒÑ VECTOR.
; ÆETCH ÉÒÑ VECTOR AND WRITE TO END
        LDA SYS_IIRQ
        LDX SYS_IIRQ+1
        STA MOD16+1
        STX MOD16+2
; ÌET ÉÒÑ VECTOR POINT TO DRIVER CODE
        LDA #<ÅNTRY
        LDX #>ÅNTRY
        PHP
        SEI
        STA SYS_IIRQ
        STX SYS_IIRQ+1
        PLP
; ÔHE FOLLOWING FIVE COMMANDS ARE ONLY
; NEEDED ON THE Ã128.
;       LDA MMU_CR
;       TAY
;       AND #$FE; ACTIVATE É/Ï CHIPS
;       STA MMU_CR
; ÉNIT MOUSE BUTTONS
        LDA #$11
        STA CIA1_PRB
;       STY MMU_CR; Ã128 ONLY

; ÔHE FOLLOWING THREE MINI-ROUTINES ARE
; ONLY NEEDED ON THE Ã64.

; ÃOPY SPRITES TO TAPE BUFFER
        LDX #127
ÃPÌP    LDA ÓPRITES,X
        STA $0340,X
        DEX
        BPL ÃPÌP
        LDA #ÓPRITES_ÂITMASK
; ÓET SPRITE BLOCK POINTERS
        LDX #$0D
        STX 2040+ÓPRITE_Á
        INX
        STX 2040+ÓPRITE_Â
; ÁCTIVATE POINTER SPRITES
        ORA ÖÉÃ_ÂASE+21
        STA ÖÉÃ_ÂASE+21

; ÆROM HERE ON, BOTH Ã64+Ã128 AGAIN. :)
        RTS


; --- ÖARIABLES

; ÐIXEL COUNTER BEFORE ACCELERATING
ÊOY×AITTIME !BYTE 0


; --- ÍAIN CODE

ÅNTRY
; ÔHE DRIVER CONSISTS OF SEVERAL
; DISTINCT PARTS. ÔO MINIMISE
; PERFORMANCE WASTAGE, YOU SHOULD
; REMOVE ALL PARTS YOU DON'T NEED FOR
; THE SPECIFIC APPLICATION.


; --- ÐART 0, INITIALISATIONS

; ÍAKE SURE DECIMAL MODE IS OFF
        CLD
; ÓET BUTTON STATES TO "NOT PRESSED",
; SO THE OTHER PARTS ONLY HAVE TO DEAL
; WITH SETTING THEM TO "PRESSED".
        LDA #$00
        STA ÌEFTÂUTTON
        STA ÒIGHTÂUTTON


; --- ÐART 1, HANDLING MOUSE MOVEMENTS

; MOUSE X
        LDX #$00; 0 MEANS "X STUFF"
        JSR ÐOTÄELTA
; ÎOW SIGNED X MOVEMENT IS IN Á/Ù.
; ÁDD TO CURRENT X VALUE.
        CLC
        ADC ÐOINTERØNOW
        STA ÐOINTERØNOW
        TYA
        ADC ÐOINTERØNOW+1
        STA ÐOINTERØNOW+1
; MOUSE Y
        LDX #$01; 1 MEANS "Y STUFF"
        JSR ÐOTÄELTA
; ÎOW SIGNED Y MOVEMENT IS IN Á/Ù.
; ÍOUSE AND COMPUTER USE DIFFERENT Y
; DIRECTIONS, SO DON'T ADD TO, BUT
; SUBTRACT FROM CURRENT Y VALUE.
; ÔHIS IS A REVERSE SUBTRACTION - IT
; MIGHT BE HARDER TO UNDERSTAND, BUT IT
; IS FASTER AND SMALLER THAN THE USUAL
; WAY.
        CLC
        SBC ÐOINTERÙNOW
        EOR #$FF
        STA ÐOINTERÙNOW
        TYA
        SBC ÐOINTERÙNOW+1
        EOR #$FF
        STA ÐOINTERÙNOW+1


; --- ÐART 2, HANDLING MOUSE BUTTONS

; ÐREPARE ÃÉÁ BY SETTING BITS TO INPUT
        LDY #$11
        STY CIA1_DDRB
        LDX #$FF; $FF MEANS "PRESSED"
        LDA #$10; CHECK LEFT BUTTON
        BIT CIA1_PRB
        BNE ÎOTÌÂ
        STX ÌEFTÂUTTON; STORE STATE
ÎOTÌÂ   LDA #$01; CHECK RIGHT BUTTON
        BIT CIA1_PRB
        BNE ÎOTÒÂ
        STX ÒIGHTÂUTTON; STORE STATE
; ÒESET ÃÉÁ TO NORMAL STATE
ÎOTÒÂ   LDY #$00
        STY CIA1_DDRB


; --- ÐART 3, HANDLING THE JOYSTICK

; ÆETCH BYTE HOLDING DIRECTION FLAGS
        LDA CIA1_PRA
        TAX; ...AND REMEMBER IT

; ÃHECK 'UP' DIRECTION
        ROR
        BCS DOWN
; ÓUBTRACT CURRENT STEP SIZE FROM Y
; VALUE IF NEEDED.
        TAY
        SEC
        LDA ÐOINTERÙNOW
        SBC ÊOYÓTEPSIZE
        STA ÐOINTERÙNOW
        BCS FIXÈIÕP
        DEC ÐOINTERÙNOW+1
FIXÈIÕP TYA

; ÃHECK 'DOWN' DIRECTION
DOWN    ROR
        BCS LEFT
; ÁDD CURRENT STEP SIZE TO Y VALUE IF
; NEEDED.
        TAY
        ;CLC; Ã IS ALWAYS CLEAR HERE
        LDA ÐOINTERÙNOW
        ADC ÊOYÓTEPSIZE
        STA ÐOINTERÙNOW
        BCC FIXÈIÄOWN
        INC ÐOINTERÙNOW+1
FIXÈIÄOWN       TYA

; ÃHECK 'LEFT' DIRECTION
LEFT    ROR
        BCS RIGHT
; ÓUBTRACT CURRENT STEP SIZE FROM X
; VALUE IF NEEDED.
        TAY
        SEC
        LDA ÐOINTERØNOW
        SBC ÊOYÓTEPSIZE
        STA ÐOINTERØNOW
        BCS FIXÈIÌEFT
        DEC ÐOINTERØNOW+1
FIXÈIÌEFT       TYA

; ÃHECK 'RIGHT' DIRECTION
RIGHT   ROR
        BCS ÐART3ÅND
; ÁDD CURRENT STEP SIZE TO X VALUE IF
; NEEDED.
        TAY
        ;CLC; Ã IS ALWAYS CLEAR HERE
        LDA ÐOINTERØNOW
        ADC ÊOYÓTEPSIZE
        STA ÐOINTERØNOW
        BCC FIXÈIÒIGHT
        INC ÐOINTERØNOW+1
FIXÈIÒIGHT      TYA
ÐART3ÅND


; --- ÐART 4, HANDLING JOYSTICK BUTTON

        ROR
        BCS ÐART4ÅND
        LDA #$FF; $FF MEANS "PRESSED"
        STA ÌEFTÂUTTON
ÐART4ÅND


; --- ÐART 5, JOYSTICK ACCELERATION

; ÒESTORE JOYSTICK DIRECTION BITS AND
; CHECK WHETHER TO SET SPEED TO ZERO.
        TXA
        AND #$0F; ÃLEAR UNNEEDED BITS
        CMP #$0F; ÁNY DIRECTION BIT ?
        BNE INCTEMPO
; ÎO DIRECTION WAS USED, SO RESET SPEED
; AND WAIT COUNTER TO NORMAL.
        LDA #$01
        STA ÊOYÓTEPSIZE
        LDA #ÍAXÔIME
        STA ÊOY×AITTIME
        JMP ÐART5ÅND
INCTEMPO
; Á DIRECTION BIT WAS USED, SO CHECK
; WHETHER TO ACCELERATE: ÉF SPEED IS
; ALREADY MAXIMUM SPEED, DON'T
; ACCELERATE.
ÊOYÓTEPSIZE=*+1
        LDA #$00; (SELF-MODIFYING)
; ÉF THE VARIABLE "ÊOYÓTEPSIZE" WOULD
; HAVE BEEN DEFINED AS A SEPARATE
; LOCATION (USING "!BYTE"), IT WOULD
; HAVE TAKEN A BYTE OF MEMORY. ÂY
; STORING THE VALUE INSIDE AN ÌÄÁ
; COMMAND'S ARGUMENT, WE SAVE THAT ONE
; BYTE. ÉT MIGHT MAKE A DIFFERENCE. :)
        CMP #ÍAXÓTEP; ÉF SPEED IS MAX.,
        BCS ÐART5ÅND; DON'T ACCELERATE.
; ÓPEED ISN'T MAXIMUM YET. ÃHECK
; WHETHER WE HAVE TO WAIT BEFORE
; ACCELERATING.
        DEC ÊOY×AITTIME
        BPL ÐART5ÅND
; ÃOUNTER HAS UNDERRUN, SO ACCELERATE.
        INC ÊOY×AITTIME; RESET COUNTER
        INC ÊOYÓTEPSIZE; INCREASE SPEED
ÐART5ÅND


; --- ÐART 6, RESTRICT COORDINATE RANGE

; RESTRICT X VALUE
        LDX #$00; 0 MEANS "X STUFF"
        JSR ÒESTRICT
; RESTRICT Y VALUE
        LDX #$02; 2 MEANS "Y STUFF"
        JSR ÒESTRICT


; --- ÐART 7, POSITIONING SPRITES

; ÓET SPRITES' X POSITIONS
        LDA ÐOINTERØNOW
        CLC
        ADC #ÓPRITEÏFFSET_Ø
        STA ÓPRITEÁ_Ø; SET BOTH SPRITES
        STA ÓPRITEÂ_Ø
        LDA ÓPRITES_ÏÆ; GET X OVERFLOW
        BCS ÓETÏÆ
        LDX ÐOINTERØNOW+1
        BNE ÓETÏÆ
        AND #ÓPRITES_ÂITMASK ÅÏÒ $FF
        BCC ÓTOREÏÆ; Ã IS CLEAR HERE

ÓETÏÆ   ORA #ÓPRITES_ÂITMASK
ÓTOREÏÆ STA ÓPRITES_ÏÆ; SET X OVERFLOW

; ÓET SPRITES' Y POSITIONS
        LDA ÐOINTERÙNOW
        CLC
        ADC #ÓPRITEÏFFSET_Ù
        STA ÓPRITEÁ_Ù
        STA ÓPRITEÂ_Ù
; ÔHE Y VALUE'S HIGH BYTE IS USELESS IN
; THIS CASE.


; --- ÐART 8, MAKING CHAR COORDINATES

; ÃONVERT X COORDINATE. ÔHERE ARE
; DIFFERENT "BEST" ROUTINES FOR
; DIFFERENT RESOLUTIONS, SO É'VE GIVEN
; THE ÖÉÃ AND ÖÄÃ ROUTINES.
        LDA ÐOINTERØNOW
        LSR
        LSR
        LSR
        LDX ÐOINTERØNOW+1
        BEQ ÓETÃØ; ÖÉÃ ONLY
        ORA #$20; ÖÉÃ ONLY
;       ORA ÏRÔABLE,X; ÖÄÃ ONLY
ÓETÃØ   STA ÃHARØ

; ÃONVERT Y COORDINATE.
        LDA ÐOINTERÙNOW
        LSR
        LSR
        LSR
        STA ÃHARÙ


; --- ÁDD FURTHER PARTS HERE

; ÈERE YOU CAN ADD FURTHER ROUTINES,
; FOR EXAMPLE TO USE THE BUTTON STATES
; TO FAKE KEYPRESSES ETC.


; --- ÔHE END

; ÔHE INITIALISATION ROUTINE SETS THE
; ARGUMENT TO THE ADDRESS OF THE
; PREVIOUS ÉÒÑ ROUTINE.
MOD16   JMP $FFFF; (SELF-MODIFYING)

; ÔHIS TABLE IS FOR PART 8.
;ÏRÔABLE !BYTE 0,32,64; ÖÄÃ ONLY


; --- "ÒESTRICT" SUBROUTINE

ÐOINTERØMAX !WORD ÍAXIMUMÃOORDINATEØ
ÐOINTERÙMAX !WORD ÍAXIMUMÃOORDINATEÙ
; "Y" WORD MUST FOLLOW DIRECTLY AFTER
; "X" WORD IN MEMORY.

ÒESTRICT
; ÒESTRICT INTERNAL COORDINATES TO
; CONFIGURED RANGE. ÅNTRY CONDITIONS:
; Ø IS DIRECTION HANDLE (0 = X, 2 = Y)
        LDA ÐOINTERØNOW+1,X
        BMI ÓETÔO0
        CMP ÐOINTERØMAX+1,X
        BCC ÅOSR
        BNE ÒESETÃO
        LDA ÐOINTERØMAX,X
        CMP ÐOINTERØNOW,X
        BCS ÅOSR
ÒESETÃO LDA ÐOINTERØMAX,X
        LDY ÐOINTERØMAX+1,X
        JMP ÄEFÃO

ÓETÔO0  LDA #0
        TAY
ÄEFÃO   STA ÐOINTERØNOW,X
        STY ÐOINTERØNOW+1,X
ÅOSR    RTS


; --- "ÐOT" SUBROUTINE

; ÔHIS ROUTINE COMPUTES THE MOUSE
; MOVEMENTS AND THEREFORE CONTAINS THE
; SELF-CALIBRATION STUFF AND THE OTHER
; IMPROVEMENTS OVER THE STANDARD 1351
; DRIVER.
ÐOTÍAX !WORD 0; MAX. ÐÏÔS YET PLUS 1 !
ÐOTÍIN !WORD $FFFF; LOWEST ÐÏÔS YET
ÐOTÏLD !WORD 0; OLD VALUES
ÐOT×IDTH !WORD 0; INTERVAL WIDTH
ÈALFÐOT×IDTH !WORD 0; HALF WIDTH
; (BUFFERED FOR SPEED INCREASE)
; ÔHE ABOVE VARIABLES ARE NOT REALLY
; WORDS: ÔHE FIRST BYTE IS THE X VALUE,
; THE SECOND BYTE IS THE Y VALUE
; RESPECTIVELY.

ÐOTÄELTA
; ÃOMPUTE THE SIGNED DISTANCE OF MOUSE
; MOVEMENT. ÅNTRY CONDITIONS:
; Ø IS DIRECTION HANDLE (0 = X, 1 = Y)
; ÅXIT CONDITIONS:
; Á/Ù ARE SIGNED DISTANCE (LOW/HIGH)

; ÆIRST, GET NEW VALUE AND CLEAR
; "RECALCULATE SIGNAL WIDTH" FLAG.
        LDA SID_POT,X
        LDY #$00
; ÃHECK WHETHER NEW VALUE IS LOWER THAN
; LOWEST KNOWN.
        CMP ÐOTÍIN,X
        BCS M0
; ÓTORE NEW "LOWEST" UND SET
; "RECALCULATE SIGNAL WIDTH" FLAG.
        STA ÐOTÍIN,X
        LDY #$FF

; ÃHECK WHETHER NEW VALUE IS HIGHER
; THAN HIGHEST KNOWN.
M0      CMP ÐOTÍAX,X
        BCC M1
; ÓET "RECALCULATE SIGNAL WIDTH" FLAG
; AND STORE NEW "HIGHEST".
        LDY #$FF
        PHA; ÒEMEMBER CURRENT VALUE
        ADC #$00; ÁDD ONE (Ã IS SET)
        STA ÐOTÍAX,X
; ÖALUE $FF (0 AFTER ADDING) MEANS THAT
; THERE IS NO MOUSE CONNECTED, SO RESET
; MIN/MAX IN THAT CASE.
        BEQ ÒESETÍÍ; ÓTACK IS UNTIDY...
        PLA; ÒESTORE CURRENT VALUE

; ÉF FLAG IS SET, RECALCULATE SIGNAL
; WIDTH.
M1
        INY; ÃHECK FLAG
        BNE M3
        TAY; ÂUFFER CURRENT VALUE.
        LDA ÐOTÍAX,X; ÇET HIGHEST+1
        SEC; ÓUBTRACT LOWEST
        SBC ÐOTÍIN,X
        BCC M2
        STA ÐOT×IDTH,X; ÓTORE SIGNAL
        LSR; WIDTH AND HALF SIGNAL
        STA ÈALFÐOT×IDTH,X; WIDTH
M2      TYA; ÒESTORE CURRENT VALUE.

; ÃALCULATE DISTANCE
M3      TAY; ÂUFFER CURRENT VALUE.
        SEC
        SBC ÐOTÏLD,X
        PHA
        TYA
        STA ÐOTÏLD,X
        PLA
        BEQ ZERO; ÉF NOT MOVED, EXIT.
        BCC MINUS; ÎEGATIVE DIFFERENCE

; ÐOSITIVE DIFFERENCE:
; ÃHECK WHETHER MOVEMENT CAUSED A VALUE
; WRAP-AROUND.
        CMP ÈALFÐOT×IDTH,X
        BCC ÄECREASE
        BEQ ÄECREASE
; ÉT DID, SO CALCULATE "REAL" DISTANCE
; AND JUMP TO EXIT
        ;SEC; Ã IS ALWAYS SET HERE
        SBC ÐOT×IDTH,X; ÆIX DISTANCE

; ×E NOW KNOW THAT THE (FIXED) DISTANCE
; IS REALLY NEGATIVE, SO WE FINALLY
; WIPE OUT THAT ANNOYING BIT 0 NOISE BY
; INCREMENTING THE VALUE.
ÉNCREASE
        ;CLC; Ã IS ALWAYS CLEAR HERE
        ADC #$01
        BEQ ZERO; ÉF INCREASING
; DELIVERS ZERO, JUMP TO ZERO HANDLER.
        LDY #$FF; ÓET UP HIGH BYTE FOR
; NEGATIVE VALUES.
        RTS

; ÎEGATIVE DIFFERENCE:
; ÃHECK WHETHER MOVEMENT CAUSED A VALUE
; WRAP-AROUND.
MINUS   EOR #$FF; ÃOMPLEMENT
; ÉF WE WOULD DO A REAL NEGATION (BY
; ADDING "1"), THEN WE WOULD NEED TO
; BRANCH USING ÂÃÃ *AND* ÂÅÑ. ÓO THE
; ABOVE WAY MIGHT BE HARDER TO
; UNDERSTAND, BUT IT IS BOTH SHORTER
; *AND* FASTER - WHICH É LIKE. :)
        CMP ÈALFÐOT×IDTH,X
        EOR #$FF; ÒESTORE VALUE
        BCC ÉNCREASE
; ÍOVEMENT CAUSED A VALUE WRAP-AROUND,
; SO CALCULATE "REAL" DISTANCE AND
; EXIT.
        CLC
        ADC ÐOT×IDTH,X; ÆIX DISTANCE

; ×E NOW KNOW THAT THE (FIXED) DISTANCE
; IS REALLY POSITIVE, SO WE FINALLY
; WIPE OUT THAT ANNOYING BIT 0 NOISE BY
; DECREMENTING THE VALUE.
ÄECREASE
        SEC
        SBC #$01

; ÎO DIFFERENCE OR POSITIVE DIFFERENCE;
; BOTH NEED ZERO AS THE HIGH BYTE.
ZERO    LDY #0
        RTS

; ÉF THERE IS NO MOUSE, RESET "LOWEST"
; ("HIGHEST" WILL HAVE BEEN RESET
; ALREADY) AND RETURN ZERO.
ÒESETÍÍ TAY; ÓET Ù TO ZERO.
        PLA; ÔIDY STACK
        LDA #$FF; ÒESET "LOWEST"
        STA ÐOTÍIN,X
        TYA; ÒETURN WITH Á/Ù = 0
        RTS


; --- ÉNCLUDE SPRITES

; ÂECAUSE THE Ã64 VERSION COPIES THE
; SPRITE DATA INTO THE TAPE BUFFER ON
; INITIALISATION, THE DATA IS INCLUDED
; RIGHT HERE.
; ÉN THE Ã128 VERSION, WE SKIP MEMORY
; UNTIL WE REACH $0E00 - THIS IS WHERE
; THE SPRITES ARE STORED BY DEFAULT.
;       !ALIGN $FFFF,$E00,$0;Ã128 ONLY
ÓPRITES !BINARY "POINTERSPRITES",, 2