WIP circle test (not working)

RANDOM_test.asm

@@ -0,0 +1,551 @@
+;    @com.wudsn.ide.lng.mainsourcefile=RANDOM_test.asm
+
+;mads RANDOM_test.asm -o:RANDOM_test.bin -d:TARGET=5200
+;mads RANDOM_test.asm -o:RANDOM_test.xex -d:TARGET=800
+
+
+;---------------------------------------------------
+.IFNDEF TARGET
+    .def TARGET = 800 ; 5200
+.ENDIF
+;---------------------------------------------------
+         OPT r+  ; saves 10 bytes, and probably works :) https://github.com/tebe6502/Mad-Assembler/issues/10
+
+;---------------------------------------------------
+
+;---------------------------------------------------
+;---------------------------------------------------
+FirstZpageVariable = $50
+    .zpvar DliColorBack     .byte = FirstZpageVariable
+    .zpvar ClearSky         .byte  ; $ff - Crear sky during drawmountains, 0 - no clear sky
+    .zpvar PaddleState      .byte  ; old state 2nd button for 2 buttons joysticks
+    .zpvar GradientNr       .byte
+    .zpvar GradientColors   .word
+    .zpvar JoystickNumber   .byte
+    .zpvar LazyFlag         .byte  ; 7 bit - run Lazy Darwin, 6 bit - run Lazy Boy or Darwin (!) after inventory
+                                   ; 0 - nothing
+    .zpvar SpyHardFlag      .byte  ; >$7f - run SpyHard after inventory
+    .zpvar Vdebug           .byte  ; "visual debug" flag ($00 - off, $ff - on)
+    .zpvar xdraw            .word  ; = $64 ;variable X for plot
+    .zpvar ydraw            .word  ; variable Y for plot 
+                                   ; (like in Atari Basic - Y=0 in upper right corner of the screen)
+    .zpvar xbyte            .word
+    .zpvar ybyte            .word
+    .zpvar CharCode         .byte
+    .zpvar fontind          .word
+    .zpvar tanknr           .byte
+    .zpvar oldplot          .word
+    .zpvar xc               .word
+    .zpvar temp             .word  ; temporary word for the most embeded loops only
+    .zpvar temp2            .word  ; same as above
+    .zpvar modify           .word  ; origially used to replace self-modyfying code
+    .zpvar tempXROLLER      .word  ; same as above for XROLLER routine (used also in result display routine)
+    .zpvar xtempDRAW        .word  ; same as above for XDRAW routine
+    .zpvar ytempDRAW        .word  ; same as above for XDRAW routine
+    .zpvar tempor2          .word
+    .zpvar CreditsVScrol    .byte
+    ;--------------temps used in circle routine
+    .zpvar xi               .word  ; X (word) in draw routine
+    .zpvar fx               .byte
+    .zpvar yi               .word  ; Y (word) in draw routine
+    .zpvar fy               .byte
+    .zpvar xk               .word
+    .zpvar fs               .byte
+    .zpvar yc               .byte  ; ycircle - temporary for circle
+    .zpvar dx               .word
+    .zpvar dy               .word
+    .zpvar dd               .word
+    .zpvar di               .word
+    .zpvar dp               .word
+    ;----------------------------
+    .zpvar UnderTank1       .byte
+    .zpvar UnderTank2       .byte
+    ;----------------------------
+    .zpvar TestFlightFlag   .byte  ; For AI test flights ($ff - test, $00 - standard shoot flight)
+    .zpvar weaponPointer    .word
+    .zpvar dliCounter       .byte
+    .zpvar pressTimer       .byte
+    .zpvar NTSCcounter      .byte
+    .zpvar sfx_effect       .byte
+    .zpvar RMT_blocked      .byte
+    .zpvar ScrollFlag       .byte
+    .zpvar SkStatSimulator  .byte
+    .zpvar FloatingAlt      .byte  ; floating tank altitude
+    .zpvar OverTankDir      .byte  ; (0 go right, $ff go left) direction of bypassing tanks on screen
+
+    ; --------------OPTIMIZATION VARIABLES--------------
+    .zpvar Force            .word
+    .zpvar Force_           .byte  ; Force is 3 bytes long
+    .zpvar Angle            .byte
+    .zpvar Parachute        .byte  ; are you insured with parachute?
+    .zpvar color            .byte
+    .zpvar Erase            .byte  ; if 1 only mask of the character is printed
+                                   ; on the graphics screen. if 0 character is printed normally
+    .zpvar radius           .byte
+    .zpvar decimal          .word
+    .zpvar NumberOfPlayers  .byte  ; current number of players (counted from 1)
+    .zpvar Counter          .byte  ; temporary Counter for outside loops
+    .zpvar ExplosionRadius  .byte
+    .zpvar FunkyBombCounter .byte
+    .zpvar ResultY          .byte
+    .zpvar xcircle          .word
+    .zpvar ycircle          .word
+    .zpvar vy               .word
+    .zpvar vy_              .word  ; 4 bytes
+    .zpvar vx               .word
+    .zpvar vx_              .word  ; 4 bytes
+    .zpvar HitFlag          .byte  ; $ff when missile hit ground, $00 when no hit,
+                                   ; $01-$06 tank index+1 when hit tank
+    .zpvar PositionOnTheList   .byte ; pointer position on the list being displayed
+    .zpvar FirstKeypressDelay  .byte
+    .zpvar IsEndOfTheFallFlag  .byte ;for small speedup ground falling
+    .zpvar TankSequencePointer .byte
+    .zpvar WindChangeInRound   .byte ; wind change after each turn (not round only) flag
+                                     ; (0 - round only, >0 - each turn)
+    .zpvar RandomMountains  .byte  ; mountains type change after each turn flag
+                                   ; (0 - round only, >0 - each turn)
+    .zpvar FastSoilDown     .byte  ; 0 - standard, >0 - fast
+    .zpvar BlackHole        .byte  ; 0 - no, >0 - yes
+    .zpvar XHit             .word
+    .zpvar delta            .word
+    .zpvar HowMuchToFall    .byte
+    .zpvar magic            .word  ; worst var name in the whole business
+    .zpvar xtraj            .word
+    .zpvar xtraj_           .byte  ; 3 bytes
+    .zpvar ytraj            .word
+    .zpvar ytraj_           .byte  ; 3 bytes
+    .zpvar Wind             .word
+    .zpvar Wind_            .word  ; 4 bytes
+    .zpvar RangeLeft        .word
+    .zpvar RangeRight       .word
+    .zpvar NewAngle         .byte
+    .zpvar escFlag          .byte  ; 7 bit - Exit game, 
+                                   ; 6 bit - Exit to GameOver (cleared - exit to Menu), 0 - nothing
+    .zpvar LineYdraw        .byte
+    .zpvar LineXdraw        .word
+    .zpvar plot4x4color     .byte  ; $00 / $ff
+    .zpvar Multiplier       .word
+    .zpvar Multiplier_      .byte  ; 3 bytes
+    .zpvar HowToDraw        .byte
+    .zpvar DrawDirFactor    .byte
+    .zpvar gravity          .byte
+    .zpvar LineLength       .word
+    .zpvar tracerflag       .byte
+    .zpvar isInventory      .byte
+    .zpvar DifficultyLevel  .byte
+    .zpvar goleft           .byte
+    .zpvar OffsetDL1        .byte
+    .zpvar L1               .byte
+    HotNapalmFlag = FunkyBombCounter  ; variable reuse!
+    displayposition = modify
+    LineAddress4x4 = xcircle
+    ;* RMT ZeroPage addresses in artwork/sfx/scorch_str9-NTSC.rmt
+
+DISPLAY = $1000
+SCREENHEIGHT = 256
+screenwidth = 32
+;-----------------------------------------------
+; libraries
+;-----------------------------------------------
+    .IF TARGET = 800
+      icl 'Atari/lib/ATARISYS.ASM'
+      icl 'Atari/lib/MACRO.ASM'
+    .ELIF TARGET = 5200
+      OPT h-f+  ; no headers, single block --> cart bin file
+      icl 'Atari/lib/5200SYS.ASM'
+      icl 'Atari/lib/5200MACRO.ASM'
+      .enum @kbcode
+        _space = $00
+        _Y     = $01
+        _up    = $02
+        _O     = $03
+        _left  = $04
+        _tab   = $05
+        _right = $06
+        _A     = $07
+        _down  = $08
+        _I     = $09
+        _esc   = $0a
+        _help  = $0b  ; Visual Debug in 5200
+        _del   = $fc  ; $0c ;not used in 5200
+        _M     = $0d
+        _S     = $0e
+        _atari = $fd  ; not used in 5200
+        _ret   = $0c  ; fire in 5200
+        _none  = $0f
+      .ende
+    .ENDIF
+
+;-----------------------------------------------
+; variable declarations in RAM (no code)
+;-----------------------------------------------
+    ORG $3000
+    ; These tebles are at the beginning of memory pages becouse ....
+bittable1_long
+    .ds $100
+bittable2_long
+    .ds $100
+linetableL
+    .ds (screenHeight)
+linetableH
+    .ds (screenHeight)
+    
+
+    ; loading address
+    ORG $4000
+
+;--------------------------------------------------
+; Game Code
+;--------------------------------------------------
+FirstSTART
+    .IF TARGET = 5200
+      ; start in 5200 diagnostic mode
+      ; move original startup procedure to RAM
+
+    Modified5200Splash = $2100  ; apparently there is some free space here
+      ; check kernel version
+    Atari5200KernelByte = $fff8
+      ; $32 - 4 joy
+      ; $00 - 2 joy
+      ; $ff - Altirra kernel
+
+    lda Atari5200KernelByte
+    beq rom2joy
+    cmp #$32
+    beq rom4joy
+altirra_kernel
+    mwa #Modified5200Splash+$8a modify
+    bne @+  ; JMP
+
+rom4joy
+    mwa #Modified5200Splash+$16b modify
+    bne @+  ; JMP
+
+rom2joy
+    mwa #Modified5200Splash+$181 modify
+@
+    mwa $fffc temp  ; startup proc address
+    mwa #Modified5200Splash temp2
+    jsr CopyFromROM
+    ; modify the end of the splash procedure
+    lda #$60  ; rts
+    sta (temp2),y
+
+    jsr Modified5200Splash+$0f  ; after the diag cart detection
+    ; modify the text
+    splash_text = $3c80 ; '.scorch.supersystem.copyright.19xx.atari'
+    splash_year = splash_text + $1e
+    splash_copyright = splash_text + $14
+    ldy #19    ; 20 characters
+@     lda NewSplashText,y
+      sta splash_copyright,y
+      dey
+    bpl @-
+
+    ; splash screen delay. maybe add fire to speed up?
+@    cpx RTCLOK+1
+    bne @-
+no5200splash
+    .ENDIF
+StartAfterSplash
+
+    ; generate linetables
+    jsr GenerateLineTable
+
+    .IF TARGET = 800
+      ; pokeys init
+      lda #3        ; stereo (pseudo)
+      sta POKEY+$0f ; stereo
+      sta POKEY+$1f ; stereo
+    .ELIF TARGET = 5200
+      mva #$7f SkStatSimulator
+    .ENDIF
+
+
+    .IF TARGET = 5200
+      mva #$0f STICK0
+      mva #$04 CONSOL5200      ; Speaker off, Pots enabled, port #1 selected
+      mwa #kb_continue VKEYCNT ; Keyboard handler
+    .ENDIF
+    VMAIN VBLinterrupt,7       ; jsr SetVBL
+
+    mva #2 chactl              ; necessary for 5200
+
+        mwa #dl dlptrs  ; issue #72 (glitches when switches)
+    mva #@dmactl(narrow|dma) dmactls
+    
+@    
+    mva random xdraw
+
+    ;mva random ydraw
+    lda random
+    ;and #%00111111
+    sta ydraw
+    
+    ; let's calculate coordinates from xdraw and ydraw
+
+    ;xbyte = xbyte/8
+    lda xdraw
+    :3 lsr
+    sta xbyte
+    ;---
+    ldx ydraw
+    ldy linetableL,x
+    lda linetableH,x
+    sta xbyte+1
+
+    ldx xdraw   ; optimization (256 bytes long bittable)
+    
+    lda (xbyte),y
+    ora bittable1_long,x
+    sta (xbyte),y
+
+    
+    jmp @-
+    
+dl
+    .byte SKIP8, SKIP8, SKIP8
+    .byte LMS|MODEF
+    .word DISPLAY
+    :127 .byte MODEF
+    .byte JVB
+    .word dl
+    
+;--------------------------------------------------
+.proc GenerateLineTable
+
+    mwa #display temp
+    mwa #linetableL temp2
+    mwa #linetableH modify
+    ldy #0
+@     lda temp
+      sta (temp2),y
+      lda temp+1
+      sta (modify),y
+      adw temp #screenwidth
+      iny
+      cpy #0  ;#screenheight+1
+    bne @-
+    ; and bittables for fastest plot and point (thanks @jhusak)
+    ldy #0
+    lda #$40
+@   asl
+    adc #0
+    sta bittable1_long,y
+    tax
+    eor #%11111111
+    sta bittable2_long,y
+    txa
+    dey
+    bne @-
+endof
+    rts
+.endp
+; -----------------------------------------
+.proc plot  ;plot (xdraw, ydraw, color)
+; color == 1 --> put pixel
+; color == 0 --> erase pixel
+; xdraw (word) - X coordinate
+; ydraw (word) - Y coordinate
+; this is one of the most important routines in the whole
+; game. If you are going to speed up the game, start with
+; plot - it is used by every single effect starting from explosions
+; through line drawing and small text output!!!
+;
+; Optimized by 0xF (Fox) THXXXX!!!
+
+; -----------------------------------------
+MakePlot
+    ; let's calculate coordinates from xdraw and ydraw
+
+    ;xbyte = xbyte/8
+    lda xdraw
+    :3 lsr
+    sta xbyte
+    ;---
+    ldx ydraw
+    ldy linetableL,x
+    lda linetableH,x
+    sta xbyte+1
+
+    ldx xdraw   ; optimization (256 bytes long bittable)
+    
+    lda (xbyte),y
+    ora bittable1_long,x
+    sta (xbyte),y
+    rts
+.endp
+;--------------------------------------------------
+MakeDarkScreen
+;--------------------------------------------------
+    mva #0 dmactls             ; dark screen
+    ; and wait one frame :)
+;--------------------------------------------------
+.proc WaitOneFrame
+;--------------------------------------------------
+    jsr CheckStartKey             ; START KEY
+    seq:wait                   ; or waitRTC ?
+    rts
+.endp
+
+;--------------------------------------------------
+.proc PauseYFrames
+; Y - number of frames to wait (divided by 2)
+; pauses for maximally 510 frames (255 * 2)
+;--------------------------------------------------
+@   jsr WaitOneFrame
+    jsr WaitOneFrame
+    dey
+    bne @-
+    rts
+.endp
+
+;-------------------------------------------------
+.proc CopyFromROM
+;-------------------------------------------------
+;copy from CART to RAM
+; trashes: Y
+; temp: source
+; temp2: destination
+; modify: destination-end
+;usage:
+;    mwa #DisplayCopyRom temp
+;    mwa #display temp2
+;    mwa #DisplayCopyEnd+1 modify
+;    jsr CopyFromROM
+
+    ldy #0
+@     lda (temp),y
+      sta (temp2),y
+      inw temp
+      inw temp2
+      cpw temp2 modify
+    bne @-
+    rts
+.endp
+
+;--------------------------------------------------
+.proc VBLinterrupt
+    mva #0 dliCounter
+    mva #$02 DliColorBack
+
+    lda PAL
+    and #%00001110
+    beq itsPAL
+    ;it is NTSC here
+    dec NTSCcounter
+    bne itsPAL
+    mva #6 NTSCcounter
+    bne SkippedIfNTSC ; skip doing VBL things each 6 frames in Amerika, Amerika
+                ; We're all living in Amerika, Coca Cola, Wonderbra
+
+itsPAL
+    ; pressTimer is trigger tick counter. always 50 ticks / s
+    bit:smi:inc pressTimer ; timer halted if >127. max time measured 2.5 s
+
+SkippedIfNTSC
+
+    .IF TARGET = 800
+        ; support for joysticks :)
+        ldx JoystickNumber
+        lda STICK0,x
+        sta STICK0
+        lda STRIG0,x
+        sta STRIG0
+        ; and PADDLES (2 and 3 joystick button)
+        txa
+        asl
+        tax
+        lda PADDL0,x
+        sta PADDL0
+        jmp XITVBV
+    .ELIF TARGET = 5200
+        lda SkStatSimulator
+        smi:inc SkStatSimulator
+        
+        lda JoystickNumber        ; select port
+        ora #%00000100          ; Speaker off, Pots enabled
+        sta CONSOL5200
+
+        center = 114            ;Read analog stick and make it look like a digital stick
+        threshold = 60
+
+        lda JoystickNumber
+        asl
+        tax
+        lda paddl0,x            ;Read POT0 value (horizontal position)
+        cmp #center+threshold       ;Compare with right threshold
+        rol stick0          ;Feed carry into digital stick value
+        cmp #center-threshold       ;Compare with left threshold
+        rol stick0          ;Feed carry into digital stick value
+
+        lda paddl1,x            ;Read POT1 value (vertical position)
+        cmp #center+threshold       ;Compare with down threshold
+        rol stick0          ;Feed carry into digital stick value
+        cmp #center-threshold       ;Compare with down threshold
+        rol stick0          ;Feed carry into digital stick value
+
+        lda stick0          ;0 indicates a press so the right/down values need to be inverted
+        eor #2+8
+        and #$0f
+        sta stick0
+
+        ldx JoystickNumber
+        ; check shift key (5200 second fire button)
+        lda SKSTAT
+        :3 lsr        ; third bit
+        and trig0,x    ; and first button
+        ;lda trig0,x
+        sta strig0        ;Move hardware to shadow
+
+        mva chbas chbase
+
+        lda skstat          ;Reset consol key shadow is no key is pressed anymore
+        and #4
+        beq @+
+          mva #consol_reset consol
+          mva #@kbcode._none kbcode
+@
+exit
+        pla
+        tay
+        pla
+        tax
+        pla
+        rti
+    .ENDIF
+.endp
+    .IF TARGET = 5200
+.proc kb_continue
+    cmp #$0c    ; START key on 5200 keypad
+    beq StartPressed
+    sta kbcode          ;Store key code in shadow.
+    mva #0 SkStatSimulator
+    beq VBLinterrupt.exit
+StartPressed
+    mvx #%00000110 CONSOL   ; virtual CONSOL Start key pressed
+    bne VBLinterrupt.exit
+.endp
+    .ENDIF
+
+;--------------------------------------------------
+.proc CheckStartKey
+;--------------------------------------------------
+    lda CONSOL  ; turbo mode
+    and #%00000001 ; START KEY
+    rts
+.endp
+;-------------------------------------------------
+  .ECHO "Bytes on top left: ",$bfe8-* ; ROM_SETTINGS-*
+  .IF TARGET = 800
+     run FirstSTART
+  .ELIF TARGET = 5200
+    .IF * > ROM_SETTINGS-1
+      .ERROR 'Code too long to fit in 5200'
+    .ENDIF
+    org ROM_SETTINGS             ; 5200 ROM settings address $bfe8
+    ;     "01234567890123456789"
+    .byte " pokey random test  " ; 20 characters title
+    .byte " ", $ff               ; $BFFD == $ff means diagnostic cart, no splash screen
+    .word FirstSTART
+  .ENDIF

circle_test.asm

@@ -0,0 +1,352 @@
+      icl 'Atari/lib/ATARISYS.ASM'
+      icl 'Atari/lib/MACRO.ASM'
+      
+screenheight = 200
+screenbytes = 40
+screenwidth  = screenBytes*8  ; Max screenwidth = 512!!!
+      FirstZpageVariable = $50
+    .zpvar DliColorBack     .byte = FirstZpageVariable
+    .zpvar ClearSky         .byte  ; $ff - Crear sky during drawmountains, 0 - no clear sky
+    .zpvar PaddleState      .byte  ; old state 2nd button for 2 buttons joysticks
+    .zpvar GradientNr       .byte
+    .zpvar GradientColors   .word
+    .zpvar JoystickNumber   .byte
+    .zpvar LazyFlag         .byte  ; 7 bit - run Lazy Darwin, 6 bit - run Lazy Boy or Darwin (!) after inventory
+                                   ; 0 - nothing
+    .zpvar SpyHardFlag      .byte  ; >$7f - run SpyHard after inventory
+    .zpvar Vdebug           .byte  ; "visual debug" flag ($00 - off, $ff - on)
+    .zpvar xdraw            .word  ; = $64 ;variable X for plot
+    .zpvar ydraw            .word  ; variable Y for plot 
+                                   ; (like in Atari Basic - Y=0 in upper right corner of the screen)
+    .zpvar xbyte            .word
+    .zpvar ybyte            .word
+    .zpvar CharCode         .byte
+    .zpvar fontind          .word
+    .zpvar tanknr           .byte
+    .zpvar oldplot          .word
+    .zpvar xc               .word
+    .zpvar temp             .word  ; temporary word for the most embeded loops only
+    .zpvar temp2            .word  ; same as above
+    .zpvar modify           .word  ; origially used to replace self-modyfying code
+    .zpvar tempXROLLER      .word  ; same as above for XROLLER routine (used also in result display routine)
+    .zpvar xtempDRAW        .word  ; same as above for XDRAW routine
+    .zpvar ytempDRAW        .word  ; same as above for XDRAW routine
+    .zpvar tempor2          .word
+    .zpvar CreditsVScrol    .byte
+    ;--------------temps used in circle routine
+    .zpvar xi               .word  ; X (word) in draw routine
+    .zpvar fx               .byte
+    .zpvar yi               .word  ; Y (word) in draw routine
+    .zpvar fy               .byte
+    .zpvar xk               .word
+    .zpvar fs               .byte
+    .zpvar yc               .byte  ; ycircle - temporary for circle
+    .zpvar dx               .word
+    .zpvar dy               .word
+    .zpvar dd               .word
+    .zpvar di               .word
+    .zpvar dp               .word
+    ;----------------------------
+    .zpvar UnderTank1       .byte
+    .zpvar UnderTank2       .byte
+    ;----------------------------
+    .zpvar TestFlightFlag   .byte  ; For AI test flights ($ff - test, $00 - standard shoot flight)
+    .zpvar weaponPointer    .word
+    .zpvar dliCounter       .byte
+    .zpvar pressTimer       .byte
+    .zpvar NTSCcounter      .byte
+    .zpvar sfx_effect       .byte
+    .zpvar RMT_blocked      .byte
+    .zpvar ScrollFlag       .byte
+    .zpvar SkStatSimulator  .byte
+    .zpvar FloatingAlt      .byte  ; floating tank altitude
+    .zpvar OverTankDir      .byte  ; (0 go right, $ff go left) direction of bypassing tanks on screen
+
+    ; --------------OPTIMIZATION VARIABLES--------------
+    .zpvar Force            .word
+    .zpvar Force_           .byte  ; Force is 3 bytes long
+    .zpvar Angle            .byte
+    .zpvar Parachute        .byte  ; are you insured with parachute?
+    .zpvar color            .byte
+    .zpvar Erase            .byte  ; if 1 only mask of the character is printed
+                                   ; on the graphics screen. if 0 character is printed normally
+    .zpvar radius           .byte
+    .zpvar decimal          .word
+    .zpvar NumberOfPlayers  .byte  ; current number of players (counted from 1)
+    .zpvar Counter          .byte  ; temporary Counter for outside loops
+    .zpvar ExplosionRadius  .byte
+    .zpvar FunkyBombCounter .byte
+    .zpvar ResultY          .byte
+    .zpvar xcircle          .word
+    .zpvar ycircle          .word
+    .zpvar vy               .word
+    .zpvar vy_              .word  ; 4 bytes
+    .zpvar vx               .word
+    .zpvar vx_              .word  ; 4 bytes
+    .zpvar HitFlag          .byte  ; $ff when missile hit ground, $00 when no hit,
+                                   ; $01-$06 tank index+1 when hit tank
+    .zpvar PositionOnTheList   .byte ; pointer position on the list being displayed
+    .zpvar FirstKeypressDelay  .byte
+    .zpvar IsEndOfTheFallFlag  .byte ;for small speedup ground falling
+    .zpvar TankSequencePointer .byte
+    .zpvar WindChangeInRound   .byte ; wind change after each turn (not round only) flag
+                                     ; (0 - round only, >0 - each turn)
+    .zpvar RandomMountains  .byte  ; mountains type change after each turn flag
+                                   ; (0 - round only, >0 - each turn)
+    .zpvar FastSoilDown     .byte  ; 0 - standard, >0 - fast
+    .zpvar BlackHole        .byte  ; 0 - no, >0 - yes
+    .zpvar XHit             .word
+    .zpvar delta            .word
+    .zpvar HowMuchToFall    .byte
+    .zpvar magic            .word  ; worst var name in the whole business
+    .zpvar xtraj            .word
+    .zpvar xtraj_           .byte  ; 3 bytes
+    .zpvar ytraj            .word
+    .zpvar ytraj_           .byte  ; 3 bytes
+    .zpvar Wind             .word
+    .zpvar Wind_            .word  ; 4 bytes
+    .zpvar RangeLeft        .word
+    .zpvar RangeRight       .word
+    .zpvar NewAngle         .byte
+    .zpvar escFlag          .byte  ; 7 bit - Exit game, 
+                                   ; 6 bit - Exit to GameOver (cleared - exit to Menu), 0 - nothing
+    .zpvar LineYdraw        .byte
+    .zpvar LineXdraw        .word
+    .zpvar plot4x4color     .byte  ; $00 / $ff
+    .zpvar Multiplier       .word
+    .zpvar Multiplier_      .byte  ; 3 bytes
+    .zpvar HowToDraw        .byte
+    .zpvar DrawDirFactor    .byte
+    .zpvar gravity          .byte
+    .zpvar LineLength       .word
+    .zpvar tracerflag       .byte
+    .zpvar isInventory      .byte
+    .zpvar DifficultyLevel  .byte
+    .zpvar goleft           .byte
+    .zpvar OffsetDL1        .byte
+    .zpvar L1               .byte
+      
+;-----------------------------------------------
+; variable declarations in RAM (no code)
+;-----------------------------------------------
+    ORG $2000
+    ; These tebles are at the beginning of memory pages becouse ....
+bittable1_long
+    .ds $100
+bittable2_long
+    .ds $100
+linetableL
+    .ds (screenHeight)
+linetableH
+    .ds (screenHeight)
+oldora  .DS [5]
+OldOraTemp .DS 1
+oldplotH .DS [5]
+oldplotL .DS [5]
+oldply  .DS [5]
+WhichUnPlot .DS 1
+
+;--------------------------------------------------
+.proc GenerateLineTable
+
+    mwa #display temp
+    mwa #linetableL temp2
+    mwa #linetableH modify
+    ldy #0
+@     lda temp
+      sta (temp2),y
+      lda temp+1
+      sta (modify),y
+      adw temp #screenwidth
+      iny
+      cpy #0  ;#screenheight+1
+    bne @-
+    ; and bittables for fastest plot and point (thanks @jhusak)
+    ldy #0
+    lda #$40
+@   asl
+    adc #0
+    sta bittable1_long,y
+    tax
+    eor #%11111111
+    sta bittable2_long,y
+    txa
+    dey
+    bne @-
+endof
+    rts
+.endp
+
+    
+; -----------------------------------------
+.proc unPlot
+; plots a point and saves the plotted byte, reverts the previous plot.
+; -----------------------------------------
+    ldx #0 ; only one pixel
+unPlotAfterX
+    stx WhichUnPlot
+
+    ; first remake the oldie
+    lda oldplotL,x
+    sta oldplot
+    lda oldplotH,x
+    sta oldplot+1
+
+    ldy oldply,x
+    lda oldora,x
+    sta (oldplot),y
+
+
+    ; is it not out of the screen ????
+    cpw ydraw #screenheight
+    jcc CheckX
+    mwa #0 ydraw
+CheckX
+    cpw xdraw #screenwidth
+    jcs EndOfUnPlot
+MakeUnPlot
+    ; let's count coordinates taken from xdraw and ydraw
+    ;xbyte = xbyte/8
+    lda xdraw+1
+    lsr
+    lda xdraw
+    ror ;just one bit over 256. Max screenwidth = 512!!!
+    lsr
+    lsr
+;---
+    tay
+    ldx WhichUnPlot
+    ;tya
+    sta oldply,x
+
+    ldx ydraw
+    lda linetableL,x
+    sta xbyte
+    sta oldplot
+    lda linetableH,x
+    sta xbyte+1
+    sta oldplot+1
+
+;    lda xdraw
+;    and #$7
+;    tax
+    ldx xdraw   ; optimization (256 bytes long bittable)
+    
+    lda color
+    bne ClearUnPlot
+
+    ;plotting here
+    lda (xbyte),y
+    sta OldOraTemp
+    ora bittable1_long,x
+    sta (xbyte),y
+    bne ContinueUnPlot ; allways <>0
+ClearUnPlot
+    lda (xbyte),y
+    sta OldOraTemp
+    and bittable2_long,x
+    sta (xbyte),y
+ContinueUnPlot
+    ldx WhichUnPlot
+    lda OldOraTemp
+    sta oldora,x
+    lda oldplot
+    sta oldplotL,x
+    lda oldplot+1
+    sta oldplotH,x
+    ; and now we must solve the problem of several plots
+    ; in one byte
+    ldx #4
+    ldy WhichUnPlot
+LetsCheckOverlapping
+    cpx WhichUnPlot
+    beq SkipThisPlot
+    lda oldplotL,x
+    cmp oldplotL,y
+    bne NotTheSamePlot
+    lda oldplotH,x
+    cmp oldplotH,y
+    bne NotTheSamePlot
+    lda oldply,x
+    cmp oldply,y
+    bne NotTheSamePlot
+    ; the pixel is in the same byte so let's take correct contents
+    lda oldora,x
+    sta oldora,y
+NotTheSamePlot
+SkipThisPlot
+    dex
+    bpl LetsCheckOverlapping
+EndOfUnPlot
+    rts
+.endp
+
+; -----------------------------------------
+.proc plot  ;plot (xdraw, ydraw, color)
+; color == 1 --> put pixel
+; color == 0 --> erase pixel
+; xdraw (word) - X coordinate
+; ydraw (word) - Y coordinate
+; this is one of the most important routines in the whole
+; game. If you are going to speed up the game, start with
+; plot - it is used by every single effect starting from explosions
+; through line drawing and small text output!!!
+;
+; Optimized by 0xF (Fox) THXXXX!!!
+
+; -----------------------------------------
+    ; is it not over the screen ???
+    cpw ydraw #(screenheight+1); changed for one additional line. cpw ydraw #(screenheight-1)
+    bcs unPlot.EndOfUnPlot ;nearest RTS
+CheckX02
+    cpw xdraw #screenwidth
+    bcs EndOfPlot
+MakePlot
+    ; let's calculate coordinates from xdraw and ydraw
+
+    ;xbyte = xbyte/8
+    lda xdraw+1
+    lsr
+    lda xdraw
+    ror ;just one bit over 256. Max screenwidth = 512!!!
+    lsr
+    lsr
+    sta xbyte
+    ;---
+    ldx ydraw
+    ldy linetableL,x
+    lda linetableH,x
+    sta xbyte+1
+
+;    lda xdraw
+;    and #$7
+;    tax
+    ldx xdraw   ; optimization (256 bytes long bittable)
+    
+    lda color
+    bne ClearPlot
+
+    lda (xbyte),y
+    ora bittable1_long,x
+    sta (xbyte),y
+EndOfPlot
+    rts
+ClearPlot
+    lda (xbyte),y
+    and bittable2_long,x
+    sta (xbyte),y
+    rts
+.endp
+      
+      icl 'circle1.asm'
+      ;icl 'circle2.asm'
+      
+start
+    ;jsr generatelinetable
+    halt
+    
+
+    run start
+    .align $1000
+    .ds 10
+display