; *** A S T E R O I D S *** ; Copyright 1979 Atari ; Designer: Brad Stewart ; Analyzed, labeled and commented ; by Thomas Jentzsch (JTZ) ; Last Update: 05.08.2003 (v0.5) ; PAL conversion notes: ; The conversion is only minimal, but (unlike Activision) Atari at least ; adjusted the screenheight. Except for the asteroids trajectories the game ; speed is completely unadjusted. When converting the copyrighted version to ; PAL again they "forgot" to adjust a few parameters. The colors for the ; flickering objects in NTSC are much brighter than for PAL ; Misc: ; - After disassmbling great games and codes like Pitfall! this code doesn't ; look too good. It wastes a lot of ROM (e.g. the two HMOVE tables, the over- ; complex collision detection and, last not least, the extremely ineffective ; repositioning routines right at the start of the code) and the RAM is ; sometimes also used not very effective. E.g. the asteroids list: it has ; space for 8 asteroids (one wrapped at the horizontal screen borders) but it ; wastes one whole slot (all three lists!) just to store a marker for the end ; of the list. That is 6 bytes wasted for just two (unnecessary) markers! ; With a little bit more clever coding the code (without copyright) might ; have fitted into 4K. ; - The number of asteroids depends on the score: ; <1,000 points -> 4, <15,000 points -> 6, >=15,000 point -> 8 ; - As stated above, the game only supports 2x7 asteroids. So if you destroy ; all four large asteroids moving in one y-direction, the last one only ; creates one single medium sized one. ; - The collision routines are not only complex but also not very reliable. ; The collisions aren't checked every frame (up to every 12th!). ; - There are two kernels, which are displayed alternating (asteroids, other ; objects). Therefore everything - except for the score display - flickers at ; 30/25Hz. ; - Originally it was planned to display the remaining ships instead of a ; simple number! The whole source code is still there and can be easily ; reenabled again. Because the color of the displayed ships was not converted ; I am sure disabling this code was done before converting the game to PAL. ; - Though the manual says that UFOs start at 7,500 points they actually start ; at 7,000 points. ; - The version without the copyright notice is no hack. The notice was added ; later, causing a lot of code to be moved at a slightly different address. ; - Maybe the children modes where added later or game #33 was originally ; planned to be game #65. ; - The number of random x-positions after hyperspace is limited to only a few ; values processor 6502 include vcs.h ;=============================================================================== ; A S S E M B L E R - S W I T C H E S ;=============================================================================== ORIGINAL = 0 ; original or DC version NTSC = 0 ; compiling for NTSC or PAL mode COPYRIGHT = 1 ; compiling version with copyright screen GARBAGE = 1 ; unused code in copyrighted version has garbage ; (slightly different in PAL version) SADISTROIDS = 0 ; enable for ultra fast asteroids ;=============================================================================== ; 2600 - C O N S T A N T S ;=============================================================================== ; value REFPx: REFLECT = %1000 ; values for NUSIZx: ONE_COPY = %000 TWO_COPIES = %001 TWO_COPIES_WIDE = %010 THREE_COPIES = %011 DOUBLE_SIZE = %101 THREE_COPIES_MED = %110 QUAD_SIZE = %111 MS_SIZE1 = %000000 MS_SIZE2 = %010000 MS_SIZE4 = %100000 MS_SIZE8 = %110000 ; values for bankswitching: BANK0 = $fff8 BANK1 = $fff9 ; color values: BLACK = $00 WHITE = $0e IF NTSC YELLOW = $10 BROWN = $20 RED = $40 MAGENTA = $50 BLUE1 = $70 BLUE2 = $90 CYAN = $a0 GREEN2 = $d0 OCHRE_GREEN = $e0 ELSE BROWN = $40 RED = $60 MAGENTA = $80 MAGENTA2 = $a0 BLUE1 = $b0 BLUE2 = $d0 CYAN = $90 GREEN2 = $30+2 OCHRE_GREEN = $20 ENDIF ;=============================================================================== ; G A M E - C O N S T A N T S ;=============================================================================== IF SADISTROIDS = 0 IF NTSC SPEED_SLOW = $70 ; horizontal delay of slow asteroids (1/7) SPEED_MEDIUM = $03 ; horizontal delay of medium asteroids (1/3) ; fast ones move always ELSE SPEED_SLOW = $50 ; 1/5 SPEED_MEDIUM = $02 ; 1/2 ENDIF ELSE SPEED_SLOW = $30 ; 1/3 SPEED_MEDIUM = $02 ; 1/2 ENDIF IF NTSC H_KERNEL = 89 ELSE H_KERNEL = 107 ENDIF PLAYER1_COL = RED+4 PLAYER2_COL = GREEN2+6 IF NTSC ; for NTSC they choose brighter colors for the ; flickering objects, which makes sense SHIP1_COL = PLAYER1_COL+8 SHIP2_COL = PLAYER2_COL+6 SATTELITE_COL = BLUE2+$c UFO_COL = OCHRE_GREEN+$c ELSE ; but why didn't they for PAL too? SHIP1_COL = PLAYER1_COL SHIP2_COL = PLAYER2_COL SATTELITE_COL = BLUE2+$2 UFO_COL = SHIP2_COL ; !!! ENDIF ID_SHIP = 4 ID_UFO = 5 ID_SATTELITE = 6 ID_SHOT1 = 7 ID_SHOT2 = 8 ID_SHOT_UFO = 9 ;flagLst constants: MEDIUM_SIZE = $20 SMALL_SIZE = $30 HIT_FLAG = $40 FAST_SPEED = $80 ; fast speed SIZE_BITS = MEDIUM_SIZE|SMALL_SIZE TYPE_BITS = SIZE_BITS|HIT_FLAG ;flags constants: UFO_LEFT = %00000001 UFO_DIR_FLAGS = %00000110 COLLISION_FLAG = %00001000 FIRE_FLAG = %00010000 UFO_FLAG = %00100000 SELECT_FLAG = %01000000 PLAYER2_FLAG = %10000000 ;flags2 constants: GAME_OVER = %00000001 KILL_FLAG = %00000010 HYPERSPACE_FLAG = %00000100 SHIELD_FLAG = %01000000 FLIP_FLAG = %10000000 ;game constants: BONUS_BITS = %110 FEATURE_BITS = %11000 TWO_PLAYERS = $20 ;soundBits constants: SOUND_KILL = $01 SOUND_THRUST = $02 SOUND_UFO = $08 SOUND_ENEMY = $10 ;lifesDir constants: DIR_MASK = %1111 LIFES_MASK = %11110000 NUM_ASTEROIDS_2 = 9 ; size for 9 asteroids in up and down list each, ; but only 7 are allowed (one is used for wrapping ; asteroids and one is wasted for marking the end ; of the list Y_ILLEGAL = $e0 ; marks an empty slot in asteroid list ;=============================================================================== ; Z P - V A R I A B L E S ;=============================================================================== game = $80 ; currently selected game randomLo = $81 randomHi = $82 ;--------------------------------------- ; all three lists are divided into two equally sized parts, ; one for up and one for down moving asteroids yPosLst = $83 ;..$94 $e0 means end of list xPosLst = $95 ;..$a6 stored as hmove/delay/LR (mmmmdddl) flagLst = $a7 ;..$b8 asteroids flags ;--------------------------------------- frameCnt = $b9 frameCntHi = $ba gameSpeed = $bb ; contains two counters, which determine ; horizontal asteroid speed ;--------------------------------------- player1 = $bc ;..$be lifesDir = player1 ; lllldddd scoreHigh = player1+1 scoreLow = player1+2 player2 = $bf ;..$c1 lifesDir2 = player2 ; lllldddd ;--------------------------------------- asteroidHit = $c2 ; remember that an asteroid has been hit (!=0) ;--------------------------------------- soundTimer0 = $c3 soundTimer1 = $c4 soundBits = $c5 ;--------------------------------------- ofsExpl = $c6 flags = $c7 ; flags2 = $c8 ;--------------------------------------- xShip = $c9 ; stored as HMove/Delay yShip = $ca ;--------------------------------------- speedLst = $cb ;..$d0 speedHiLst = speedLst speedHiX = speedHiLst speedHiY = speedHiLst+1 speedMidLst = speedLst+2 speedMidX = speedMidLst speedMidY = speedMidLst+1 speedLoLst = speedLst+4 speedLoX = speedLoLst speedLoY = speedLoLst+1 ;--------------------------------------- xUFO = $d1 yUFO = $d2 ;--------------------------------------- xShotLst = $d3 ;..$d5 xShot1 = xShotLst xShot2 = xShotLst+1 xShotUfo = xShotLst+2 yShotLst = $d6 ;..$d8 yShot1 = yShotLst yShot2 = yShotLst+1 yShotUfo = yShotLst+2 dirShotLst = $d9 ;..$db dirShot1 = dirShotLst dirShot2 = dirShotLst+1 dirShotUfo = dirShotLst+2 ;--------------------------------------- lwrBound = $dc uprBound = $dd ;--------------------------------------- ftrTimer = $de ; used for feature timing yShipNew = $df ssColor = $e0 cxTimer = $e1 ; shedules collison detections ;$e1 %UUxxxxUU lastDir = cxTimer ; using bits 3 and 4 for last direction jmpVec1 = $e3 ; ..$e4 ;--------------------------------------- ; shared variables for asteroids kernel: jmpVec2 = $e5 ; ..$e6 coarseMove0 = $e7 coarseMove1 = $e8 fineMove0 = $e9 fineMove1 = $ea ptr1 = $eb ; ..$ec ptr2 = $ed ; ..$ee ptr3 = $ef ; ..$f0 ptr4 = $f1 ; ..$f2 tmpVarA = $f3 tmpVarB = $f4 astType0 = $f8 astType1 = $f9 ;------------------- ; shared variables for objects kernel: ptrEnemy = $e6 ; ..$e7 ballCol = $e8 ; shipCol = $e9 ; enemyCol = $ea ; vDelP0Krnl = $eb vDelP1Krnl = $ec ; vertical delay for UFO/sattelite ; (never set, always enabled!) moveBits = vDelP1Krnl ptrShip = $ed ; ..$ee yShipKrnl = $ef ptrShipHlp = $f1 ptrEnemyHlp = $f2 tmpVar = $f2 ;--------------------------------------- bswVec = $f7 ; jmp vector used for bankswitching ;=============================================================================== ; R O M - C O D E (Bank 0) ;=============================================================================== ORG $d000 Ld000: jmp START1 ; 3 EndXPosP1: sta WSYNC ; 3 EndXPosP1a: sta HMOVE ; 3 sta GRP1 ; 3 stx NUSIZ1 ; 3 jmp (jmpVec1) ; 5 XPosP0_r/l ; the positioning routines are really "using" a *lot* of ROM! XPosP0_r SUBROUTINE ; @14 nop ; 2 php ; 3 plp ; 4 nop ; 2 nop ; 2 lda fineMove0 ; 3 sta HMCLR ; 3 sta HMP0 ; 3 @36 lda #Zero0 ; 2 sta .ptrDigits+1 ; 3 lda #OverScan ; 2 sta bswVec+1 ; 3 jmp SwitchBank1 ; 3 START0: lda #START1 ; 2 sta bswVec+1 ; 3 jmp SwitchBank1 ; 3 align 256, 0 XMoveObj SUBROUTINE ; a = number of pixel to move ; x = object-idx .tmpId = $f4 ldy xPosLst,x ; 4 stx .tmpId ; 3 tax ; 2 bcs .loopLeft ; 2³ .loopRight: lda XMoveRightTbl,y ; 4 tay ; 2 dex ; 2 bne .loopRight ; 2³ beq .exitRight ; 3 .loopLeft: lda XMoveLeftTbl,y ; 4 tay ; 2 dex ; 2 bne .loopLeft ; 2³ .exitRight: ldx .tmpId ; 3 sta xPosLst,x ; 4 ldy #>XMoveObjRTS ; 2 sty bswVec+1 ; 3 ldy #RetHMSizeTbl0 ; 2 sty bswVec+1 ; 3 ldy #RetHMSizeTbl1 ; 2 sty bswVec+1 ; 3 ldy #Col0 ; 2 sta $f5 ; 3 sta $f7 ; 3 sta $f9 ; 3 sta $fb ; 3 sta $fd ; 3 sta $ff ; 3 lda #StartMain ; 2 sta bswVec+1 ; 3 jmp SwitchBank1 ; 3 IF GARBAGE IF NTSC .byte $b4, $5b, $74, $3b, $34, $bb, $44, $bb .byte $04, $bb, $4b, $b4, $4b, $be, $4b, $bc .byte $4f, $b5, $45, $ba, $44, $bb, $46, $bb .byte $44, $b9, $b4, $4b, $b4, $4b, $b4, $4b .byte $b4, $4b, $b4, $5b, $b4, $db, $f4, $7b .byte $b4, $ab, $4f, $ba, $4a, $b5, $44, $b3 .byte $4c, $bb, $4c, $b9, $44, $bb, $44, $bb .byte $44, $bb, $bb, $45, $bb, $44, $bb, $44 .byte $bb, $44, $bb, $49, $ba, $43, $bc, $0b .byte $f0, $4b, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $bb, $44, $bb, $44, $bb, $44 .byte $bb, $44, $bb, $45, $bb, $05, $ba, $57 .byte $b5, $43, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $bb, $44, $bb, $44, $bb, $44 .byte $bb, $45, $b9, $47, $b9, $47, $f9, $42 .byte $b8, $4b, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $bb, $44, $bb, $44, $ba, $47 .byte $ba, $47, $bf, $47, $b8, $4b, $b4, $43 .byte $b4, $43, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $bb, $44, $bb, $44, $bb, $44 .byte $bb, $44, $bb, $46, $b1, $47, $ba, $47 .byte $be, $44, $44, $bb, $44, $3b, $44, $bb .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $bb, $44, $ba, $47, $be, $47 .byte $bf, $4e, $ba, $43, $90, $43, $b4, $1b .byte $6c, $89, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $bb, $44, $bb, $44, $bb, $45 .byte $ba, $47, $b5, $0b, $bc, $4f, $bc, $4b .byte $b4, $4b, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $bb, $44, $bb, $45, $ba, $45 .byte $bb, $40, $be, $4f, $b9, $47, $b4, $43 .byte $9c, $5b, $cc, $bb, $44, $bb, $44, $bb .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb ELSE .byte $b4, $5b, $74, $3b, $34, $bb, $44, $3b .byte $04, $bb, $4b, $b4, $4b, $be, $4b, $bc .byte $4f, $b5, $45, $ba, $44, $bb, $44, $bb .byte $44, $b9, $b4, $4b, $b4, $4b, $b4, $4b .byte $b4, $4b, $b4, $5b, $b4, $db, $f4, $7b .byte $b4, $ab, $4f, $ba, $4a, $b5, $44, $b3 .byte $4c, $bb, $4c, $b9, $44, $bb, $44, $bb .byte $44, $bb, $bb, $45, $bb, $44, $bb, $44 .byte $bb, $44, $bb, $09, $ba, $43, $bc, $0b .byte $f0, $4b, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $bb, $44, $bb, $44, $bb, $44 .byte $bb, $44, $bb, $45, $bb, $05, $ba, $57 .byte $b5, $43, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $ba, $44, $bb, $44, $bb, $44 .byte $bb, $45, $b9, $47, $b9, $47, $f9, $42 .byte $b8, $4b, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $bb, $44, $bb, $44, $ba, $47 .byte $ba, $47, $bf, $47, $b8, $4b, $b4, $43 .byte $b4, $43, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $bb, $44, $bb, $44, $bb, $44 .byte $bb, $44, $bb, $46, $b1, $47, $ba, $47 .byte $be, $44, $44, $bb, $44, $3b, $44, $bb .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $bb, $45, $b8, $47, $be, $47 .byte $be, $4e, $ba, $43, $90, $43, $b4, $1b .byte $6c, $89, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $bb, $44, $bb, $44, $bb, $45 .byte $ba, $47, $b5, $0b, $bc, $4f, $bc, $4b .byte $b4, $4b, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $bb, $44, $bb, $45, $ba, $45 .byte $bb, $40, $be, $4f, $b9, $47, $b4, $43 .byte $9c, $5b, $cc, $bb, $44, $bb, $44, $bb .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb ENDIF ELSE align 256, 0 .byte 0 align 256, 0 ENDIF ELSE ORG $dd00, 0 ENDIF Zero0: .byte %11100000 ; |XXX | $dd00 .byte %10100000 ; |X X | .byte %10100000 ; |X X | .byte %10100000 ; |X X | .byte %11100000 ; |XXX | .byte %11100000 ; |XXX | .byte %01000000 ; | X | .byte %01000000 ; | X | .byte %01100000 ; | XX | .byte %01000000 ; | X | .byte %11100000 ; |XXX | .byte %00100000 ; | X | .byte %11100000 ; |XXX | .byte %10000000 ; |X | .byte %11100000 ; |XXX | .byte %11100000 ; |XXX | .byte %10000000 ; |X | .byte %11000000 ; |XX | .byte %10000000 ; |X | .byte %11100000 ; |XXX | .byte %10000000 ; |X | .byte %10000000 ; |X | .byte %11100000 ; |XXX | .byte %10100000 ; |X X | .byte %10100000 ; |X X | .byte %11100000 ; |XXX | .byte %10000000 ; |X | .byte %11100000 ; |XXX | .byte %00100000 ; | X | .byte %11100000 ; |XXX | .byte %11100000 ; |XXX | .byte %10100000 ; |X X | .byte %11100000 ; |XXX | .byte %00100000 ; | X | .byte %00100000 ; | X | .byte %10000000 ; |X | .byte %10000000 ; |X | .byte %10000000 ; |X | .byte %10000000 ; |X | .byte %11100000 ; |XXX | .byte %11100000 ; |XXX | .byte %10100000 ; |X X | .byte %11100000 ; |XXX | .byte %10100000 ; |X X | .byte %11100000 ; |XXX | .byte %10000000 ; |X | .byte %10000000 ; |X | .byte %11100000 ; |XXX | .byte %10100000 ; |X X | .byte %11100000 ; |XXX | Zero1: .byte %00001110 ; | XXX | $dd32 .byte %00001010 ; | X X | .byte %00001010 ; | X X | .byte %00001010 ; | X X | .byte %00001110 ; | XXX | One1: .byte %00001110 ; | XXX | .byte %00000100 ; | X | .byte %00000100 ; | X | .byte %00000110 ; | XX | .byte %00000100 ; | X | Two1: .byte %00001110 ; | XXX | .byte %00000010 ; | X | .byte %00001110 ; | XXX | .byte %00001000 ; | X | .byte %00001110 ; | XXX | .byte %00001110 ; | XXX | .byte %00001000 ; | X | .byte %00001100 ; | XX | .byte %00001000 ; | X | .byte %00001110 ; | XXX | .byte %00001000 ; | X | .byte %00001000 ; | X | .byte %00001110 ; | XXX | .byte %00001010 ; | X X | .byte %00001010 ; | X X | .byte %00001110 ; | XXX | .byte %00001000 ; | X | .byte %00001110 ; | XXX | .byte %00000010 ; | X | .byte %00001110 ; | XXX | .byte %00001110 ; | XXX | .byte %00001010 ; | X X | .byte %00001110 ; | XXX | .byte %00000010 ; | X | .byte %00000010 ; | X | .byte %00001000 ; | X | .byte %00001000 ; | X | .byte %00001000 ; | X | .byte %00001000 ; | X | .byte %00001110 ; | XXX | .byte %00001110 ; | XXX | .byte %00001010 ; | X X | .byte %00001110 ; | XXX | .byte %00001010 ; | X X | .byte %00001110 ; | XXX | .byte %00001000 ; | X | .byte %00001000 ; | X | .byte %00001110 ; | XXX | .byte %00001010 ; | X X | .byte %00001110 ; | XXX | Zero2: .byte %01110000 ; | XXX | $dd64 .byte %01010000 ; | X X | .byte %01010000 ; | X X | .byte %01010000 ; | X X | .byte %01110000 ; | XXX | .byte %01110000 ; | XXX | .byte %00100000 ; | X | .byte %00100000 ; | X | .byte %01100000 ; | XX | .byte %00100000 ; | X | .byte %01110000 ; | XXX | .byte %01000000 ; | X | .byte %01110000 ; | XXX | .byte %00010000 ; | X | .byte %01110000 ; | XXX | .byte %01110000 ; | XXX | .byte %00010000 ; | X | .byte %00110000 ; | XX | .byte %00010000 ; | X | .byte %01110000 ; | XXX | .byte %00010000 ; | X | .byte %00010000 ; | X | .byte %01110000 ; | XXX | .byte %01010000 ; | X X | .byte %01010000 ; | X X | .byte %01110000 ; | XXX | .byte %00010000 ; | X | .byte %01110000 ; | XXX | .byte %01000000 ; | X | .byte %01110000 ; | XXX | .byte %01110000 ; | XXX | .byte %01010000 ; | X X | .byte %01110000 ; | XXX | .byte %01000000 ; | X | .byte %01000000 ; | X | .byte %00010000 ; | X | .byte %00010000 ; | X | .byte %00010000 ; | X | .byte %00010000 ; | X | .byte %01110000 ; | XXX | .byte %01110000 ; | XXX | .byte %01010000 ; | X X | .byte %01110000 ; | XXX | .byte %01010000 ; | X X | .byte %01110000 ; | XXX | .byte %00010000 ; | X | .byte %00010000 ; | X | .byte %01110000 ; | XXX | .byte %01010000 ; | X X | .byte %01110000 ; | XXX | Zero3: .byte %00000111 ; | XXX| $dd96 .byte %00000101 ; | X X| .byte %00000101 ; | X X| .byte %00000101 ; | X X| .byte %00000111 ; | XXX| .byte %00000111 ; | XXX| .byte %00000010 ; | X | .byte %00000010 ; | X | .byte %00000110 ; | XX | .byte %00000010 ; | X | .byte %00000111 ; | XXX| .byte %00000100 ; | X | .byte %00000111 ; | XXX| .byte %00000001 ; | X| .byte %00000111 ; | XXX| .byte %00000111 ; | XXX| .byte %00000001 ; | X| .byte %00000011 ; | XX| .byte %00000001 ; | X| .byte %00000111 ; | XXX| .byte %00000001 ; | X| .byte %00000001 ; | X| .byte %00000111 ; | XXX| .byte %00000101 ; | X X| .byte %00000101 ; | X X| .byte %00000111 ; | XXX| .byte %00000001 ; | X| .byte %00000111 ; | XXX| .byte %00000100 ; | X | .byte %00000111 ; | XXX| .byte %00000111 ; | XXX| .byte %00000101 ; | X X| .byte %00000111 ; | XXX| .byte %00000100 ; | X | .byte %00000100 ; | X | .byte %00000001 ; | X| .byte %00000001 ; | X| .byte %00000001 ; | X| .byte %00000001 ; | X| .byte %00000111 ; | XXX| .byte %00000111 ; | XXX| .byte %00000101 ; | X X| .byte %00000111 ; | XXX| .byte %00000101 ; | X X| .byte %00000111 ; | XXX| .byte %00000001 ; | X| .byte %00000001 ; | X| .byte %00000111 ; | XXX| .byte %00000101 ; | X X| .byte %00000111 ; | XXX| Blank: LifesTbl1: .byte %00000000 ; | | $ddc8 .byte %00000000 ; | | $ddc9 .byte %00000000 ; | | $ddca .byte %00000000 ; | | $ddcb .byte %00000000 ; | | $ddcc IF ORIGINAL .byte %01111100 ; | XXXXX | $ddcd .byte %00111000 ; | XXX | $ddce .byte %00111000 ; | XXX | $ddcf .byte %00010000 ; | X | $ddd0 .byte %00010000 ; | X | $ddd1 .byte %01111100 ; | XXXXX | $ddd2 .byte %00111000 ; | XXX | $ddd3 .byte %00111000 ; | XXX | $ddd4 .byte %00010000 ; | X | $ddd5 .byte %00010000 ; | X | $ddd6 ELSE .byte %01101100 ; | XX XX | $ddcd .byte %00111000 ; | XXX | $ddce .byte %00101000 ; | X X | $ddcf .byte %00010000 ; | X | $ddd0 .byte %00010000 ; | X | $ddd1 .byte %01101100 ; | XX XX | $ddd2 .byte %00111000 ; | XXX | $ddd3 .byte %00101000 ; | X X | $ddd4 .byte %00010000 ; | X | $ddd5 .byte %00010000 ; | X | $ddd6 ENDIF LifesTbl2: .byte %00000000 ; | | $ddd7 .byte %00000000 ; | | $ddd8 .byte %00000000 ; | | $ddd9 .byte %00000000 ; | | $ddda .byte %00000000 ; | | $dddb .byte %00000000 ; | | $dddc .byte %00000000 ; | | $dddd .byte %00000000 ; | | $ddde .byte %00000000 ; | | $dddf .byte %00000000 ; | | $dde0 IF ORIGINAL .byte %01111100 ; | XXXXX | $dde1 .byte %00111000 ; | XXX | $dde2 .byte %00111000 ; | XXX | $dde3 .byte %00010000 ; | X | $dde4 .byte %00010000 ; | X | $dde5 ELSE .byte %01101100 ; | XX XX | $dde1 .byte %00111000 ; | XXX | $dde2 .byte %00101000 ; | X X | $dde3 .byte %00010000 ; | X | $dde4 .byte %00010000 ; | X | $dde5 ENDIF IF GARBAGE .byte $b8, $4b, $be, $03, $bc, $0b, $fc, $cb .byte $54, $0b, $44, $bb, $54, $bb, $44, $bb .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb ELSE align 256, 0 ENDIF HMSizeTbl: ; 8 ist used as corect flag for wrapping asteroids; IF ORIGINAL .byte $00|$8|DOUBLE_SIZE ; $de00 large asteroid #1 .byte $00|$8|DOUBLE_SIZE .byte $10|$8|DOUBLE_SIZE .byte $00|$0|DOUBLE_SIZE .byte $00|$0|DOUBLE_SIZE .byte $00|$0|DOUBLE_SIZE .byte $00|$0|DOUBLE_SIZE .byte $f0|$0|DOUBLE_SIZE .byte $10|$8|DOUBLE_SIZE .byte $f0|$0|DOUBLE_SIZE .byte $10|$8|DOUBLE_SIZE .byte $f0|$0|DOUBLE_SIZE .byte $00|$8|DOUBLE_SIZE .byte $00|$8|DOUBLE_SIZE .byte $00|$8|DOUBLE_SIZE .byte $00 ELSE .byte $00|$8|DOUBLE_SIZE ; $de00 .byte $00|$8|DOUBLE_SIZE .byte $00|$8|DOUBLE_SIZE ; .byte $10|$8|DOUBLE_SIZE .byte $00|$0|DOUBLE_SIZE .byte $00|$0|DOUBLE_SIZE .byte $00|$0|DOUBLE_SIZE .byte $00|$0|DOUBLE_SIZE .byte $f0|$0|DOUBLE_SIZE .byte $10|$8|DOUBLE_SIZE .byte $f0|$0|DOUBLE_SIZE .byte $10|$8|DOUBLE_SIZE .byte $f0|$0|DOUBLE_SIZE .byte $00|$8|DOUBLE_SIZE .byte $00|$8|DOUBLE_SIZE .byte $10|$8|DOUBLE_SIZE .byte $00 ENDIF .byte $00|$8|DOUBLE_SIZE ; $de10 large asteroid #2 .byte $00|$8|DOUBLE_SIZE .byte $00|$8|DOUBLE_SIZE .byte $00|$8|DOUBLE_SIZE .byte $00|$8|DOUBLE_SIZE .byte $00|$8|DOUBLE_SIZE .byte $00|$8|DOUBLE_SIZE .byte $00|$8|DOUBLE_SIZE .byte $00|$8|DOUBLE_SIZE .byte $10|$8|DOUBLE_SIZE .byte $00|$0|DOUBLE_SIZE .byte $00|$0|DOUBLE_SIZE .byte $f0|$0|DOUBLE_SIZE .byte $00|$8|DOUBLE_SIZE .byte $00|$8|DOUBLE_SIZE .byte $00 .byte $08 ; $de20 medium asteroid .byte $08 .byte $08 .byte $08 .byte $08 .byte $08 .byte $08 .byte $00 IF GARBAGE IF NTSC .byte $bc, $43, $fc, $4b, $bc, $4b, $f4, $0b ELSE .byte $bc, $43, $fc, $4b, $bc, $0b, $b4, $0b ENDIF ELSE ds 8, 0 ENDIF .byte $08 ; $de30 small asteroid .byte $08 .byte $08 .byte $08 .byte $00 IF GARBAGE .byte $bb, $44, $bb, $44, $bb, $44, $bb, $44 .byte $bb, $44, $bb ELSE ds 11, 0 ENDIF .byte $08 ; $de40 large explosion .byte $08 .byte $08 .byte $08 .byte $08 .byte $08 .byte $08 .byte $08 .byte $08 .byte $08 .byte $08 .byte $00 IF GARBAGE .byte $3c, $4b, $b4, $0b ELSE ds 4, 0 ENDIF .byte $08 ; $de50 .byte $08 .byte $08 .byte $08 .byte $08 .byte $08 .byte $08 .byte $08 .byte $08 .byte $08 .byte $08 .byte $00 IF GARBAGE .byte $44, $bb, $44, $bb ELSE ds 4, 0 ENDIF .byte $08 ; $de60 .byte $08 .byte $08 .byte $08 .byte $08 .byte $08 .byte $08 .byte $08 .byte $00 IF GARBAGE IF NTSC .byte $45, $ba, $43, $be, $4b, $b2, $4b ELSE .byte $45, $ba, $43, $be, $4a, $be, $4b ENDIF ELSE ds 7, 0 ENDIF .byte $08 ; $de70 .byte $08 .byte $08 .byte $08 .byte $00 ColTbl: ; asteroid colors: IF NTSC .byte WHITE-2 .byte RED+4 .byte BLUE2+$c .byte YELLOW+8 .byte BROWN+6 .byte MAGENTA+6 .byte BLUE1+6 .byte OCHRE_GREEN+6 ELSE .byte BLUE2+2 .byte MAGENTA+4 .byte BROWN+6 .byte MAGENTA2+6 .byte CYAN+8 .byte BROWN+$a .byte RED+$c .byte WHITE ENDIF ; tables for displaying the remaining ships: LifesOfsTbl: .byte $04, $04, $09, $0e, $0e, $0e, $0e, $0e LifesHMoveTbl: .byte $55, $55, $25, $bc, $34, $cd, $45, $45 LifesNusizTbl: .byte ONE_COPY <<4|ONE_COPY .byte ONE_COPY <<4|ONE_COPY .byte ONE_COPY <<4|ONE_COPY .byte ONE_COPY <<4|ONE_COPY .byte ONE_COPY <<4|TWO_COPIES .byte TWO_COPIES <<4|TWO_COPIES .byte TWO_COPIES <<4|THREE_COPIES .byte THREE_COPIES<<4|THREE_COPIES LifesDelayTbl: .byte 0, 0, 2, 1, 1, 0, 0, 0 IF GARBAGE IF NTSC .byte $bb, $44, $bb, $bb, $44, $bb, $45, $bb .byte $44, $ba, $41, $bf, $01, $b0, $43, $bc .byte $4b, $fc, $c3, $44, $bb, $44, $bb, $44 .byte $bb, $44, $bb, $44, $bb, $44, $bb, $44 .byte $bb, $44, $bb, $bb, $44, $bb, $44, $bb .byte $45, $ba, $45, $ba, $45, $be, $23, $f4 .byte $4b, $bc, $4b, $44, $bb, $44, $bb, $44 .byte $bb, $44, $bb, $44, $bb, $44, $bb, $44 .byte $bb, $44, $bb, $bb, $44, $bb, $44, $bb .byte $45, $bb, $45, $be, $43, $be, $43, $bc .byte $0b, $b4, $4b, $44, $bb, $44, $bb, $44 .byte $bb, $44, $bb, $44, $bb, $44, $bb, $44 .byte $bb, $44, $bb ELSE .byte $bb, $44, $bb, $bb, $44, $bb, $45, $bb .byte $44, $ba, $41, $bf, $01, $b8, $43, $bc .byte $4b, $fc, $c3, $44, $bb, $44, $bb, $44 .byte $bb, $44, $bb, $44, $bb, $44, $bb, $44 .byte $bb, $44, $bb, $bb, $44, $bb, $44, $bb .byte $45, $ba, $45, $ba, $45, $be, $23, $f4 .byte $4b, $bc, $4b, $44, $bb, $44, $bb, $44 .byte $bb, $44, $bb, $44, $bb, $44, $bb, $44 .byte $bb, $44, $bb, $bb, $44, $bb, $44, $bb .byte $45, $bb, $45, $be, $43, $be, $43, $bc .byte $0b, $b4, $4b, $44, $bb, $44, $bb, $44 .byte $bb, $44, $bb, $44, $bb, $44, $bb, $44 .byte $bb, $44, $bb ENDIF ELSE align 256, 0 ENDIF Asteroids: IF ORIGINAL .byte %00000000 ; | | $df00 .byte %00010000 ; | X | .byte %00011100 ; | XXX | .byte %00011110 ; | XXXX | .byte %00111110 ; | XXXXX | .byte %00111111 ; | XXXXXX| .byte %01111111 ; | XXXXXXX| .byte %11111111 ; |XXXXXXXX| .byte %01111111 ; | XXXXXXX| .byte %11111111 ; |XXXXXXXX| .byte %01111111 ; | XXXXXXX| .byte %00111110 ; | XXXXX | .byte %00111110 ; | XXXXX | .byte %00011100 ; | XXX | .byte %00001100 ; | XX | IF GARBAGE .byte $43 ELSE .byte 0 ENDIF .byte %00000000 ; | | $df10 .byte %00111100 ; | XXXX | .byte %01111110 ; | XXXXXX | .byte %01111111 ; | XXXXXXX| .byte %00111111 ; | XXXXXX| .byte %01111111 ; | XXXXXXX| .byte %11111111 ; |XXXXXXXX| .byte %11111110 ; |XXXXXXX | .byte %11111110 ; |XXXXXXX | .byte %01111111 ; | XXXXXXX| .byte %01111111 ; | XXXXXXX| .byte %00111111 ; | XXXXXX| .byte %00111110 ; | XXXXX | .byte %00111110 ; | XXXXX | .byte %00011100 ; | XXX | IF GARBAGE .byte $bb ELSE .byte 0 ENDIF .byte %00011000 ; | XX | $df20 .byte %00111100 ; | XXXX | .byte %01111110 ; | XXXXXX | .byte %11111111 ; |XXXXXXXX| .byte %11111111 ; |XXXXXXXX| .byte %01111110 ; | XXXXXX | .byte %00001100 ; | XX | ELSE .byte %00000000 ; | | $df00 .byte %00001000 ; | X | .byte %00010100 ; | X X | .byte %00010010 ; | X X | .byte %00100010 ; | X X | .byte %00100001 ; | X X| .byte %01000001 ; | X X| .byte %10000001 ; |X X| .byte %01000001 ; | X X| .byte %10000001 ; |X X| .byte %01100001 ; | XX X| .byte %00100010 ; | X X | .byte %00100010 ; | X X | .byte %00010100 ; | X X | .byte %00001100 ; | XX | IF GARBAGE .byte $43 ELSE .byte 0 ENDIF .byte %00000000 ; | | $df10 .byte %00111000 ; | XXX | .byte %01000110 ; | X XX | .byte %01000001 ; | X X| .byte %00100001 ; | X X| .byte %01000001 ; | X X| .byte %10000010 ; |X X | .byte %10000100 ; |X X | .byte %10000010 ; |X X | .byte %01000010 ; | X X | .byte %01000001 ; | X X| .byte %00100001 ; | X X| .byte %00100010 ; | X X | .byte %00100010 ; | X X | .byte %00011100 ; | XXX | IF GARBAGE .byte $bb ELSE .byte 0 ENDIF .byte %00111000 ; | XXX | $df20 .byte %01000100 ; | X X | .byte %01000010 ; | X X | .byte %10000001 ; |X X| .byte %10000001 ; |X X| .byte %01110010 ; | XXX X | .byte %00001100 ; | XX | ENDIF IF GARBAGE .byte $43, $be, $4b, $bc, $4b, $b4, $5b, $b4 .byte $5b ELSE ORG $df30 ENDIF IF ORIGINAL .byte %01100000 ; | XX | $df30 .byte %11110000 ; |XXXX | .byte %11110000 ; |XXXX | .byte %00100000 ; | X | ELSE .byte %01100000 ; | XX | $df30 .byte %10010000 ; |X X | .byte %11010000 ; |XX X | .byte %00100000 ; | X | ENDIF IF GARBAGE .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $44, $bb ELSE ORG $df40 ENDIF ; exploding asteroids: .byte %10100000 ; |X X | $df40 .byte %00000100 ; | X | .byte %01000000 ; | X | .byte %00001001 ; | X X| .byte %00100000 ; | X | .byte %00000000 ; | | .byte %10001000 ; |X X | .byte %00000001 ; | X| .byte %00010000 ; | X | .byte %01000000 ; | X | .byte %00010001 ; | X X| IF GARBAGE .byte $43, $b4, $4b, $b4, $4b ELSE ds 5, 0 ENDIF .byte %01001000 ; | X X | $df50 .byte %00000010 ; | X | .byte %00100000 ; | X | .byte %10001000 ; |X X | .byte %00000001 ; | X| .byte %01000000 ; | X | .byte %00010100 ; | X X | .byte %01000000 ; | X | .byte %00000000 ; | | .byte %00100001 ; | X X| .byte %10000100 ; |X X | IF GARBAGE .byte $bb, $44, $bb, $44, $bb ELSE ds 5, 0 ENDIF .byte %01010000 ; | X X | $df60 .byte %00000010 ; | X | .byte %00100000 ; | X | .byte %10000001 ; |X X| .byte %00000100 ; | X | .byte %01000000 ; | X | .byte %00010000 ; | X | .byte %01000001 ; | X X| IF GARBAGE .byte $bc, $41, $b4, $43, $b6, $49, $b0, $5b ELSE ds 8, 0 ENDIF .byte %01000000 ; | X | $df70 .byte %00010000 ; | X | $df71 .byte %10000000 ; |X | $df72 .byte %00100000 ; | X | $df73 Ship: IF ORIGINAL .byte %00010000 ; | X | $df74 .byte %00010000 ; | X | $df75 .byte %00111000 ; | XXX | $df76 .byte %00111000 ; | XXX | $df77 .byte %01111100 ; | XXXXX | $df78 Ldf79: .byte %11111111 ; |XXXXXXXX| $df79 .byte %00100000 ; | X | $df7a .byte %00110000 ; | XX | $df7b .byte %00111000 ; | XXX | $df7c .byte %00111100 ; | XXXX | $df7d .byte %00110000 ; | XX | $df7e .byte %11111111 ; |XXXXXXXX| $df7f .byte %01000000 ; | X | $df80 .byte %00110000 ; | XX | $df81 .byte %00111100 ; | XXXX | $df82 .byte %00011000 ; | XX | $df83 .byte %00010000 ; | X | $df84 .byte %11111111 ; |XXXXXXXX| $df85 .byte %00000000 ; | | $df86 .byte %01000000 ; | X | $df87 .byte %00111110 ; | XXXXX | $df88 .byte %00011100 ; | XXX | $df89 .byte %00001100 ; | XX | $df8a .byte %11111111 ; |XXXXXXXX| $df8b .byte %00000100 ; | X | $df8c .byte %00011100 ; | XXX | $df8d .byte %11111100 ; |XXXXXX | $df8e .byte %00011100 ; | XXX | $df8f .byte %00000100 ; | X | $df90 .byte %11111111 ; |XXXXXXXX| $df91 .byte %00001100 ; | XX | $df92 .byte %00011100 ; | XXX | $df93 .byte %00111110 ; | XXXXX | $df94 .byte %01000000 ; | X | $df95 .byte %00000000 ; | | $df96 .byte %11111111 ; |XXXXXXXX| $df97 .byte %00010000 ; | X | $df98 .byte %00011000 ; | XX | $df99 .byte %00111100 ; | XXXX | $df9a .byte %00110000 ; | XX | $df9b .byte %01000000 ; | X | $df9c .byte %11111111 ; |XXXXXXXX| $df9d .byte %00110000 ; | XX | $df9e .byte %00111100 ; | XXXX | $df9f .byte %00111000 ; | XXX | $dfa0 .byte %00110000 ; | XX | $dfa1 .byte %00100000 ; | X | $dfa2 .byte %11111111 ; |XXXXXXXX| $dfa3 .byte %01111100 ; | XXXXX | $dfa4 .byte %00111000 ; | XXX | $dfa5 .byte %00111000 ; | XXX | $dfa6 .byte %00010000 ; | X | $dfa7 .byte %00010000 ; | X | $dfa8 ELSE .byte %00010000 ; | X | $df74 .byte %00010000 ; | X | $df75 .byte %00101000 ; | XXX | $df76 .byte %00111000 ; | XXX | $df77 .byte %01101100 ; | XXXXX | $df78 Ldf79: .byte %11111111 ; |XXXXXXXX| $df79 .byte %00100000 ; | X | $df7a .byte %00110000 ; | XX | $df7b .byte %00101000 ; | XXX | $df7c .byte %00101100 ; | XXXX | $df7d .byte %00110000 ; | XX | $df7e .byte %11111111 ; |XXXXXXXX| $df7f .byte %01000000 ; | X | $df80 .byte %00110000 ; | XX | $df81 .byte %00101100 ; | XXXX | $df82 .byte %00011000 ; | XX | $df83 .byte %00010000 ; | X | $df84 .byte %11111111 ; |XXXXXXXX| $df85 .byte %00000000 ; | | $df86 .byte %01000000 ; | X | $df87 .byte %00111110 ; | XXXXX | $df88 .byte %00010100 ; | XXX | $df89 .byte %00001100 ; | XX | $df8a .byte %11111111 ; |XXXXXXXX| $df8b .byte %00000100 ; | X | $df8c .byte %00011100 ; | XXX | $df8d .byte %11101000 ; |XXXXXX | $df8e .byte %00011100 ; | XXX | $df8f .byte %00000100 ; | X | $df90 .byte %11111111 ; |XXXXXXXX| $df91 .byte %00001100 ; | XX | $df92 .byte %00010100 ; | XXX | $df93 .byte %00111110 ; | XXXXX | $df94 .byte %01000000 ; | X | $df95 .byte %00000000 ; | | $df96 .byte %11111111 ; |XXXXXXXX| $df97 .byte %00010000 ; | X | $df98 .byte %00011000 ; | XX | $df99 .byte %00101100 ; | XXXX | $df9a .byte %00110000 ; | XX | $df9b .byte %01000000 ; | X | $df9c .byte %11111111 ; |XXXXXXXX| $df9d .byte %00110000 ; | XX | $df9e .byte %00101100 ; | XXXX | $df9f .byte %00101000 ; | XXX | $dfa0 .byte %00110000 ; | XX | $dfa1 .byte %00100000 ; | X | $dfa2 .byte %11111111 ; |XXXXXXXX| $dfa3 .byte %01101100 ; | XXXXX | $dfa4 .byte %00111000 ; | XXX | $dfa5 .byte %00101000 ; | XXX | $dfa6 .byte %00010000 ; | X | $dfa7 .byte %00010000 ; | X | $dfa8 ENDIF .byte %11111111 ; |XXXXXXXX| $dfa9 Explosion: .byte %00010000 ; | X | $dfaa .byte %00000010 ; | X | $dfab .byte %00001000 ; | X | $dfac .byte %00100010 ; | X X | $dfad .byte %00001000 ; | X | $dfae .byte %11111111 ; |XXXXXXXX| $dfaf .byte %00001000 ; | X | $dfb0 .byte %00010000 ; | X | $dfb1 .byte %10000000 ; |X | $dfb2 .byte %00000100 ; | X | $dfb3 .byte %10100010 ; |X X X | $dfb4 .byte %11111111 ; |XXXXXXXX| $dfb5 .byte %00100000 ; | X | $dfb6 .byte %10000001 ; |X X| $dfb7 .byte %00100010 ; | X X | $dfb8 .byte %00010000 ; | X | $dfb9 .byte %00000100 ; | X | $dfba .byte %11111111 ; |XXXXXXXX| $dfbb Shield: .byte %00111000 ; | XXX | $dfbc .byte %01000100 ; | X X | $dfbd .byte %01010100 ; | X X X | $dfbe .byte %01000100 ; | X X | $dfbf .byte %00111000 ; | XXX | $dfc0 .byte %11111111 ; |XXXXXXXX| $dfc1 UFO: IF ORIGINAL .byte %00010000 ; | X | $dfc2 .byte %01111100 ; | XXXXX | $dfc3 .byte %00111000 ; | XXX | $dfc4 .byte %11111111 ; |XXXXXXXX| $dfc5 Sattelite: .byte %00010000 ; | X | $dfc6 .byte %00111000 ; | XXX | $dfc7 .byte %11111110 ; |XXXXXXX | $dfc8 .byte %01111100 ; | XXXXX | $dfc9 .byte %00111000 ; | XXX | $dfca .byte %11111111 ; |XXXXXXXX| $dfcb ELSE .byte %00010000 ; | X | $dfc2 .byte %01101100 ; | XX XX | $dfc3 .byte %00111000 ; | XXX | $dfc4 .byte %11111111 ; |XXXXXXXX| $dfc5 Sattelite: .byte %00010000 ; | X | $dfc6 .byte %00101000 ; | X X | $dfc7 .byte %11000110 ; |XX XX | $dfc8 .byte %01000100 ; | X X | $dfc9 .byte %00111000 ; | XXX | $dfca .byte %11111111 ; |XXXXXXXX| $dfcb ENDIF IF GARBAGE IF NTSC .byte $b4, $cb, $74, $8b, $44, $bb, $44, $bb .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $44, $bb, $bb, $44, $bb, $44 .byte $bb, $44, $bb, $4c, $be, $43, $be, $40 .byte $b4, $49, $b6, $0b ELSE .byte $b4, $cb, $74, $8b, $44, $bb, $44, $bb .byte $44, $bb, $44, $bb, $44, $bb, $44, $bb .byte $44, $bb, $44, $bb, $bb, $44, $bb, $44 .byte $bb, $44, $bb, $4c, $be, $43, $be, $41 .byte $b4, $49, $b6, $0b ENDIF ELSE ORG $dff0 ENDIF SwitchBank1: sta BANK1 ; 4 jmp (bswVec) ; 5 IF GARBAGE IF NTSC .byte $44, $bb, $44, $b9 ELSE .byte $44, $bb, $44, $ff ENDIF ELSE ORG $dffa, 0 ENDIF .word START0, START0, START0 ;=============================================================================== ; R O M - C O D E (Bank 1) ;=============================================================================== ORG $e000 RORG $f000 Lf100 = $f100 OverScan: ldx #$ff ; 2 txs ; 2 IF NTSC lda #$24 ; 2 ELSE lda #$2c ; 2 ENDIF sta TIM64T ; 4 lda SWCHB ; 4 ror ; 2 ror ; 2 bcs .skipSelect ; 2³ bit game ; 3 bvs Lf035 ; 2³ lda game ; 3 ora #$40 ; 2 sta game ; 3 lda flags ; 3 ora #SELECT_FLAG ; 2 sta flags ; 3 lda flags2 ; 3 ora #GAME_OVER ; 2 sta flags2 ; 3 lda #Y_ILLEGAL ; 2 sta yShip ; 3 sta yUFO ; 3 lda #$00 ; 2 sta frameCnt ; 3 sta frameCntHi ; 3 sta lifesDir ; 3 sta lifesDir2 ; 3 Lf035: lda SWCHB ; 4 ror ; 2 lda frameCnt ; 3 and #$3f ; 2 bcs Lf041 ; 2³ and #$0f ; 2 Lf041: bne .noAdjust ; 2³ ; convert game number (extra values for child games!) inc game ; 5 lda game ; 3 ldx #4 ; 2 .loopAdjust: dex ; 2 bmi .noAdjust ; 2³ cmp AdjustFromTbl,x ; 4 bne .loopAdjust ; 2³ lda AdjustToTbl,x ; 4 sta game ; 3 .noAdjust: jmp .skipReset ; 3 .skipSelect: lda game ; 3 and #$bf ; 2 sta game ; 3 lda SWCHB ; 4 ror ; 2 bcs .skipReset ; 2³ ; start new game: lda #$00 ; 2 sta COLUBK ; 3 ldx #yPosLst ; 2 .loopClear: sta $00,x ; 4 inx ; 2 bne .loopClear ; 2³ lda #$40 ; 2 4 lifes sta lifesDir ; 3 sta lifesDir2 ; 3 IF NTSC lda #H_KERNEL/2-3 ; 2 ELSE lda #H_KERNEL/2-5 ; 2 ENDIF sta yShip ; 3 jmp StartNewGame ; 3 .skipReset: ; find first lower empty object-slot: ldx #0 ; 2 .loopLower: lda yPosLst,x ; 4 cmp #Y_ILLEGAL ; 2 beq .exitLower ; 2³ inx ; 2 bpl .loopLower ; 3 .exitLower: cpx #0 ; 2 beq .zero ; 2³ dex ; 2 .zero: stx lwrBound ; 3 ; find first upper empty object-slot: ldx #NUM_ASTEROIDS_2 ; 2 .loopUpper: lda yPosLst,x ; 4 cmp #Y_ILLEGAL ; 2 beq .exitUpper ; 2³ inx ; 2 bpl .loopUpper ; 3 .exitUpper: cpx #NUM_ASTEROIDS_2 ; 2 beq .max ; 2³ dex ; 2 .max: stx uprBound ; 3 ; check if lower or upper object-slots are used: ldx #0 ; 2 lda yPosLst,x ; 4 cmp #Y_ILLEGAL ; 2 bne .contLevel ; 2³ ldx #NUM_ASTEROIDS_2 ; 2 lda yPosLst,x ; 4 cmp #Y_ILLEGAL ; 2 bne .contLevel ; 2³ ; no more asteroids, start new level: jsr SetupAsteroids ; 6 jmp .endCollisions ; 3 .contLevel: lda asteroidHit ; 3 bne .cxAsteroids ; 2³+1 bit flags2 ; 3 shield enabled? bvs Lf0ce ; 2³ yes lda flags2 ; 3 ror ; 2 game over? bcs .endCollisionsJmp; 2³+1 yes lda yShip ; 3 cmp #Y_ILLEGAL ; 2 bne .checkCollisions ; 2³+1 lda ftrTimer ; 3 beq Lf0df ; 2³ Lf0ce: lda yUFO ; 3 cmp #Y_ILLEGAL ; 2 bne .checkCollisions ; 2³+1 lda dirShot1 ; 3 any shots? ora dirShot2 ; 3 ora dirShotUfo ; 3 bne .checkCollisions ; 2³+1 yes, jmp .endCollisions ; 3 Lf0df: lda flags2 ; 3 and #KILL_FLAG ; 2 ship killed? beq Lf0fd ; 2³ no lda yUFO ; 3 cmp #Y_ILLEGAL ; 2 bne .checkCollisions ; 2³+1 lda dirShotUfo ; 3 bne .checkCollisions ; 2³+1 ldx #0 ; 2 jsr CheckSpace ; 6 bne .endCollisionsJmp; 2³+1 ldx #NUM_ASTEROIDS_2 ; 2 jsr CheckSpace ; 6 bne .endCollisionsJmp; 2³+1 Lf0fd: lda yShipNew ; 3 sta yShip ; 3 ; stop ship: lda #0 ; 2 ldx #5 ; 2 .loopStop: sta speedLst,x ; 4 dex ; 2 bpl .loopStop ; 2³ lda game ; 3 and #TWO_PLAYERS ; 2 bne .twoPlayer ; 2³ sta lifesDir2 ; 3 no 2nd player, no lifes beq .endCollisionsJmp; 3 .twoPlayer: lda lifesDir2 ; 3 other player still alive? beq .endCollisionsJmp; 2³ no, skip swapping players lda flags2 ; 3 and #KILL_FLAG ; 2 ship killed? beq .endCollisionsJmp; 2³ no, skip swapping jsr SwapPlayers ; 6 lda #Y_ILLEGAL ; 2 disable first sta yPosLst ; 3 up and low moving sta yPosLst+NUM_ASTEROIDS_2; 3 asteroids lda #0 ; 2 sta lwrBound ; 3 lda #NUM_ASTEROIDS_2 ; 2 sta uprBound ; 3 .endCollisionsJmp: jmp .endCollisions ; 3 ; ******************** C O L L I S I O N S (start) ******************** .checkCollisions: lda asteroidHit ; 3 beq .cxObjects ; 2³ .cxAsteroids: ; check down moving asteroids: ldx lwrBound ; 3 stx $f5 ; 3 ldx #0 ; 2 jsr AsteroidHit ; 6 stx lwrBound ; 3 ; check up moving asteroids: ldx uprBound ; 3 stx $f5 ; 3 ldx #NUM_ASTEROIDS_2 ; 2 jsr AsteroidHit ; 6 stx uprBound ; 3 lda #0 ; 2 sta asteroidHit ; 3 no asteroid hit beq .endCollisionsJmp; 3 .cxObjects: ; every 2nd frame lda cxTimer ; 3 bit cxTimer ; 3 bpl .cxOther ; 2³ branch every 4th frame eor #$c0 ; 2 sta cxTimer ; 3 bvc .cxShot2 ; 2³ branch every 8th frame ; check for shot 1 with asteroids/UFO collisions: lda dirShot1 ; 3 shot enabled? beq .cxObjects ; 2³ no, try other objects lda yShot1 ; 3 ldy xShot1 ; 3 ldx #ID_SHOT1 ; 2 jsr CXAsteroids ; 6 ldy yUFO ; 3 cpy #Y_ILLEGAL ; 2 beq .skipUfo1 ; 2³ jsr CheckUFO ; 6 ldy xUFO ; 3 jsr Lfba9 ; 6 .skipUfo1: jmp .endCollisions ; 3 .cxShot2: ; check for shot 2 with asteroids/UFO collisions: lda dirShot2 ; 3 shot enabled? beq .cxObjects ; 2³ no, try other objects lda yShot2 ; 3 ldy xShot2 ; 3 ldx #ID_SHOT2 ; 2 jsr CXAsteroids ; 6 ldy yUFO ; 3 cpy #Y_ILLEGAL ; 2 beq .skipUfo2 ; 2³ jsr CheckUFO ; 6 ldy xUFO ; 3 jsr Lfba9 ; 6 .skipUfo2: jmp .endCollisions ; 3 .cxOther: ; every 4th frame and #$03 ; 2 a = cxTimer tax ; 2 inc cxTimer ; 5 lda cxTimer ; 3 ora #$80 ; 2 other branch next time tay ; 2 and #$03 ; 2 cmp #$03 ; 2 bne .reset3 ; 2³ tya ; 2 and #~$03 ; 2 tay ; 2 .reset3: sty cxTimer ; 3 dex ; 2 bmi .cxUFOShot ; 2³ check UFOShot dex ; 2 bmi .cxUFO ; 2³ check UFO bit flags2 ; 3 shield enabled? bvc cxShip ; 2³ no, check ship .cxObjectsJmp: jmp .cxObjects ; 3 yes, try player shots instead! cxShip: ; every 12 frame ; check for ship with asteroids/UFO collisions: lda ftrTimer ; 3 bmi .skipUfoShip ; 2³ ldy xShip ; 3 ldx #ID_SHIP ; 2 lda yShip ; 3 jsr CXAsteroids ; 6 ldy yUFO ; 3 cpy #Y_ILLEGAL ; 2 beq .skipUfoShip ; 2³ jsr CheckUFO ; 6 ldy xUFO ; 3 jsr Lfba9 ; 6 .skipUfoShip: jmp .endCollisions ; 3 .cxUFO: ; every 12 frame ; check for UFO with asteroids collisions: ldy yUFO ; 3 cpy #Y_ILLEGAL ; 2 UFO enabled? beq .cxObjectsJmp ; 2³ no, try player shots instead! jsr CheckUFO ; 6 ldy xUFO ; 3 jsr CXAsteroids ; 6 jmp .endCollisions ; 3 .cxUFOShot: ; every 12 frame ; check for UFO shot with asteroids/ship collisions: lda dirShotUfo ; 3 UFO shot enabled? beq .cxObjectsJmp ; 2³ no, try player shots instead! lda yShotUfo ; 3 ldy xShotUfo ; 3 ldx #ID_SHOT_UFO ; 2 jsr CXAsteroids ; 6 ldy yShip ; 3 cpy #Y_ILLEGAL ; 2 beq .endCollisions ; 2³+1 bit flags2 ; 3 shield enabled? bvs .endCollisions ; 2³ yes lda ftrTimer ; 3 bmi .endCollisions ; 2³ ldx #ID_SHIP ; 2 tya ; 2 ldy xShip ; 3 jsr Lfba9 ; 6 .endCollisions: ; ******************** C O L L I S I O N S (end) ******************** ; ******************** S O U N D (start) ******************** SUBROUTINE .tmpSound = $f4 lda flags2 ; 3 ror ; 2 game over? bcc .doSounds ; 2³ no, lda #$00 ; 2 sta AUDV0 ; 3 sta AUDV1 ; 3 jmp EndSound ; 3 .doSounds: lda soundBits ; 3 sta .tmpSound ; 3 ; set audio channel 0: ldy #$08 ; 2 ror .tmpSound ; 5 (bit 0) bcc Lf240 ; 2³ lda frameCnt ; 3 ror ; 2 bcs Lf238 ; 2³ dec soundTimer0 ; 5 bne Lf238 ; 2³ lda soundBits ; 3 and #~SOUND_KILL ; 2 sta soundBits ; 3 bcc Lf240 ; 3 Lf238: ror .tmpSound ; 5 thrust sound? ldx #$1f ; 2 lda soundTimer0 ; 3 bpl .setSound0 ; 3 Lf240: ; ror .tmpSound ; 5 thrust sound? (bit 1) bcc .noSound0 ; 2³ no ldx #$08 ; 2 lda #$06 ; 2 bpl .setSound0 ; 3 .noSound0: lda #$00 ; 2 .setSound0: sty AUDC0 ; 3 stx AUDF0 ; 3 sta AUDV0 ; 3 ; set audio channel 1: ror .tmpSound ; 5 (bit 2) bcc Lf274 ; 2³ ldx #$04 ; 2 ldy #$0f ; 2 lda soundTimer1 ; 3 and #$10 ; 2 beq Lf262 ; 2³ ldy #$00 ; 2 Lf262: tya ; 2 ldy #$04 ; 2 dec soundTimer1 ; 5 bne .setSound1 ; 2³ lda soundBits ; 3 and #$eb ; 2 sta soundBits ; 3 inc soundTimer1 ; 5 jmp Lf2a4 ; 3 Lf274: ror .tmpSound ; 5 UFO active? (bit 3) bcc Lf290 ; 2³ no, ldx #$08 ; 2 lda flags ; 3 and #UFO_FLAG ; 2 UFO sound? bne Lf282 ; 2³ yes ldx #$10 ; 2 no, Sattelite sound Lf282: lda frameCnt ; 3 and #$02 ; 2 beq Lf28a ; 2³ dex ; 2 dex ; 2 Lf28a: ldy #$0c ; 2 lda #$08 ; 2 bpl .setSound1 ; 3 Lf290: ror .tmpSound ; 5 (bit 4) bcc Lf2ca ; 2³ dec soundTimer1 ; 5 bne Lf2ab ; 2³ lda soundBits ; 3 and #~[SOUND_ENEMY] ; 2 ora #$60 ; 2 sta soundBits ; 3 lda #$08 ; 2 sta soundTimer1 ; 3 Lf2a4: lda #$00 ; 2 sta AUDV1 ; 3 jmp EndSound ; 3 Lf2ab: ldy #$0c ; 2 lda soundTimer1 ; 3 cmp #$08 ; 2 bcc Lf2ba ; 2³ lda frameCnt ; 3 ror ; 2 bcc Lf2ba ; 2³ ldy #$08 ; 2 Lf2ba: lda #$0f ; 2 sec ; 2 sbc soundTimer1 ; 3 tax ; 2 lda #$0d ; 2 .setSound1: sty AUDC1 ; 3 stx AUDF1 ; 3 sta AUDV1 ; 3 bpl EndSound ; 3+1 Lf2ca: ldy #$06 ; 2 dec soundTimer1 ; 5 bne Lf2f5 ; 2³ lda soundBits ; 3 and #$9f ; 2 ror .tmpSound ; 5 (bit 5) bcs Lf308 ; 2³+1 ora #$20 ; 2 ror .tmpSound ; 5 bcc Lf2e0 ; 2³ (bit 6) ora #$40 ; 2 Lf2e0: sta soundBits ; 3 lda frameCntHi ; 3 bmi Lf2f1 ; 2³ IF NTSC lda #14 ; 2 ELSE lda #12 ; 2 ENDIF sec ; 2 sbc frameCntHi ; 3 bmi Lf2f1 ; 2³ IF NTSC cmp #6 ; 2 ELSE cmp #4 ; 2 ENDIF bcs Lf2f3 ; 2³ Lf2f1: IF NTSC lda #6 ; 2 ELSE lda #4 ; 2 ENDIF Lf2f3: sta soundTimer1 ; 3 Lf2f5: lda soundBits ; 3 rol ; 2 rol ; 2 bmi Lf2ff ; 2³ lda #$00 ; 2 beq .setSound1 ; 3 Lf2ff: ldx #$13 ; 2 bcc Lf304 ; 2³ inx ; 2 Lf304: lda #$0c ; 2 bpl .setSound1 ; 3+1 Lf308: ror .tmpSound ; 5 (bit 7) bcs Lf30e ; 2³ ora #$40 ; 2 Lf30e: sta soundBits ; 3 IF NTSC lda #$08 ; 2 ELSE lda #$06 ; 2 ENDIF sta soundTimer1 ; 3 bpl Lf2f5 ; 2³+1 EndSound: ; ******************** S O U N D (end) ******************** ; ******************** V S Y N C (start) ******************** ldx #$ff ; 2 Lf318: lda INTIM ; 4 bne Lf318 ; 2³ stx VBLANK ; 3 stx VSYNC ; 3 sta WSYNC ; 3 sta WSYNC ; 3 sta WSYNC ; 3 sta VSYNC ; 3 sta VBLANK ; 3 ; ******************** V S Y N C (end) ******************** IF NTSC lda #$2d ; 2 ELSE lda #$35 ; 2 ENDIF sta TIM64T ; 4 inc frameCnt ; 5 bne .skipSwap ; 2³ inc frameCntHi ; 5 bit flags ; 3 select mode? bvs .skipSwap ; 2³ yes, lda flags2 ; 3 ror ; 2 game over? bcc .skipSwap ; 2³ yes, lda frameCntHi ; 3 bpl Lf349 ; 2³ lda flags ; 3 ora #SELECT_FLAG ; 2 sta flags ; 3 Lf349: lda game ; 3 and #TWO_PLAYERS ; 2 two player game? beq .skipSwap ; 2³ no jsr SwapPlayers ; 6 .skipSwap: jsr NextRandom ; 6 IF ORIGINAL lda frameCnt ; 3 ror ; 2 ELSE jsr CheckDriving ENDIF bcs .oddFrame ; 2³ jmp .evenFrame ; 3 ; ******************** A S T E R O I D S (start) ******************** .oddFrame: ; *** countdown timers *** ldy #0 ; 2 lda gameSpeed ; 3 sec ; 2 sbc #$11 ; 2 cmp #$10 ; 2 bcs .skipResetHi ; 2³ ora #SPEED_SLOW ; 2 $70..$00/$50..$00 iny ; 2 iny ; 2 .skipResetHi: tax ; 2 and #$0f ; 2 bne skipResetLo ; 2³ txa ; 2 ora #SPEED_MEDIUM ; 2 $03..$00/$02..$00 tax ; 2 iny ; 2 skipResetLo: stx gameSpeed ; 3 tya ; 2 a = 0..3 ror ; 2 ror ; 2 ror ; 2 sta moveBits ; 3 = $00, $40, $80, $c0 lda #HMSizeTbl ; 2 sta ptr4+1 ; 3 ; *** move up-moving asteroids *** ldx #NUM_ASTEROIDS_2 ; 2 .loopUpr: ; loop until illegal y-position: lda yPosLst,x ; 4 cmp #Y_ILLEGAL ; 2 beq .exitLoopUpr ; 2³ inc yPosLst,x ; 6 move asteroid up jsr XMoveAsteroids ; 6 move asteroid left or right inx ; 2 bne .loopUpr ; 2³ .exitLoopUpr: ldx uprBound ; 3 lda yPosLst,x ; 4 cmp #Y_ILLEGAL ; 2 beq .setupMove1 ; 2³+1 cmp #H_KERNEL ; 2 bcc .checkWrapYUpr ; 2³ lda #Y_ILLEGAL ; 2 sta yPosLst,x ; 4 dec uprBound ; 5 bne .exitLoopUpr ; 3 .checkWrapYUpr: ; check if asteroid reached upper screen border: lda flagLst,x ; 4 lsr ; 2 lsr ; 2 lsr ; 2 lsr ; 2 and #[SIZE_BITS>>4] ; 2 tay ; 2 y = asteroids size id lda yPosLst,x ; 4 cmp UprBoundTbl,y ; 4 at upper border? bne .skipInsert ; 2³ no, skip stx $f5 ; 3 yes, save id lda #NUM_ASTEROIDS_2 ; 2 set bound sta $f4 ; 3 jsr InsertIntoLst ; 6 insert into list lda yPosLst,y ; 4 sec ; 2 sbc #H_KERNEL ; 2 sta yPosLst,x ; 4 correct y-position .skipInsert: ldx #NUM_ASTEROIDS_2 ; 2 lda yPosLst,x ; 4 cmp #Y_ILLEGAL ; 2 beq .setupMove1 ; 2³+1 lda xPosLst,x ; 4 sta fineMove1 ; 3 lsr ; 2 and #$07 ; 2 sta coarseMove1 ; 3 store delay lda yPosLst,x ; 4 bpl .setupMove1 ; 2³+1 cmp #$ff ; 2 beq .setupMove1 ; 2³+1 lda xPosLst,x ; 4 ror ; 2 ldy #GetHMSizeTbl1 ; 2 sty bswVec+1 ; 3 ldy #>4] ; 2 tay ; 2 lda yPosLst ; 3 cmp LwrBoundTbl,y ; 4 beq Lf498 ; 2³ lda flagLst ; 3 and #TYPE_BITS ; 2 sec ; 2 sbc yPosLst ; 3 sec ; 2 sbc #$02 ; 2 sta ptr1 ; 3 sta ptr3 ; 3 ldy #>GetHMSizeTbl0 ; 2 sty bswVec+1 ; 3 ldy #Asteroids ; 2 sta ptr1+1 ; 3 sta ptr2+1 ; 3 lda #>HMSizeTbl ; 2 sta ptr3+1 ; 3 sta ptr4+1 ; 3 lda #>Ld000 ; 2 sta jmpVec1+1 ; 3 lda #>EndXPosP0 ; 2 sta jmpVec2+1 ; 3 lda #0 ; 2 sta lwrBound ; 3 lda #NUM_ASTEROIDS_2 ; 2 sta uprBound ; 3 jmp SetupScoreJmp ; 3 ; ******************** A S T E R O I D S (end) ******************** ; ******************** O B J E C T S (start) ******************** .evenFrame: ; *** set the ships colors: *** lda #SHIP1_COL ; 2 bit flags ; 3 player 2 bpl .player1 ; 2³ no, lda #SHIP2_COL ; 2 .player1: sta shipCol ; 3 sta ballCol ; 3 ldx #SATTELITE_COL ; 2 lda flags ; 3 and #UFO_FLAG ; 2 beq Lf5ed ; 2³ ldx #UFO_COL ; 2 Lf5ed: stx enemyCol ; 3 lda #$00 ; 2 sta ssColor ; 3 lda lifesDir ; 3 any player still alive? ora lifesDir2 ; 3 and #LIFES_MASK ; 2 bne CheckJoystick ; 2³+1 sta AUDV1 ; 3 lda flags2 ; 3 ror ; 2 game over? bcs .screensaver ; 2³ yes, ldx #$01 ; 2 stx frameCntHi ; 3 dex ; 2 stx frameCnt ; 3 lda flags2 ; 3 ora #GAME_OVER ; 2 sta flags2 ; 3 .screensaver: lda frameCntHi ; 3 rol ; 2 adc #$00 ; 2 rol ; 2 adc #$00 ; 2 rol ; 2 adc #$00 ; 2 rol ; 2 adc #$00 ; 2 and #$f7 ; 2 sta COLUBK ; 3 sta ssColor ; 3 jmp SetupKernel ; 3 CheckJoystick SUBROUTINE .joystick = $f3 lda SWCHA IF ORIGINAL bit flags ; 3 player 2 bpl .player1 ; 2³ no, asl ; 2 asl ; 2 asl ; 2 asl ; 2 .player1: and #$f0 sta .joystick ; 3 ELSE and #$f0 sta .joystick ; 3 -> joystick 1 bit $f3 bit $f3 bit $f3 bit $f3 ENDIF bit flags2 ; 3 shield enabled? bvc Lf669 ; 2³ no and #$20 ; 2 joystick down? beq .checkFeatures ; 2³ yes lda flags2 ; 3 and #~SHIELD_FLAG ; 2 sta flags2 ; 3 jmp Lf669 ; 3 .checkFeatures: inc ftrTimer ; 5 increase shield timer lda ftrTimer ; 3 and #$1f ; 2 shield time up? bne Lf666 ; 2³ no, lda flags2 ; 3 and #~SHIELD_FLAG ; 2 disable shield and... ora #KILL_FLAG ; 2 ...enable kill flag sta flags2 ; 3 lda #$80 ; 2 reset timer sta ftrTimer ; 3 lda soundBits ; 3 start explosion sound ora #SOUND_KILL ; 2 and #~SOUND_THRUST ; 2 sta soundBits ; 3 lda #$0f ; 2 sta soundTimer0 ; 3 Lf666: jmp .noThrust ; 3 Lf669: lda yShip ; 3 cmp #Y_ILLEGAL ; 2 ship visible`? beq Lf679 ; 2³ no, lda ftrTimer ; 3 timer? beq Lf682 ; 2³ clear, bmi Lf67f ; 2³ negative, dec ftrTimer ; 5 no, decrease bpl Lf682 ; 3 Lf679: lda ftrTimer ; 3 beq Lf67f ; 2³ dec ftrTimer ; 5 Lf67f: jmp SetupKernel ; 3 Lf682: lda .joystick ; 3 cmp #$d0 ; 2 only joystick down pressed? bne .notDown ; 2³ no lda game ; 3 which feature? and #FEATURE_BITS ; 2 Hyperspace beq .hyperspace ; 2³ yes! cmp #FEATURE_BITS ; 2 none? beq .notDown ; 2³ yes! and #$08 ; 2 Shield? bne .shield ; 2³ yes! bit flags2 ; 3 just flipped? (FLIP_FLAG) bmi .endFeatures ; 2³ yes, not again! ; Flip! lda lifesDir ; 3 eor #$08 ; 2 flip direction! sta lifesDir ; 3 lda flags2 ; 3 ora #FLIP_FLAG ; 2 sta flags2 ; 3 bne .endFeatures ; 3 .shield: lda flags2 ; 3 ora #SHIELD_FLAG ; 2 sta flags2 ; 3 inc ftrTimer ; 5 bne .endFeatures ; 3 .hyperspace: lda flags2 ; 3 and #HYPERSPACE_FLAG ; 2 bne .newShipPos ; 2³ lda flags2 ; 3 ora #HYPERSPACE_FLAG ; 2 sta flags2 ; 3 bne .endFeatures ; 3 .newShipPos: ; calculate new ship position: lda yShip ; 3 cmp #Y_ILLEGAL ; 2 already caclulated? beq .endFeatures ; 2³ yes, skip lda #Y_ILLEGAL ; 2 sta yShip ; 3 lda flags2 ; 3 and #~[KILL_FLAG|HYPERSPACE_FLAG]; 2 sta flags2 ; 3 jsr GetRandomX ; 6 sta xShip ; 3 lda randomLo ; 3 lsr ; 2 cmp #H_KERNEL-10 ; 2 bcc .yPosOk ; 2³ sbc #H_KERNEL-10 ; 2 .yPosOk: sta yShipNew ; 3 lda #0 ; 2 stop ship ldx #5 ; 2 .loopStop: sta speedLst,x ; 4 dex ; 2 bpl .loopStop ; 2³ lda #$1f ; 2 init timer sta ftrTimer ; 3 jmp SetupKernel ; 3 .notDown: ; disable all features: lda flags2 ; 3 and #~[FLIP_FLAG|SHIELD_FLAG|HYPERSPACE_FLAG] ; 2 sta flags2 ; 3 .endFeatures: ; *** turn ship: *** lda frameCnt ; 3 ror ; 2 ror ; 2 bcc .skipTurn ; 2³+1 lda lifesDir ; 3 and #LIFES_MASK ; 2 sta $f4 ; 3 asl .joystick ; 5 joystick right? bcs .skipRight ; 2³ no, skip dec lifesDir ; 5 yes, turn right .skipRight: asl .joystick ; 5 joystick left? bcs .skipLeft ; 2³ no, skip inc lifesDir ; 5 yes, turn left .skipLeft: lda lifesDir ; 3 and #DIR_MASK ; 2 ora $f4 ; 3 sta lifesDir ; 3 jmp .endTurn ; 3 .skipTurn: asl .joystick ; 5 superflous code now asl .joystick ; 5 .endTurn: asl .joystick ; 5 ; *** fire shots: *** ldy #1 ; 2 bit flags ; 3 player 2? bmi .player2 ; 2³ yes, ldy #0 ; 2 .player2: IF ORIGINAL lda INPT4,y ; 4 check fire button of current player ELSE lda INPT4 ; 4 check both buttons in hack and INPT5 ; 4 ENDIF bmi .noFire ; 2³ lda flags ; 3 and #FIRE_FLAG ; 2 fire button was up? bne .skipNewShot ; 2³ no lda flags ; 3 ora #FIRE_FLAG ; 2 mark fire button as down sta flags ; 3 ; new player shot possible? ldy #$01 ; 2 lda dirShot2 ; 3 beq .shot2 ; 2³ dey ; 2 lda dirShot1 ; 3 bne .skipNewShot ; 2³ .shot2: lda yShip ; 3 clc ; 2 adc #$03 ; 2 sta yShotLst,y ; 5 IF ORIGINAL lda xShip ; 3 sta xShotLst,y ; 5 ELSE ldx xShip ; 3 save two bytes stx xShotLst,y ; 5 ENDIF lda soundBits ; 3 and #$04 ; 2 bne .skipShotSound ; 2³ lda soundBits ; 3 start fireing sound ora #SOUND_ENEMY ; 2 sta soundBits ; 3 lda #15 ; 2 sta soundTimer1 ; 3 .skipShotSound: lda lifesDir ; 3 and #DIR_MASK/2 ; 2 tax ; 2 lda lifesDir ; 3 and #DIR_MASK ; 2 ora ShotRangeTbl,x ; 4 sta dirShotLst,y ; 5 jmp .skipNewShot ; 3 .noFire: lda flags ; 3 and #~FIRE_FLAG ; 2 sta flags ; 3 .skipNewShot: ; *** thrust: *** IF SADISTROIDS = 0 asl .joystick ; 5 thrust? bcs .noThrust ; 2³ no lda soundBits ; 3 ora #SOUND_THRUST ; 2 sta soundBits ; 3 lda lifesDir ; 3 and #DIR_MASK ; 2 tay ; 2 lda ThrustTbl,y ; 4 bpl Lf78e ; 2³ dec speedMidY ; 5 Lf78e: clc ; 2 adc speedLoY ; 3 sta speedLoY ; 3 bcc Lf797 ; 2³ inc speedMidY ; 5 Lf797: tya ; 2 clc ; 2 adc #$04 ; 2 and #$0f ; 2 tay ; 2 lda ThrustTbl,y ; 4 bpl Lf7a5 ; 2³ dec speedMidX ; 5 Lf7a5: clc ; 2 adc speedLoX ; 3 sta speedLoX ; 3 bcc Lf7ae ; 2³ inc speedMidX ; 5 Lf7ae: jmp .skipFriction ; 3 .noThrust: lda soundBits ; 3 and #~SOUND_THRUST ; 2 sta soundBits ; 3 ELSE ; double thrust! asl .joystick ; 5 thrust? lda soundBits ; 3 bcs .noThrust ; 2³ no ora #SOUND_THRUST ; 2 sta soundBits ; 3 lda lifesDir ; 3 ldx #1 ; 2 .loopThrust: and #DIR_MASK ; 2 tay ; 2 lda ThrustTbl,y ; 4 bpl Lf78e ; 2³ dec speedMidX,x ; 5 dec speedMidX,x ; 5 Lf78e: clc ; 2 adc speedLoX,x ; 3 bcc Lf797 ; 2³ inc speedMidX,x ; 5 Lf797: clc adc ThrustTbl,y ; 4 bcc Lf797a ; 2³ inc speedMidX,x ; 5 Lf797a: sta speedLoX,x ; 3 tya ; 2 clc ; 2 adc #$04 ; 2 dex ; 2 bpl .loopThrust ; 2³ bmi .skipFriction ; 3 ds 7, 0 .noThrust: and #~SOUND_THRUST ; 2 sta soundBits ; 3 ENDIF ; *** friction: *** ldx #1 ; 2 .loopFriction: lda speedMidLst,x ; 4 ship moving at this axis? ora speedLoLst,x ; 4 beq .nextAxis ; 2³ no, skip lda speedMidLst,x ; 4 more speed, more friction IF ORIGINAL asl ; 2 ELSE nop ; 2 less friction ENDIF ldy #$ff ; 2 clc ; 2 eor #$ff ; 2 friction works in opposite direction bmi .posSpeed ; 2³ iny ; 2 sec ; 2 .posSpeed: adc speedLoLst,x ; 4 sta speedLoLst,x ; 4 tya ; 2 adc speedMidLst,x ; 4 sta speedMidLst,x ; 4 .nextAxis: dex ; 2 bpl .loopFriction ; 2³ .skipFriction: ; *** move ship: *** ldx #1 ; 2 .loopMoveShip: lda speedMidLst,x ; 4 tay ; 2 rol ; 2 eor speedMidLst,x ; 4 rol ; 2 tya ; 2 bcc Lf7e7 ; 2³ bit 7 == bit 6 ! eor #$7f ; 2 sta speedMidLst,x ; 4 Lf7e7: ror ; 2 JTZ: how about using lsr instead? ror ; 2 ror ; 2 ror ; 2 and #$0f ; 2 cpy #0 ; 2 pos/neg speed? bpl Lf7f3 ; 2³ positive ora #$f0 ; 2 Lf7f3: sta $f4 ; 3 = speedMid high nibble tya ; 2 rol ; 2 JTZ: how about using asl instead? rol ; 2 rol ; 2 rol ; 2 and #$f0 ; 2 sta $f5 ; 3 lda speedLoLst,x ; 4 ror ; 2 JTZ: how about using lsr instead? ror ; 2 ror ; 2 ror ; 2 and #$0f ; 2 ora $f5 ; 3 $f5 = (MMMM)mmmmLLLL(llll) clc ; 2 adc speedHiLst,x ; 4 sta speedHiLst,x ; 4 lda $f4 ; 3 php ; 3 cpx #0 ; 2 looping for x-speed? beq .exitMoveShip ; 2³ yes, exit loop plp ; 4 adc yShip ; 3 sta yShip ; 3 dex ; 2 bpl .loopMoveShip ; 3+1 .exitMoveShip: plp ; 4 bmi Lf823 ; 2³ adc #$00 ; 2 bpl Lf825 ; 2³ Lf823: sbc #$00 ; 2 Lf825: sec ; 2 cmp #$00 ; 2 bpl Lf82d ; 2³ eor #$ff ; 2 clc ; 2 Lf82d: beq SetupKernel ; 2³ ldx #xShip-xPosLst ; 2 jsr XMoveObjJSR ; 6 -> move xShip ; *** setup kernel variables: *** SetupKernel: lda #>Ship ; 2 sta ptrShip+1 ; 3 sta ptrEnemy+1 ; 3 lda flags ; 3 and #COLLISION_FLAG ; 2 beq .noCollision ; 2³ lda # ptr at $dfc1 (=$ff) bpl .posDir ; 3 Lf8ad: bit flags2 ; 3 shield? bvc .noShield ; 2³ no, show ship lda #$00 ; 2 yes, sta $f4 ; 3 disable reflection... lda #ShowCopyright ; 2 sta bswVec+1 ; 3 jmp SwitchBank0 ; 3 ELSE bne StartMain ; 3 ENDIF StartNewGame: lda #COLLISION_FLAG ; 2 sta flags ; 3 StartMain: sta soundTimer1 ; 3 lda #$fe ; 2 sta ptr3+1 ; 3 sta ptr4+1 ; 3 lda #$ff ; 2 sta ptr1+1 ; 3 sta ptr2+1 ; 3 lda #>OverScan ; 2 sta jmpVec1+1 ; 3 lda #>Lf100 ; 2 sta jmpVec2+1 ; 3 jsr SetupAsteroids ; 6 lda #SPEED_SLOW|SPEED_MEDIUM; 2 sta gameSpeed ; 3 lda #>4] ; 2 slow! bpl .contSlow ; 3 .fastMode: lda $f5 ; 3 .contSlow: tay ; 2 lda XSpeedTbl,y ; 4 $00, $40, $80 beq DoXMove ; 2³ move always! .contChild: bit moveBits ; 3 bne DoXMove ; 2³ rts ; 6 .childMode: ; in childrens mode, all asteroids lda #$80 ; 2 are moving slowly bne .contChild ; 3 ;XMoveAsteroids DoXMove SUBROUTINE ; moves object one pixel left or right bcs .moveLeft ; 2³ ;*** move object right: *** lda #$f0 ; 2 adc xPosLst,x ; 4 cmp #$93 ; 2 bne Lfa70 ; 2³ lda #$65 ; 2 bne .ok ; 3 Lfa70: cmp #$70 ; 2 bcc .ok ; 2³ cmp #$80 ; 2 bcs .ok ; 2³ and #$0f ; 2 tay ; 2 lda RightWrapTbl,y ; 4 bne .ok ; 2³ ;*** move object left: *** .moveLeft: lda #$0f ; 2 adc xPosLst,x ; 4 +#$10 (C=1!) cmp #$42 ; 2 bne Lfa8c ; 2³ lda #$8d ; 2 bne .ok ; 3 Lfa8c: cmp #$70 ; 2 bcc .ok ; 2³ cmp #$80 ; 2 bcs .ok ; 2³ and #$0f ; 2 tay ; 2 lda LeftWrapTbl,y ; 4 .ok: sta xPosLst,x ; 4 rts ; 6 GetRandomX SUBROUTINE lda randomHi ; 3 and #$07 ; 2 tay ; 2 lda randomHi ; 3 and #$f0 ; 2 cmp #$70 ; 2 $70 <= a < $80? bcc Lfab0 ; 2³ cmp #$80 ; 2 bcs Lfab0 ; 2³ lda #$80 ; 2 ja, -> a = $80 Lfab0: ora RandomXTbl,y ; 4 cmp #$42 ; 2 useless code!!! bne Lfac1 ; 2³ " cmp #$52 ; 2 " bne Lfac1 ; 2³ " cmp #$62 ; 2 " bne Lfac1 ; 2³ " lda #$8d ; 2 " Lfac1: rts ; 6 XMoveObjJSR SUBROUTINE ldy #>XMoveObj ; 2 sty bswVec+1 ; 3 ldy #>4] ; 2 sta tmpVar ; 3 tya ; 2 clc ; 2 adc #3 ; 2 ldy xPosLst,x ; 4 stx .objIdHit ; 3 ldx tmpVar ; 3 jsr Lfba9 ; 6 bcs Lfb3c ; 2³ ldx .objIdHit ; 3 .nextAsteroid: inx ; 2 bne Lfb05 ; 3 Lfb3c: lda yPosLst ; 3 bpl Lfb52 ; 2³ ldx lwrBound ; 3 lda flagLst ; 3 ora flagLst,x ; 4 and #HIT_FLAG ; 2 Asteroid hit? beq Lfb52 ; 2³ no lda flagLst ; 3 ora #[HIT_FLAG|$4] ; 2 sta flagLst ; 3 sta flagLst,x ; 4 Lfb52: rts ; 6 Lfb53: ldx #NUM_ASTEROIDS_2 ; 2 Lfb55: lda yPosLst,x ; 4 cmp #Y_ILLEGAL ; 2 beq Lfb8c ; 2³ tay ; 2 clc ; 2 adc #17 ; 2 bmi Lfb6b ; 2³ cmp .top ; 3 bcs Lfb89 ; 2³ adc #15 ; 2 cmp .bottom ; 3 bcc Lfb89 ; 2³ Lfb6b: lda flagLst,x ; 4 rol ; 2 rol ; 2 Asteroid already hit? bcs Lfb89 ; 2³ yes rol ; 2 rol ; 2 rol ; 2 and #[TYPE_BITS>>4] ; 2 sta tmpVar ; 3 tya ; 2 clc ; 2 adc #3 ; 2 ldy xPosLst,x ; 4 stx .objIdHit ; 3 ldx tmpVar ; 3 jsr Lfba9 ; 6 bcs Lfb8c ; 2³ ldx .objIdHit ; 3 Lfb89: inx ; 2 bne Lfb55 ; 3 Lfb8c: ldy #NUM_ASTEROIDS_2 ; 2 lda yPosLst,y ; 4 bpl Lfba8 ; 2³ ldx uprBound ; 3 lda flagLst,x ; 4 ora flagLst,y ; 4 and #HIT_FLAG ; 2 beq Lfba8 ; 2³ lda flagLst,y ; 4 ora #[HIT_FLAG|$4] ; 2 sta flagLst,x ; 4 sta flagLst,y ; 5 Lfba8: rts ; 6 Lfba9: ; y = xPos ; a = yPos ; x = ID stx .objId2 ; 3 sty .xPos2 ; 3 clc ; 2 adc #17 ; 2 sta .tmpXPos ; 3 cmp .bottom ; 3 bcc .checkBelow ; 2³ lda .bottom ; 3 ldx .objId1 ; 3 adc YSizeTbl,x ; 4 sec ; 2 sbc .tmpXPos ; 3 bcs .checkX ; 2³ .noCollision: rts ; 6 .checkBelow: clc ; 2 adc YSizeTbl,x ; 4 sec ; 2 sbc .bottom ; 3 bcc .noCollision ; 2³ .checkX: lda .xPos2 ; 3 jsr Convert2X ; 6 sta .xPos2 ; 3 ldx .objId2 ; 3 cmp .xPos1 ; 3 bcc .checkLeft ; 2³ lda .xPos1 ; 3 ldx .objId1 ; 3 adc XSizeTbl,x ; 4 sec ; 2 sbc .xPos2 ; 3 bcs .collision ; 2³ rts ; 6 .checkLeft: clc ; 2 adc XSizeTbl,x ; 4 sec ; 2 sbc .xPos1 ; 3 bcc .noCollision ; 2³ .collision: ldx .objId1 ; 3 cpx #NUM_ASTEROIDS_2+1;2 bne Lfbf8 ; 2³ jmp .breakLoop ; 3 Lfbf8: cpx #ID_UFO ; 2 beq Lfc0a ; 2³+1 cpx #ID_SATTELITE ; 2 beq Lfc0a ; 2³+1 ldy .objId2 ; 3 cpy #ID_UFO ; 2 beq Lfc0a ; 2³ cpy #ID_SATTELITE ; 2 bne Lfc1b ; 2³ Lfc0a: lda flags ; 3 and #COLLISION_FLAG ; 2 beq Lfc11 ; 2³ .noKill: rts ; 6 Lfc11: lda flags ; 3 ora #COLLISION_FLAG ; 2 sta flags ; 3 lda #0 ; 2 sta ofsExpl ; 3 Lfc1b: cpx #ID_SHIP ; 2 beq .checkKill ; 2³ cpx #NUM_ASTEROIDS_2 ; 2 bne .killObject ; 2³ lda .objId2 ; 3 cmp #ID_SHIP ; 2 bne .killObject ; 2³ .checkKill: lda ftrTimer ; 3 timer negative? bmi .noKill ; 2³ yes lda flags2 ; 3 no, enable kill flag... ora #KILL_FLAG ; 2 sta flags2 ; 3 lda #$80 ; 2 ...and make timer negative sta ftrTimer ; 3 .killObject: lda soundBits ; 3 ora #SOUND_KILL ; 2 and #~SOUND_THRUST ; 2 sta soundBits ; 3 lda #15 ; 2 sta soundTimer0 ; 3 ldy .objId2 ; 3 cpy #ID_SHIP ; 2 asteroid? bcs .noAsteroid ; 2³ no, skip ldy .objIdHit ; 3 lda flagLst,y ; 4 ora #[HIT_FLAG|$4] ; 2 sta flagLst,y ; 5 mark asteroid as hit sta asteroidHit ; 3 and remember to check in next frame .noAsteroid: cpx #ID_SHOT1 ; 2 shot collision? bpl Lfc61 ; 2³ no ldy .objId2 ; 3 cpy #ID_SHOT_UFO ; 2 collided with UFO-shot? bne Lfc65 ; 2³ ldx #ID_SHOT_UFO ; 2 yes, hack Lfc61: lda #$00 ; 2 sta xShotLst-1,x ; 4 Lfc65: ; who collided? cpx #ID_SHOT_UFO ; 2 beq .noBonus ; 2³ cpx #ID_UFO ; 2 beq .noBonus ; 2³ cpx #ID_SATTELITE ; 2 beq .noBonus ; 2³ ldy .objId2 ; 3 clc ; 2 sed ; 2 lda scoreLow ; 3 adc ScoreLoTbl,y ; 4 sta scoreLow ; 3 lda ScoreHiTbl,y ; 4 bcs .checkBonus ; 2³ beq .noBonus ; 2³ .checkBonus: adc scoreHigh ; 3 sta scoreHigh ; 3 cld ; 2 tay ; 2 lda game ; 3 and #BONUS_BITS ; 2 beq .bonus5k ; 2³ cmp #BONUS_BITS ; 2 beq .noBonus ; 2³ ror ; 2 ror ; 2 tya ; 2 and #$1f ; 2 20,000? bcc .bonus20k ; 2³ yes and #$0f ; 2 10,000? .bonus20k: bne .noBonus ; 2³ no beq .incLifes ; 3 yes .bonus5k: tya ; 2 and #$0f ; 2 10,000? beq .incLifes ; 2³ yes cmp #$05 ; 2 5,000? bne .noBonus ; 2³ no .incLifes: lda lifesDir ; 3 clc ; 2 adc #$10 ; 2 tay ; 2 and #LIFES_MASK ; 2 cmp #$a0 ; 2 max lifes? beq .noBonus ; 2³ yes, skip bonus sty lifesDir ; 3 lda soundBits ; 3 ora #$04 ; 2 sta soundBits ; 3 lda #$7f ; 2 sta soundTimer1 ; 3 .noBonus: cld ; 2 sec ; 2 rts ; 6 .breakLoop: stx asteroidHit ; 3 remember to check asteroids in next frame pla ; 4 pla ; 4 sec ; 2 rts ; 6 ;CXAsteroids Convert2X SUBROUTINE ; converts HMOVE/Delay into x-Pos tax ; 2 and #$0f ; 2 tay ; 2 txa ; 2 lsr ; 2 lsr ; 2 lsr ; 2 lsr ; 2 tax ; 2 lda ConvertLoTbl,x ; 4 clc ; 2 adc ConvertHiTbl,y ; 4 rts ; 6 CheckUFO SUBROUTINE ldx #ID_SATTELITE ; 2 lda flags ; 3 and #UFO_FLAG ; 2 beq .sattelite ; 2³ dex ; 2 x = ID_UFO .sattelite: tya ; 2 rts ; 6 AsteroidHit SUBROUTINE ; check all asteroids in list for being hit .btmId = $f4 .bound = $f5 .tmpId = $f6 .tmpVar = $f7 stx .btmId ; 3 ; loop until inactive asteroid is found: .loop: lda yPosLst,x ; 4 bpl .active ; 2³ cmp #Y_ILLEGAL ; 2 loop until empty slot found bne .active ; 2³ ldx .bound ; 3 rts ; 6 .active: lda flagLst,x ; 4 tay ; 2 and #HIT_FLAG ; 2 Asteroid marked as hit? bne .isHit ; 2³+1 yes, destroy .contLoop: inx ; 2 bpl .loop ; 3 .kill: stx .tmpId ; 3 save current id jsr RemoveFromLst ; 6 remove object from list dec .bound ; 5 ldx .tmpId ; 3 restore current id bpl .loop ; 3+1 branch is always taken! .isHit: lda yPosLst,x ; 4 bmi .kill ; 2³+1 tya ; 2 and #SIZE_BITS ; 2 medium or small beq .large2Medium ; 2³ no, cmp #MEDIUM_SIZE ; 2 medium? bne .checkSmall ; 2³ no jmp Medium2Small ; 3 .checkSmall: cmp #SMALL_SIZE ; 2 a small one? beq .kill ; 3+1 yes .large2Medium: jsr NextRandom ; 6 and #[FAST_SPEED|$f] ; 2 ora #MEDIUM_SIZE ; 2 make it medium size sta flagLst,x ; 4 lda yPosLst,x ; 4 cmp #H_KERNEL-6 ; 2 asteroid near upper border? bcc .skipInsert ; 2³ no, skip jsr InsertIntoLst ; 6 yes, insert into list... lda yPosLst,y ; 4 sec ; 2 sbc #H_KERNEL ; 2 sta yPosLst,x ; 4 ...and move new asteroid down inc .bound ; 5 .skipInsert: bit game ; 3 children mode? bmi .contLoop ; 2³+1 yes, skip second asteroid jsr CheckMem ; 6 memory for 2nd asteroid? bcs .contLoop ; 2³+1 no, skip second asteroid lda yPosLst,x ; 4 asteroid near upper border? bmi .medAsteroid ; 2³ no cmp #H_KERNEL-10 ; 2 bcc .medAsteroid ; 2³ no ; the old asteroid was near the upper border: jsr InsertIntoLst ; 6 yes, insert into list lda flagLst,x ; 4 and #$08 ; 2 save direction of other asteroid sta .tmpVar ; 3 jsr NextRandom ; 6 and #[FAST_SPEED|$7] ; 2 ora #MEDIUM_SIZE ; 2 make it medium size ora .tmpVar ; 3 eor #$08 ; 2 use opposite direction here sta flagLst,x ; 4 lda xPosLst,y ; 4 copy x-position and... sta xPosLst,x ; 4 lda yPosLst,y ; 4 ...space new y-position by 10 pixel clc ; 2 adc #10 ; 2 sec ; 2 sbc #H_KERNEL ; 2 sta yPosLst,x ; 4 inc .bound ; 5 increase boundary jmp .contLoop ; 3 .medAsteroid: lda .btmId ; 3 save bottom id (0,9) sta .tmpVar ; 3 stx .btmId ; 3 and replace with current id ldx .bound ; 3 jsr MoveUpLst ; 6 make space for new asteroid ldx .btmId ; 3 increase current id inx ; 2 lda .tmpVar ; 3 restore bottom id sta .btmId ; 3 inc .bound ; 5 increase boundary lda flagLst,x ; 4 save x-direction and #$08 ; 2 sta .tmpVar ; 3 jsr NextRandom ; 6 create new asteroid and #[FAST_SPEED|$7] ; 2 ora #MEDIUM_SIZE ; 2 make it medium size ora .tmpVar ; 3 eor #$08 ; 2 use opposite x-direction here sta flagLst,x ; 4 lda xPosLst-1,x ; 4 copy x-position and... sta xPosLst,x ; 4 lda yPosLst-1,x ; 4 ...space new y-position by 10 pixel clc ; 2 adc #10 ; 2 cmp #H_KERNEL ; 2 sta yPosLst,x ; 4 bcs .insert ; 2³ cmp #H_KERNEL-6 ; 2 bcs .insert ; 2³ jmp .contLoop ; 3 .insert: jsr InsertIntoLst ; 6 lda yPosLst,y ; 4 sec ; 2 sbc #H_KERNEL ; 2 sta yPosLst,x ; 4 inc .bound ; 5 increase boundary jmp .contLoop ; 3 Medium2Small: jsr NextRandom ; 6 and #[FAST_SPEED|$f] ; 2 ora #SMALL_SIZE ; 2 make it small sta flagLst,x ; 4 lda yPosLst,x ; 4 cmp #H_KERNEL-3 ; 2 bcc .contLoopJmp ; 2³ jsr InsertIntoLst ; 6 lda yPosLst,y ; 4 sec ; 2 sbc #H_KERNEL ; 2 sta yPosLst,x ; 4 inc .bound ; 5 increase boundary .contLoopJmp: jmp .contLoop ; 3 ;AsteroidHit RemoveFromLst SUBROUTINE ; moves asteroid-data down one slot lda xPosLst+1,x ; 4 sta xPosLst,x ; 4 lda flagLst+1,x ; 4 sta flagLst,x ; 4 lda yPosLst+1,x ; 4 sta yPosLst,x ; 4 inx ; 2 cmp #Y_ILLEGAL ; 2 bne RemoveFromLst ; 2³ rts ; 6 SetupAsteroids SUBROUTINE ; creates 4..8 asteroids for new level .numAsteroids = $f4 ; determine number of asteroids: lda #$00 ; 2 $c0 bit game ; 3 child mode? bmi .setNum ; 2³+1 yes, make 2 asteroids ldx scoreHigh ; 3 < 1,000? beq .setNum ; 2³+1 yes, make 2 asteroids ora #$40 ; 2 cpx #$15 ; 2 <15,000? bcc .setNum ; 2³ yes, make 3 asteroids ora #$80 ; 2 no, make 4 asteroids .setNum: sta .numAsteroids ; 3 ldx #0 ; 2 jsr .make2_4 ; 6 stx lwrBound ; 3 ldx #NUM_ASTEROIDS_2 ; 2 jsr .make2_4 ; 6 stx uprBound ; 3 rts ; 6 .make2_4: ; this subroutine creates 2..4 asteroids lda #1 ; 2 sta yPosLst,x ; 4 jsr GetRandomX ; 6 sta xPosLst,x ; 4 jsr NextRandom ; 6 and #$1f ; 2 make large asteroid sta flagLst,x ; 4 inx ; 2 bit .numAsteroids ; 3 how many asteroids? bvc .make1 ; 2³ only one more bmi .make3 ; 2³ three more! lda #21 ; 2 cpx #NUM_ASTEROIDS_2 ; 2 bcs .make2Low ; 2³ bcc .make2High ; 3 .make3: lda #21 ; 2 sta yPosLst,x ; 4 jsr NextRandom ; 6 and #$e0 ; 2 ora #$0a ; 2 sta xPosLst,x ; 4 jsr NextRandom ; 6 and #$1f ; 2 make large asteroid sta flagLst,x ; 4 inx ; 2 .make2High: lda #42 ; 2 .make2Low: sta yPosLst,x ; 4 jsr NextRandom ; 6 and #$e0 ; 2 ora #$0a ; 2 sta xPosLst,x ; 4 jsr NextRandom ; 6 and #$1f ; 2 make large asteroid sta flagLst,x ; 4 inx ; 2 .make1: lda #63 ; 2 sta yPosLst,x ; 4 jsr GetRandomX ; 6 sta xPosLst,x ; 4 jsr NextRandom ; 6 and #$1f ; 2 make large asteroid sta flagLst,x ; 4 lda #Y_ILLEGAL ; 2 sta yPosLst+1,x ; 4 rts ; 6 ;SetupAsteroids InsertIntoLst SUBROUTINE ; ; inserts new asteroid into list .start = $f5 .moveId = $f6 stx .moveId ; 3 ldx .start ; 3 jsr MoveUpLst ; 6 ; fill now empty slot with new data: ldy .moveId ; 3 iny ; 2 lda xPosLst,y ; 4 sta xPosLst,x ; 4 lda flagLst,y ; 4 sta flagLst,x ; 4 rts ; 6 MoveUpLst SUBROUTINE ; moves asteroid-data up one slot .bound = $f4 inx ; 2 .loop: lda yPosLst,x ; 4 sta yPosLst+1,x ; 4 lda xPosLst,x ; 4 sta xPosLst+1,x ; 4 lda flagLst,x ; 4 sta flagLst+1,x ; 4 dex ; 2 cpx .bound ; 3 bpl .loop ; 2³ inx ; 2 rts ; 6 CheckMem SUBROUTINE lda $f5 ; 3 cmp #NUM_ASTEROIDS_2 ; 2 lwr/upr asteroid? bcs .checkUpr ; 2³ upr! cmp #6 ; 2 rts ; 6 .checkUpr: cmp #NUM_ASTEROIDS_2+6;2 rts ; 6 CheckSpace SUBROUTINE ; safe space around ship's starting position? lda yPosLst,x ; 4 tay ; 2 cmp #Y_ILLEGAL ; 2 bne .active ; 2³ rts ; 6 all ok, Z flag set .active: ; asteroid at horizontal center? lda xPosLst,x ; 4 and #$0f ; 2 cmp #13 ; 2 center column beq .checkCenter ; 2³ cmp #11 ; 2 left of center column beq .checkLR ; 2³ cmp #2 ; 2 right of center column beq .checkLR ; 2³ .contLoop: inx ; 2 bpl CheckSpace ; 2³ ; The marked four absolute values where forgotten to adjust when converting the ; copyrighted version to PAL. This caused the safe zone to become asymmetric ; in the copyrighted PAL version. ; The values on the right are from the original PAL release. .checkCenter: tya ; 2 bmi .contLoop ; 2³ cmp #8 ; 2 15 *!* bcc .contLoop ; 2³ cmp #64 ; 2 71 *!* bcs .contLoop ; 2³ cmp #0 ; 2 no safe space, Z flag cleared rts ; 6 .checkLR: tya ; 2 cmp #24 ; 2 31 *!* bcc .contLoop ; 2³ cmp #56 ; 2 63 *!* bcs .contLoop ; 2³ cmp #0 ; 2 no safe space, Z flag cleared rts ; 6 ShotRangeTbl: ; up, up/left, left, left/down .byte $60, $70, $70, $b0, $90, $b0, $70, $70 XSpeedTbl: ; $80 = slow (1/7), $40 = med (1/3), $00 = fast (1) IF ORIGINAL .byte $80 ; large 1/7 .byte $80 ; large 1/7 .byte $80 ; medium 1/7 .byte $80 ; small 1/7 .byte $80 ; ??? .byte $80 ; ??? .byte $80 ; ??? .byte $40 ; ??? .byte $80 ; ??? .byte $80 ; ??? .byte $40 ; medium 1/3 .byte $00 ; small 1/1 .byte $80 ; ??? .byte $80 ; ??? ELSE .byte $40 ; large 1/3 .byte $80 ; large 1/7 .byte $40 ; medium 1/3 .byte $40 ; small 1/3 .byte $80 ; ??? .byte $80 ; ??? .byte $80 ; ??? .byte $40 ; ??? ___ .byte $80 ; ??? .byte $80 ; ??? .byte $00 ; medium 1/1 .byte $00 ; small 1/1 .byte $80 ; ??? .byte $80 ; ??? ENDIF RightWrapTbl: .byte $40, $00, $64, $00, $66, $67, $68, $69 .byte $6a, $6b, $63 LeftWrapTbl: .byte $6d, $00, $32, $8a, $82, $a3, $84, $85 .byte $86, $87, $88, $89, $00, $8b RandomXTbl: .byte 6, 4, 5, 6, 7, 9, 7, 5 ; tables used to convert hmove/delay into x-pos: ConvertLoTbl: .byte $06, $05, $04, $03, $02, $01, $00, $00 .byte $0e, $0d, $0c, $0b, $0a, $09, $08, $07 ConvertHiTbl: ; stored interleaved! .byte $00, $00 .byte $55, $00 .byte $64, $0d .byte $73, $1c .byte $82, $2b .byte $91, $3a .byte $00, $49 YSizeTbl: .byte 14 ; large asteroid #1 .byte 14 ; large asteroid #2 .byte 6 ; medium asteroid .byte 3 ; small asteroid .byte 4 ; Ship .byte 4 ; UFO .byte 6 ; Sattelite .byte 2 ; Missile .byte 2 ; Missile .byte 2 ; Missile .byte 36 ; ??? XSizeTbl: .byte 15 ; large asteroid #1 .byte 15 ; large asteroid #2 .byte 7 ; medium asteroid .byte 3 ; small asteroid .byte 4 ; Ship .byte 4 ; UFO .byte 6 ; Sattelite .byte 2 ; Missile .byte 2 ; Missile .byte 2 ; Missile .byte 36 ; ??? ScoreLoTbl: .byte $02 ; + 20 Large Asteroid .byte $02 ; + 20 " " .byte $05 ; + 50 Medium " .byte $10 ; +100 Small " .byte $00 .byte $00 .byte $20 ; +200 Sattelite ScoreHiTbl: .byte $00 .byte $00 .byte $00 .byte $00 .byte $00 .byte $01 ; +1000 UFO .byte $00 LwrBoundTbl: ; boundaries for asteroids .byte -15 .byte -15 .byte -7 .byte -4 UprBoundTbl: .byte H_KERNEL-14 .byte H_KERNEL-14 .byte H_KERNEL-6 .byte H_KERNEL-3 ; tables for adjusting game number: AdjustFromTbl: .byte $60, $c1, $80, $e1 AdjustToTbl: .byte $c0, $60, $e0, $40 ThrustTbl: .byte -127,-117, -90, -49, 0, 49, 90, 117 .byte 127, 117, 90, 49, 0, -49, -90,-117 YShotTbl: .byte -4, -3, -3, -1, 0, 1, 3, 3 .byte 4, 3, 3, 1, 0, -1, -3, -3 XShotTbl: .byte 0, 1, 3, 3, 4, 3, 3, 1 .byte 0, -1, -3, -3, -4, -3, -3, -1 SetupScoreJmp: lda #SetupScore ; 2 sta bswVec+1 ; 3 jmp SwitchBank0 ; 3 ;--------------------------------------------------------------- IF ORIGINAL = 0 CheckDriving SUBROUTINE lda lifesDir ; 3 and #LIFES_MASK ; 2 sta $f4 ; 3 lda lastDir and #%11100111 tay eor lastDir sty lastDir lsr lsr lsr tay lda SWCHA and #%11 asl asl asl ora lastDir sta lastDir lda SWCHA and #%11 eor NextLeftTab,y ; works like cmp for beq beq .leftTurn eor #%11 beq .rightTurn ;TODO: check for double turn bne .noTurn .leftTurn: inc lifesDir ; 5 .byte $2c ;-1 BIT_W .rightTurn: dec lifesDir ; 5 .noTurn: lda lifesDir ; 3 and #DIR_MASK ; 2 ora $f4 ; 3 sta lifesDir ; 3 ; and finally the original code: lda frameCnt ; 3 ror ; 2 rts NextLeftTab: .byte %01 .byte %11 .byte %00 .byte %10 ENDIF ORG $eff0, 0 RORG $fff0 SwitchBank0: sta BANK0 ; 4 jmp (bswVec) ; 5 IF NTSC .byte $00, $00, $44, $00 ELSE .byte $00, $00, $ff, $00 ENDIF .word START1, START1, START1