; Level 1 ;; GAME PARAMETERS NUM_MISSILES = 2 NUM_ENEMIES = 6 UP_SHIELDS = 32 WAVE_SIZE = 16 WAVES_TILL_BOSS = 5 ;; BONUS_FLAGS PERFECT_SHIELDS = $80 PERFECT_KILLS = $40 PERFECT_AIM = $1 ; Page zero locations shipx = $02 star_scroll = $03 star_scroll_h = $04 ; 0004 too, 16-bit RANDOM_SEED = $05 YSAV = $06 YSAV_H = $07 joypad1_raw = $08 joypad1_raw_h = $09 joypad1_pressed = $0a joypad1_pressed_h = $0b joypad1_held = $0c joypad1_held_h = $0d sprite_l = $10 sprite_h = $11 SPRITE_HIGH_LOOKUP = $20 SHL2 = $21 SHL3 = $22 SHL4 = $23 HISCORE_1 = $cb HISCORE_2 = $cc HISCORE_3 = $cd HISCORE_H = $ce HISCORE_L = $cf BOSS_X = $d0 BOSS_XADD = $d1 BOSS_COUNT = $d2 BOSS_SMOKE = $d3 BOSS_EXPLODING = $d4 BOSS_WAITING = $d5 BOSS_HITS = $d6 BOSS_SHOOTING = $d7 ENEMIES_SPAWNED = $d8 ENEMY_TYPE = $d9 ENEMY_WAVE = $da CURRENT_INIT_X = $db CURRENT_ENEMY_KIND = $dc TOTAL_ENEMIES_OUT = $dd SCROLL = $de SOUND_ON = $df SHIPXADD = $e1 ENEMY_PL = $e2 ENEMY_PH = $e3 MISSILE_PL = $e4 MISSILE_PH = $e5 GR_PAGE = $e6 LEVEL = $e7 SHIELDS = $e8 SCOREL = $e9 SCOREH = $ea BONUS_FLAGS = $eb BCD_BYTEH = $ec BCD_BYTE = $ed COL_X1 = $ec COL_X2 = $ed COL_X3 = $ee COL_X4 = $ef ENEMY_EXPLODING = $f0 ENEMY_KIND = $f1 ENEMY_X = $f2 ENEMY_Y = $f3 ENEMY_XADD = $f4 ENEMY_YADD = $f5 ENEMY_XMIN = $f6 ENEMY_XMAX = $f7 BETWEEN_DELAY = $f8 ENEMY_WAIT = $f9 STRINGL = $fa STRINGH = $fb PARAM2 = $fc RESULT = $fd LASTKEY = $fe TEMP = $ff .setcpu "65816" .segment "STARTUP" ;================================================ ; LEVEL 1 ;================================================ level_1: sep #$20 ; mem/A = 8 bit .a8 rep #$10 ; X/Y = 16 bit .i16 ;========================== ; Setup Background ;========================== ; we want the BG1 Tilemap to start at VRAM $f000 ; Format is ; aaaa aass a is shifted by 10 for address ; ss = size of screen in tiles 00 = 32x32 ; ; 0111 1000 lda #$78 ; BG1 Tilemap starts at VRAM $f000/2 sta $2107 ; bg1 src ; we want the BG2 Tilemap to start at VRAM $d000 ; Format is ; aaaa aass a is shifted by 10 for address ; ss = size of screen in tiles 10 = 32x64 ; ; 0110 1010 lda #$6a ; BG2 Tilemap starts at VRAM $d000/2 sta $2108 ; bg2 src ; aaaa bbbb a= BG2 tiles, b= BG1 tiles ; bbbb<<13 ; 0000 0000 ; our BG1 tiles are stored starting in VRAM $0000 lda #$32 ; bg2 tile data starts at VRAM 5000/2 sta $210b ; bg1 tile data starts at VRAM 4000/2 ;=============================== ; Load Level1 Background Palette ;=============================== stz $2121 ; start with color 0 ldy #(16*2) ; we have 16 colors lda #^level1_background_palette ldx #.LOWORD(level1_background_palette) jsr svmw_load_palette ;====================== ; Load Level1 Tile Data ;====================== ldx #$2000 ; stx $2116 ; set adddress for VRAM read/write ; multiply by 2, so 0x4000 lda #^level1_background_tile_data ldx #.LOWORD(level1_background_tile_data) ldy #1824 ; Copy 57 tiles, which are 32 bytes each ; 8x8 tile with 4bpp ; (57*32) = 1824 = ???? jsr svmw_load_vram ;=================================== ; Load Level1 Tile Map ;=================================== ldx #$7800 ; stx $2116 ; set adddress for VRAM read/write ; multiply by 2, so 0xe000 lda #^level1_background_tilemap ldx #.LOWORD(level1_background_tilemap) ldy #$0700 ; 32x28 = 896 * 2 = 0x700 jsr svmw_load_vram ;=============================== ; Load Level1 Star Palette ;=============================== lda #16 sta $2121 ; start with color 16 ldy #(16*2) ; we have 16 colors lda #^star_background_palette ldx #.LOWORD(star_background_palette) jsr svmw_load_palette ;====================== ; Load Level1 Star Data ;====================== ldx #$3000 ; stx $2116 ; set adddress for VRAM read/write ; multiply by 2, so 0x4000 lda #^star_background_tile_data ldx #.LOWORD(star_background_tile_data) ldy #$4420 ; Copy 545 tiles, which are 32 bytes each ; 8x8 tile with 4bpp ; (545*32) = 17,440 = 0x4420 jsr svmw_load_vram ;=================================== ; Load Level1 Star Tile Map ;=================================== ldx #$6800 ; stx $2116 ; set adddress for VRAM read/write ; multiply by 2, so 0xd000 lda #^star_background_tilemap ldx #.LOWORD(star_background_tilemap) ldy #$1000 ; 32x64 = 2048 * 2 = 0x1000 jsr svmw_load_vram ;========================== ; Setup Sprites ;========================== ; Load Palette for our sprite ; Sprite Palettes start at color 128 ; Load palette 0 lda #128 ; start with color 128 sta $2121 ; ldy #(16*2) ; we have 16 colors lda #^level1_pal0_palette ldx #.LOWORD(level1_pal0_palette) jsr svmw_load_palette ; Load palette 2 lda #160 ; start with color 128 sta $2121 ; ldy #(16*2) ; we have 16 colors lda #^level1_pal2_palette ldx #.LOWORD(level1_pal2_palette) jsr svmw_load_palette ;========================= ; Load sprite data to VRAM ;========================= lda #$80 ; increment after writing $2119 sta $2115 ; Pal0 Sprites ldx #$0000 ; stx $2116 ; set adddress for VRAM read/write ; multiply by 2, so 0x0000 lda #^level1_pal0_data ldx #.LOWORD(level1_pal0_data) ldy #$0800 ; 32 bytes * 64 tiles jsr svmw_load_vram ; Pal2 Sprites ; 0x0000 + 32*0x60 / 2 = 0x600 ldx #$0600 ; stx $2116 ; set adddress for VRAM read/write lda #^level1_pal2_data ldx #.LOWORD(level1_pal2_data) ldy #$0400 ; 32 bytes * 32 tiles jsr svmw_load_vram ;============================= ; Init sprites to be offscreen jsr svmw_move_sprites_offscreen ;============================= ; Set our sprite active ; assume 544 byte sprite table in $0200 sep #$20 ; mem/A = 8 bit .a8 ;================== ; setup ship sprite ; Xxxxxxxxx yyyyyyy cccccccc vhoo pppN ; lda #104 ; set shipx to 104 sta $0200 ; lda #192 ; set shipy to 192 sta $0201 stz $0202 ; set ship sprite to 0 lda #$20 ; no flip, priority 2, N=0 palette=0 ($20) sta $0203 ; X high bit = 0 for sprite 0 ; sprite size = 1 (larger) lda #%01010110 sta $0400 ;===================================== ; set sprites 8,9,10,11 to be missiles lda #12 ; sprite location 13 sta $0202 + 4*8 sta $0202 + 4*9 sta $0202 + 4*10 sta $0202 + 4*11 lda #$20 ; pal=0, priority=2, flip=none sta $0203 + 4*8 sta $0203 + 4*9 sta $0203 + 4*10 sta $0203 + 4*11 ;========================= ;========================= ; Enable sprites ;========================= ;========================= ; sssnnbbb ; sss = size (011 = 16x16 and 32x32) ; nn = name ; bbb = base selection lda #%01100000 sta $2101 jsr svmw_transfer_sprite ;====================== ; Setup the Video Modes ;====================== level1_setup_video: sep #$20 ; mem/A = 8 bit .a8 rep #$10 ; X/Y = 16 bit .i16 lda #$01 ; 8x8 tiles, Mode 1 sta $2105 lda #$13 ; Enable BG1,BG2, and sprites sta $212c stz $212d ; disable subscreen lda #$00 ; Disable NMI (VBlank Interrupt) and joypads sta $4200 ; ;========================== ; Setup VBLANK routine ;========================== ldx #level1_vblank stx vblank_vector lda #$81 ; Enable NMI (VBlank Interrupt) and joypads sta $4200 ; jsr svmw_fade_in ;=========================== ; init lookup tables ;=========================== lda #$01 sta SPRITE_HIGH_LOOKUP lda #$04 sta SHL2 lda #$10 sta SHL3 lda #$40 sta SHL4 ;==================== ; setup the high score ;===================== lda #$01 sta HISCORE_H lda #$00 sta HISCORE_L ; modestly make me the high scorer lda #'V' sta HISCORE_1 lda #'M' sta HISCORE_2 lda #'W' sta HISCORE_3 ;========================================================== ; START NEW GAME ;========================================================== do_new_game: ;; set up struct pointers ; ldx #.LOWORD(missile_0) ; setup missle struct pointer ; stx MISSILE_PL ; ldx #.LOWORD(enemy_0) ; setup enemy struct pointer ; stx ENEMY_PL ;; Clear BSS ldx #$0 clear_bss: stz start_bss,X inx cpx #end_bss-start_bss bne clear_bss ;; Init one-time vars stz star_scroll stz star_scroll_h lda #$8 sta SHIELDS ; shields start at 8 ; jsr update_shields lda #104 sta shipx ; shipx at start is 18 lda #$1 sta LEVEL ; start at level 1 stz SCOREL stz SCOREH ; jsr print_score new_level: ;======================== ; Setup various variables ;======================== lda #(PERFECT_AIM|PERFECT_SHIELDS|PERFECT_KILLS) sta BONUS_FLAGS ; set perfect shot/shield/enemies lda #$14 sta ENEMY_WAIT ; ??? stz BETWEEN_DELAY stz SHIPXADD ; clear shipxadd stz ENEMY_WAVE stz TOTAL_ENEMIES_OUT stz ENEMIES_SPAWNED stz ENEMY_TYPE ;====================== ; Print level on screen ;====================== ; lda #>(level_string_xy) ; sta STRINGH ; lda #<(level_string_xy) ; sta STRINGL ; jsr print_text_xy ; ldx #20 ; jsr wait_X_100msec ; pause for 3 seconds ; bit KEYRESET ; clear keyboard ;/========================\ ;+ + ;+ MAIN LEVEL1 LOOP + ;+ + ;\========================/ .a8 .i16 level1_loop: wai ; wait for interrupt ; ================================ ; put out new enemies (if needed) ; ================================ inc BETWEEN_DELAY ; inc how long we've delayed lda BETWEEN_DELAY ; load it in cmp ENEMY_WAIT ; have we waited long enough? beq reset_delay jmp move_enemies ; if not, go on to movement reset_delay: ; delay==wait, so attempt to put out new enemy lda BETWEEN_DELAY and #$1 sta BETWEEN_DELAY ; reset delay ; special case for boss lda #$9 ; if boss, don't keep track of cmp ENEMY_TYPE ; how many enemies were spawned bne not_boss_dont_clear lda #$1 ; store 1 so we don't increment wave sta ENEMIES_SPAWNED not_boss_dont_clear: ; see if we are at a new wave ; basically, if 16 have been spawned, change lda ENEMIES_SPAWNED and #$0f bne same_enemy_type ; if not 16 gone by, move on ;======================= ; change the enemy type inc ENEMIES_SPAWNED jsr random_number and #$7 ; get a random number 0-7 sta ENEMY_TYPE inc ENEMY_WAVE lda ENEMY_WAVE ; have we enough waves to reach boss? cmp #WAVES_TILL_BOSS bne not_boss_yet lda #$8 sta ENEMY_TYPE not_boss_yet: ; set various constants ; these may be overriden later lda #20 sec sbc LEVEL sta ENEMY_WAIT ; enemy_wait=20-level ; set kind and init x to be random by default lda #$ff sta CURRENT_ENEMY_KIND sta CURRENT_INIT_X same_enemy_type: ; find empty enemy slot ldy #$20 ; point to enemies[0] find_empty_enemy: jsr is_sprite_active bcc add_enemy iny cpy #($20+NUM_ENEMIES) bne find_empty_enemy jmp move_enemies ; no empty, slots, move on add_enemy: ;============================================== ; First see if we must wait for enemy to clear ; types 2 and 8 lda ENEMY_TYPE cmp #$2 bne check_type_8 lda TOTAL_ENEMIES_OUT beq change_to_type_3 jmp move_enemies change_to_type_3: lda #$3 sta ENEMY_TYPE jsr random_number and #$8 sta CURRENT_ENEMY_KIND jsr random_number and #$1f ; mask off so 0-31 clc adc #$2 asl A sta CURRENT_INIT_X jmp setup_enemy_defaults check_type_8: cmp #$8 beq before_boss_stuff jmp check_type_9 before_boss_stuff: ;====================== ; before boss stuff lda TOTAL_ENEMIES_OUT beq prepare_for_boss jmp move_enemies prepare_for_boss: ;=============== ; HANDLE BONUSES ;=============== ; Print "BONUS POINTS" ; lda #>bonus_string ; sta STRINGH ; lda #bonus_shields ; sta STRINGH ; lda #bonus_kills ; sta STRINGH ; lda #bonus_aim ; sta STRINGH ; lda #no_bonus_string ; sta STRINGH ; lda #34 lda CURRENT_INIT_X bpl store_init_x jsr random_number and #$1f clc adc #$2 asl store_init_x: sta $200,X ; store x value at $200+(Y*4) ; enemy_y is always 0 by default inx ; store y value at $201+(Y*4) lda #$0 sta $200,X pla ; pull enemy type off stack inx ; store SPRITE value to $202+(Y*4) sta $200,X lda #$24 ; noflip, pal2, priority=2 inx sta $200,X ; store paramaters to $203+(Y*4) ; X = (Y*4)+3 lda #$24 sta extra_sprite,X ; ymin inx sta extra_sprite,X ; xmin inx stz extra_sprite,X ; yadd lda #$2 inx stz extra_sprite,X ; xadd ;=========================================== ; Enemy specific inits ; lda ENEMY_TYPE ; beq enemy_type_0 ; cmp #$1 ; beq enemy_type_1 ; jmp enemy_type_2 enemy_type_0: enemy_type_1: ;================================ ; ENEMY TYPE 0 and 1 ; diagonal, no wait ; movement proportional to level lda LEVEL ; xadd = level sta extra_sprite,X inx ; point to yadd lsr A ora #$1 sta extra_sprite,X ; yadd = level/2 jmp move_enemies enemy_type_2: ;===================== ; Enemy Type 2 ; just a place-holder ; waits for enemies to die then moves on to 3 ; cmp #$2 ; bne enemy_type_3 ; jmp move_enemies enemy_type_3: ; cmp #$3 ; bne enemy_type_4 ;====================== ; Enemy type 3 ; lda #$1 ; sta (ENEMY_PL),Y ; xadd=1 ; iny ; lda LEVEL ; sta (ENEMY_PL),Y ; yadd=level ; jmp move_enemies enemy_type_4: ; cmp #$4 ; bne enemy_type_5 ;========================= ; Enemy Type 4 ; Horizontal, then fall ; lda #$2 ; sta (ENEMY_PL),Y ; xadd = 2 ; iny ; jsr random_number ; ora #$80 ; set negative ; sta (ENEMY_PL),y ; yadd = -(random%128) ; this means bop back and forth a random ; time, then drop ; jmp move_enemies enemy_type_5: ; cmp #$5 ; bne enemy_type_6 ;======================== ; Enemy Type 5 ; "wiggle" ; lda #$1 ; sta (ENEMY_PL),y ; xadd=1 ; iny ; lda LEVEL ; sta (ENEMY_PL),y ; yadd=2 ; iny ; jsr random_number ; and #$0f ; clc ; adc #$2 ; sta (ENEMY_PL),y ; xmin=(rand%16)+2 ; dey ; yadd ; dey ; xadd ; dey ; y ; dey ; x ; asl A ; sta (ENEMY_PL),y ; iny ; y ; iny ; xadd ; iny ; yadd ; iny ; xmin ; jsr random_number ; and #$0f ; clc ; adc (ENEMY_PL),Y ; adc #$02 ; iny ; sta (ENEMY_PL),Y ; xmax = xmin+(rand%16)+2 ; jmp move_enemies enemy_type_6: ; cmp #$6 ; beq enemy_type_7 ; cmp #$7 ; beq enemy_type_7 ; jmp enemy_type_8 enemy_type_7: ;===================== ; Enemy Types 6+7 ; "Rain" ; jsr random_number ; and #6 ; bne no_use_own_x ; dey ; y ; dey ; x ; lda shipx ; cmp #$2 ; bpl shipx_ok ; lda #$2 ; stupid bug where gets stuck is < xmin shipx_ok: ; asl A ; sta (ENEMY_PL),Y ; one-in-four chance we use shipx as X ; iny ; y ; iny ; xadd no_use_own_x: ; lda #$0 ; sta (ENEMY_PL),Y ; xadd=0 ; iny ; lda #$1 ; sta (ENEMY_PL),Y ; yadd = 1 ; jmp move_enemies enemy_type_8: enemy_type_9: ;====================== ; Things flung by boss ; dey ; y ; dey ; x ; lda BOSS_X ; clc ; adc #$5 ; asl A ; sta (ENEMY_PL),Y ; enemy_x=boss_x+5 ; iny ; lda #$3 ; asl A ; asl A ; sta (ENEMY_PL),Y ; enemy_y=3 ; iny ; lda #$0 ; sta (ENEMY_PL),Y ; xadd=0 ; iny ; lda #$2 ; sta (ENEMY_PL),Y ; yadd=2 move_enemies: ;============================================== ; Move Enemies! (first thing, if no new added) ;============================================== ; ldy #$0 ; point to enemies[0] handle_enemies: ; tya ; pha ; store y on stack ; lda (ENEMY_PL),Y ; get enemy[y].out ; bne load_enemy_zero_page ; if enemy.out then we are good ; jmp skip_to_next_enemy ; enemy is not out, so skip to next ;========================================== ; load this enemy stuff into zero page for ; easier access ;========================================== load_enemy_zero_page: ; ldx #ENEMY_EXPLODING load_to_zero_page: ; iny ; point to exploding ; lda (ENEMY_PL),Y ; sta 0,X ; store to zero page ; inx ; cpx #(ENEMY_XMAX+1) ; see if reached end ; bne load_to_zero_page ; if not keep copying ;================================ ; skip all movement and collision ; if exploding ;================================ ; lda ENEMY_EXPLODING ; beq move_enemy_x ; jmp draw_enemy ;================================ ; Start the enemy movement engine ;================================ ;======== ; Move X ;======== move_enemy_x: ; clc ; lda ENEMY_X ; X ; adc ENEMY_XADD ; x+=xadd ; sta ENEMY_X ; lsr A ; cmp ENEMY_XMIN ; are we less than xmin? ; bmi switch_dir_enemy_x ; if so, switch direction ; cmp ENEMY_XMAX ; are we greater than xmax? ; bpl switch_dir_enemy_x ; if so, switch direction ; jmp move_enemy_y switch_dir_enemy_x: ; switch X direction ; lda #$0 ; load zero ; sec ; sbc ENEMY_XADD ; 0 - ENEMY_XADD ; sta ENEMY_XADD ; store it back out, negated ; jmp move_enemy_x ; re-add it in ;======== ; Move Y ;======== move_enemy_y: ; lda #$0 ; load in zero ; cmp ENEMY_YADD ; compare to YADD ; bmi no_y_special_case ; if minus, we have special case ; inc ENEMY_YADD ; bne done_enemy_y ; lda #$0 ; sta ENEMY_XADD ; lda #$2 ; sta ENEMY_YADD ; increment y ; is it > 0? ; if not keep going ; if so, yadd=level*2 ; jmp done_enemy_y no_y_special_case: ; clc ; lda ENEMY_Y ; get Y ; adc ENEMY_YADD ; y+=yadd ; sta ENEMY_Y ; store back out ; lsr A ; lsr A ; cmp #$12 ; is y<=12? ; bmi done_enemy_y ; if so no need to do anything ; beq done_enemy_y ; off screen ; pla ; pop saved Y off stack ; tay ; pha ; push y back on stack ; lda #$0 ; sta (ENEMY_PL),Y ; set enemy[i].out=0 ; dec TOTAL_ENEMIES_OUT ; lda BONUS_FLAGS ; and #<(~PERFECT_KILLS) ; sta BONUS_FLAGS ; jmp skip_to_next_enemy ; skip to next enemy done_enemy_y: ;=============== ; Done Movement ;=============== ;====================== ; Check for Collisions ;====================== ;================================== ; Check ENEMY <> MISSILE collision ;================================== check_enemy_missile_collision: ; ldy #$0 ; sty YSAV check_missile_loop: ; lda (MISSILE_PL),Y ; beq missile_not_out ; iny ; point to missile.x ; lda (MISSILE_PL),Y ; load missile.x ; sta COL_X1 ; sta COL_X2 ; lda ENEMY_X ; lsr A ; sta COL_X3 ; clc ; adc #3 ; sta COL_X4 ; jsr check_inside ; bcc missile_done x_in_range: ; iny ; lda (MISSILE_PL),Y ; load missile.y ; sta COL_X3 ; clc ; adc #2 ; sta COL_X4 ; lda ENEMY_Y ; lsr A ; lsr A ; sta COL_X1 ; clc ; adc #1 ; sta COL_X2 ; jsr check_inside ; bcc missile_done horrible_explosion: ; clear missile ; ldy YSAV ; lda #$0 ; sta (MISSILE_PL),Y ; clear enemy ; lda #$1 ; sta ENEMY_EXPLODING ; lda #$40 ; sta ENEMY_KIND ; jsr inc_score ; jmp draw_enemy missile_done: missile_not_out: ; ldy YSAV ; iny ; iny ; iny ; sty YSAV ; cpy #(NUM_MISSILES*3) ; bne check_missile_loop ;================================= ; Done missile <> enemy collision ;================================= ;==================================== ; check for ship <-> enemy collision ;==================================== ; lda shipx ; sta COL_X3 ; clc ; adc #8 ; sta COL_X4 ; big check is shipx - shipx+8 ; lda ENEMY_X ; lsr A ; sta COL_X1 ; clc ; adc #2 ; sta COL_X2 ; small check enemy_x - enemy_x+2 ; jsr check_inside ; check if overlap ; bcc draw_enemy ; if not, move ahead ; lda #16 ; sta COL_X3 ; lda #18 ; sta COL_X4 ; big check is 16 - 18 ; lda ENEMY_Y ; lsr A ; lsr A ; sta COL_X1 ; clc ; adc #$1 ; sta COL_X2 ; little check is enemy_y - enemy_y+1 ; jsr check_inside ; check if overlap ; bcc draw_enemy ; if not, move ahead ; make the enemy explode ; lda #$1 ; sta ENEMY_EXPLODING ; lda #$40 ; sta ENEMY_KIND ; dec SHIELDS ; jsr update_shields ; move shields down ; lda #<(~PERFECT_SHIELDS) ; (~PERFECT_SHIELDS) ; and BONUS_FLAGS ; remove perfect shield bonus ; sta BONUS_FLAGS ;===================================== ; Done ship <> enemy collision detect ;===================================== draw_enemy: ; See if the enemy is currently exploding ; if so, do explosion stuff check_enemy_explode: ; lda ENEMY_EXPLODING ; load enemy[i].exploding ; beq not_exploding ; if 0 then not exploding handle_exploding: ; jsr click ; make some noise ; clc ; lda ENEMY_KIND ; move to next step in explosion ; adc #$4 ; sta ENEMY_KIND ; cmp #$58 ; have we cycles through explosion? ; bne draw_enemy_sprite ; if not, we are still exploding ; dec TOTAL_ENEMIES_OUT ; total_enemies_out-- ; pla ; tay ; load y ; pha ; lda #$0 ; enemy[i].out=0 ; sta (ENEMY_PL),Y ; jmp skip_to_next_enemy ; point to enemies_x ; goto enemies_xy not_exploding: draw_enemy_sprite: ; point to proper sprite ; lda #>enemy_sprite0 ; point to the missile sprite ; sta STRINGH ; lda #boss_sprite ; sta STRINGH ; lda #smoke_sprite0 ; point to the missile sprite ; sta STRINGH ; lda #laser_sprite0 ; point to the missile sprite ; sta STRINGH ; lda #smoke_sprite0 ; point to the missile sprite ; sta STRINGH ; lda #shields_string ; sta STRINGH ; lda #score_string ; sta STRINGH ; lda #level_string ; sta STRINGH ; lda #game_over_string ; sta STRINGH ; lda #(score_string+31) ; sta STRINGH ; lda #<(score_string+31) ; sta STRINGL jsr print_high_score ; jsr HOME ; print new high score message ; lda #>new_high_score_string ; sta STRINGH ; lda #high_score_string ; sta STRINGH ; lda #shields_string ; sta STRINGH ; lda #(score_string+7) ; sta STRINGH ; lda #<(score_string+7) ; sta STRINGL ; tya ; pha ; save Y on stack ; ldy #$0 ; lda SCOREH ; sta BCD_BYTEH ; lda SCOREL ; sta BCD_BYTE ; jsr print_bcd_word ; pla ; restore Y ; tay rts ;====================== ; print high_score ;====================== ; location to output to in STRINGH/STRINGL print_high_score: ; tya ; pha ; save Y on stack ; ldy #$0 ; lda HISCORE_H ; sta BCD_BYTEH ; lda HISCORE_L ; sta BCD_BYTE ; jsr print_bcd_word ; pla ; restore Y ; tay rts ;========================================================== ; check inside ;========================================================== ; Simple collision detection. Have small line x1<->x2 ; Want to see if it overlaps long line x3<---------->x4 ; so: ; if ((x1>x3)&&(x1x3) && (x2