A.N.A.L.O.G. Magazine 1989 February/89_feb.atr/prog.src

Text File | 2023-02-26 | 15KB | 1 lines

 org $1FFD¢¢begining¢ JMP start¢¢¢ include d:chset.src¢¢¢ include d:terrain.src¢¢¢title_memory = $5000¢pause_memory = $6800¢screen_memory = $7400¢pmbase = $7800¢play1 = pmbase+$0500¢play2 = pmbase+$0600¢play3 = pmbase+$0700¢starfield = pmbase¢¢¢display_list¢ DB $30,$30,$70,$F0¢         ¢; space¢ DB $42¢ DW viewport¢¢ DB $42¢ DW screen_memory¢ DB $02,$02,$02,$02,$02,$02,$02,$02¢ DB $02,$02,$02,$02,$02¢           ¢; horizon¢ DB $44¢ DW horizon¢               ¢; landscape¢scroll_area¢ DB $4F¢ DW terrain_data¢ DB $0F,$0F,$0F,$0F,$0F,$0F,$0F,$0F¢ DB $0F,$0F,$0F,$0F,$0F,$0F,$0F,$0F¢ DB $0F,$0F,$0F,$0F,$0F,$0F,$0F,$0F¢ DB $0F,$0F,$0F,$0F,$0F,$0F,$00¢¢; control panel¢ DB $42¢ DW control_panel¢ DB $00,$02,$02,$00,$02¢¢ DB $41¢ DW display_list¢ ¢¢start¢ LDA #LOW busted¢ STA $02¢ LDA #HIGH busted¢ STA $03¢ LDA #$02¢ STA $09¢ LDA #$00¢ STA $244¢ STA toggle¢ STA pointer¢ STA $D4¢ LDA #$01¢ STA number_of_ships¢ LDA #$03¢ STA $D20F¢ STA $D01D¢ LDA #LOW kb_int¢ STA $0208¢ LDA #HIGH kb_int¢ STA $0209¢ LDA #$40¢ STA $D20E¢ LDA #HIGH pmbase¢ STA $D407¢ LDA #$80¢ STA $D40E¢ LDA #$3E¢ STA $D400¢¢ JSR clr_pause_display¢¢ JSR set_up_letters¢¢main_program¢ JSR wait_for_start¢¢ JSR vb_wait¢ LDA #$00¢ STA $D400¢¢ LDA #LOW display_list¢ STA $D402¢ LDA #HIGH display_list¢ STA $D403¢¢ LDA #LOW dli¢ STA $200¢ LDA #HIGH dli¢ STA $201¢¢ LDA #$DE¢ STA $D013¢ LDA #$3C¢ STA $D014¢ LDA #$8C¢ STA $D015¢ JSR pm_init¢¢ LDX #$04¢loop1¢ LDA colours,X¢ STA $D016,X¢ DEX¢ BPL loop1¢¢ JSR clr_screen¢¢ LDA #$00¢ STA released¢ STA chr_offset¢ STA $D208¢ LDX #$02¢horiz_init¢ STA p1x,X¢ DEX¢ BPL horiz_init¢¢ LDA #$FF¢ STA left_frame¢ STA right_frame¢ STA shakin¢ STA tons¢   ¢ LDA #$78¢ STA x_cursor¢ STA y_cursor¢          ¢ LDA #$10¢ STA shields+$01¢ STA shields+$02¢ LDX #$04¢loop70¢ STA score,X¢ DEX¢ BPL loop70¢¢ LDA #$11¢ STA shields¢¢ LDA #$04¢ STA llength¢¢ JSR vb_wait¢ LDA #$3E¢ STA $D400¢¢set_level¢ LDA number_of_ships¢ STA alive_ships¢ JSR init_fleet¢ JSR vb_waste¢¢loop3     ¢ JSR vb_wait¢ JSR handle_ship¢ JSR move_missiles¢ JSR vb_waste¢¢ JSR vb_wait ¢ JSR move_land¢ JSR move_cursor¢ JSR fade_em¢ JSR vb_waste¢       ¢ JSR vb_wait¢ JSR move_missiles¢ JSR effects¢ JSR play_keys¢ JSR vb_waste¢¢ JSR vb_wait  ¢ JSR move_land     ¢ JSR move_cursor¢ JSR fade_em¢ JSR vb_waste¢¢ LDA alive_ships¢ BNE loop3¢¢ JSR vb_wait¢ ¢ JSR up_wave¢ LDA number_of_ships¢ CMP #$FF¢ BEQ set_level¢ CLC ¢ ADC #$01¢ STA number_of_ships¢ BNE set_level¢¢colours¢ DB $00,$0C,$00,$46,$00¢¢llength¢ DB $00¢¢lcol_1¢ DB $44¢¢lcol_2¢ DB $4A¢¢up_wave¢ LDX #$01¢wave_loop¢ LDA wave,X¢ CLC¢ ADC #$01¢ CMP #$1A¢ BEQ next_wave_digit¢ STA wave,X¢ RTS¢next_wave_digit¢ LDA #$10¢ STA wave,X¢ DEX¢ BPL wave_loop¢ RTS¢¢¢init_fleet¢ LDX #$00¢init1loop¢ JSR init_ship¢ INX¢ CPX number_of_ships¢ BNE init1loop¢ RTS¢¢¢vb_wait¢ LDA $D40B¢ BNE vb_wait¢ RTS¢¢¢vb_waste¢ LDA $D40B¢ BEQ vb_waste¢ RTS¢                  ¢¢move_land¢ LDX llength¢ INX¢ CPX #$05¢ BNE set_llength¢ LDA lcol_1¢ PHA¢ LDA lcol_2¢ STA lcol_1¢ PLA¢ STA lcol_2¢ LDX #$01¢set_llength¢ STX llength¢ RTS¢¢¢dli¢ PHA¢ TXA¢ PHA¢ TYA¢ PHA¢¢ LDX #$8B ¢loop6¢ STX $D40A¢ STX $D018¢ DEX¢ CPX #$83¢ BNE loop6¢¢ LDA #$41¢ LDX #HIGH character_set¢ STA $D40A¢ STA $D01B              ¢ STX $D409¢         ¢ LDA starfield+$6F¢ PHA¢ LDX #$6E¢loop4¢ LDA starfield,X¢ STA $D40A¢ STA $D004¢ STA starfield+$01,X¢ STX $D012¢ DEX¢ BNE loop4¢ PLA¢ STA starfield+$01¢¢ LDA #$00¢ STA $D40A¢ STA $D004¢¢ LDA #$01¢ STA $D40A¢ STA $D01B¢          ¢ LDX #$08¢loop8¢ STX $D40A¢ DEX¢ BNE loop8¢¢ LDA lcol_1¢ LDY lcol_2¢ STA $D017¢ STY $D018¢ LDX llength¢lloop_1¢ STX $D40A¢ DEX¢ BNE lloop_1¢ STA $D018¢ STY $D017¢ LDX #$05¢lloop_2¢ STX $D40A¢ DEX¢ BNE lloop_2¢ STA $D017¢ STY $D018¢ LDX #$06¢lloop_3¢ STX $D40A¢ DEX¢ BNE lloop_3¢ STA $D018¢ STY $D017¢ LDX #$07¢lloop_4¢ STX $D40A¢ DEX ¢ BNE lloop_4¢ STA $D017¢ STY $D018¢ LDX #$08¢lloop_5¢ STX $D40A¢ DEX¢ BNE lloop_5¢ LDX llength¢ CPX #$04¢ BEQ lskip_1¢ STA $D018¢ STY $D017¢lloop_6¢ STX $D40A¢ INX¢ CPX #$04¢ BNE lloop_6¢lskip_1¢ LDA #$0C¢ STA $D40A¢ STA $D017¢ LDX #$8B¢ LDA #$E0¢ STA $D40A¢ STX $D018¢ STA $D409¢ DEX¢¢loop7¢ STX $D40A¢ STX $D018¢ DEX¢ CPX #$83¢ BNE loop7¢¢ LDA #$00¢ STA $D40A¢ STA $D017¢¢ LDX #$CB¢loop9¢ STX $D40A¢ STX $D018¢ STX $D40A¢ DEX¢ CPX #$C3¢ BNE loop9¢¢ LDA #$0C¢ STA $D40A¢ STA $D017¢¢ LDX #$8B¢loop11¢ STX $D40A¢ STX $D018¢ DEX¢ CPX #$83¢ BNE loop11¢¢ PLA¢ TAY¢ PLA¢ TAX¢ PLA¢ RTI       ¢¢¢viewport¢ DB 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0  ¢ DB 214,246,233,229,247¢ DB 240,239,242,244,194¢ DB 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0¢¢control_panel                    ¢ DB 0,0,0,0,0,0,0,0,0,0,0,0¢ DB 214,227,239,238,244,242,239,236¢ DB 128,240,225,238,229,236,194¢ DB 0,0,0,0,0,0,0,0,0,0,0,0,0¢¢ DB 0,0,0,0,0,0,0¢ DB 51,'core',0,0,0,0,0¢ DB 51,'hields',0,0,0,0,0¢ DB 55,'ave'¢ DB 0,0,0,0,0,0,0¢¢ DB 0,0,0,0,0,0,0¢ DB 16,16,16,16,16,0,0,0,0,0¢ DB 0,17,16,16,0,5,0,0,0,0,0,0¢ DB 0,16,17,0¢ DB 0,0,0,0,0,0,0¢¢ DB 0,0,0,0,0,0,0,0,0¢ DB 48,'rogrammed',0,34,'y',0¢ DB 48,'aul',0,44,'ay'¢ DB 0,0,0,0,0,0,0,0,0¢¢score = control_panel+87¢shields = control_panel+98¢wave = control_panel+110¢¢¢evaluate_address¢¢; take the coordinates x,y in $F0,$F1¢; and return the screen address in¢; $CC,$CD¢¢ TXA¢ PHA¢¢; first evaluate 40*y¢¢ LDA #$00¢ STA $CD¢ LDA $F1¢¢ ASL A   ; 2*y¢ ROL $CD      ¢ ASL A   ; 4*y¢ ROL $CD      ¢ ASL A   ; 8*y¢ ROL $CD¢¢ STA $CE ; save 8*y¢ LDX $CD¢ STX $CF¢¢ ASL A   ; 16*y¢ ROL $CD¢ ASL A   ; 32*y¢ ROL $CD¢¢ CLC     ; add 32*y and 8*y¢ ADC $CE                   ¢ STA $CC¢ LDA $CD¢ ADC $CF¢ STA $CD¢¢; now add in x¢ ¢ LDA $CC¢ CLC¢ ADC $F0¢ STA $CC¢ BCC skip2¢ INC $CD¢¢skip2¢¢; and add screen memory¢¢ LDA $CC¢ CLC¢ ADC #LOW screen_memory¢ STA $CC¢ LDA $CD¢ ADC #HIGH screen_memory¢ STA $CD¢¢ PLA¢ TAX¢¢; and return¢¢ RTS¢¢¢draw_big_ship¢¢; draw a big space ship at¢; coordinates x,y specified in $F0,¢; $F1¢¢ JSR evaluate_address¢¢ LDA #$09      ¢ CLC¢ ADC chr_offset¢ LDY #$05¢loop20¢ STA ($CC),Y¢ SEC¢ SBC #$01¢ DEY¢ BPL loop20¢¢ LDA #$0F ¢ CLC¢ ADC chr_offset¢ LDY #$2D¢loop21¢ STA ($CC),Y¢ SEC¢ SBC #$01¢ DEY     ¢ CPY #$27¢ BNE loop21¢¢ RTS¢¢¢draw_medium_ship¢¢; draw a medium space ship at¢; coordinates x,y specified in $F0,¢; $F1¢¢ JSR evaluate_address¢¢ LDA #$13¢ CLC¢ ADC chr_offset¢ LDY #$03¢loop22¢ STA ($CC),Y¢ SEC¢ SBC #$01¢ DEY¢ BPL loop22¢¢ LDA #$17      ¢ CLC¢ ADC chr_offset¢ LDY #$2B¢loop23¢ STA ($CC),Y¢ SEC¢ SBC #$01¢ DEY¢ CPY #$27     ¢ BNE loop23¢¢ RTS¢¢¢draw_small_ship¢¢; draw a small space ship at¢; coordinates x,y specified in $F0,¢; $F1¢¢ JSR evaluate_address¢¢ LDA #$1A¢ CLC¢ ADC chr_offset¢ LDY #$02¢loop24¢ STA ($CC),Y¢ SEC¢ SBC #$01¢ DEY¢ BPL loop24¢¢ RTS¢¢¢erase_big_ship¢ LDA #$00¢¢¢over_big_write¢ PHA¢ JSR evaluate_address¢ PLA¢ LDY #$05¢loop30¢ STA ($CC),Y¢ DEY¢ BPL loop30¢ LDY #$2D¢loop31¢ STA ($CC),Y¢ DEY¢ CPY #$27¢ BNE loop31¢ RTS¢¢¢erase_middle_ship¢ LDA #$00¢¢¢over_middle_write¢ PHA¢ JSR evaluate_address¢ PLA¢ LDY #$03¢loop32¢ STA ($CC),Y¢ DEY¢ BPL loop32¢ LDY #$2B¢loop33¢ STA ($CC),Y¢ DEY¢ CPY #$27¢ BNE loop33¢ RTS¢¢ ¢erase_small_ship¢ LDA #$00¢¢over_small_write¢ PHA¢ JSR evaluate_address¢ PLA¢ LDY #$02¢loop34¢ STA ($CC),Y¢ DEY¢ BPL loop34¢ RTS¢¢¢init_ship¢ LDA $D20A¢ AND #$3F¢ CMP #$23¢ BPL init_ship¢ STA ship_x,X¢ LDA #$0E¢ STA ship_y,X¢ LDA #$FF¢ STA ship_direction,X¢ LDA #$20¢ STA ship_stage,X¢ LDA $D20A¢ AND #$7F¢ STA ship_counter,X¢ RTS¢¢¢wipe_ship¢ BNE test1¢ JMP erase_small_ship¢test1¢ CMP #$01¢ BNE test2¢ JMP erase_medium_ship¢test2¢ JMP erase_big_ship¢¢¢draw_ship¢ BNE test3¢ JMP draw_small_ship¢test3¢ CMP #$01¢ BNE test4¢ JMP draw_medium_ship¢test4¢ JMP draw_big_ship¢¢¢handle_ship¢ LDX #$00¢ STX wings¢¢main_loop¢ LDA ship_stage,X¢ CMP #$03¢ BMI move_ship¢¢ AND #$10¢ BNE dying¢        ¢ LDA ship_stage,X¢ AND #$20¢ BEQ next_ship¢¢ DEC ship_counter,X¢ BNE next_ship¢ LDA #$00¢ STA ship_stage,X¢ LDA #$09¢ STA ship_counter,X¢¢next_ship¢ INX ¢ CPX number_of_ships¢ BNE main_loop¢ RTS¢¢dying¢ DEC ship_counter,X¢ BMI dead¢    ¢ LDA #$17¢ STA chr_offset¢ LDA ship_x,X¢ STA $F0¢ LDA ship_y,X¢ STA $F1¢ LDA ship_stage,X¢ AND #$03¢ JSR draw_ship¢ LDA #$00¢ STA chr_offset¢ JMP next_ship¢¢dead¢ LDA ship_x,X¢ STA $F0¢ LDA ship_y,X¢ STA $F1¢ LDA ship_stage,X¢ AND #$03¢ JSR wipe_ship¢ LDA #$03¢ STA ship_stage,X¢ DEC alive_ships¢ JMP next_ship¢¢¢move_ship¢ LDA ship_x,X¢ STA $F0¢ LDA ship_y,X¢ STA $F1¢ LDA ship_stage,X¢ JSR wipe_ship¢¢ DEC ship_counter,X¢ BNE skip10¢¢ LDA #$09¢ STA ship_counter,X¢ INC ship_stage,X¢ LDA ship_stage,X¢ CMP #$03¢ BMI skip10¢           ¢ JSR down_shields¢ LDA #$04¢ STA shakin¢ JSR init_ship¢ JMP next_ship   ¢¢skip10¢ LDA ship_y,X¢ CLC¢ ADC ship_direction,X¢ STA ship_y,X¢ STA $F1¢ STA wings¢ BNE skip11¢ LDA #$01¢ STA ship_direction,X¢¢skip11¢ LDA $D20A¢ CMP #$19¢ BCS skip12¢ LDA ship_x,X¢ BEQ draw_it¢ DEC ship_x,X¢ BPL draw_it¢¢skip12¢ LDA $D20A¢ CMP #$19¢ BCS draw_it¢ LDA ship_x,X¢ CMP #$22¢ BEQ draw_it¢ INC ship_x,X¢¢draw_it¢ LDA ship_x,X¢ STA $F0¢ LDA ship_stage,X¢ JSR draw_ship¢ JMP next_ship¢¢¢move_cursor¢ LDA $D010¢ BNE no_fire¢¢ LDA released¢ BEQ proceed¢¢ LDA #$00¢ STA released¢¢try_left¢ LDA left_frame¢ BPL try_right¢ JMP fire_left_missile¢¢try_right¢ LDA right_frame¢ BPL proceed¢ JMP fire_right_missile¢¢no_fire¢ STA released¢¢proceed¢ LDY #$0F¢ LDX y_cursor¢ LDA #$00¢loop50¢ STA play1,X¢ INX¢ DEY¢ BPL loop50¢¢ LDA $D300¢ AND #$0F¢ STA $CC¢ ¢ LDX toggle¢ BEQ try0¢     ¢ LDX #$00¢ STX $EF¢ LSR A¢ ROL $EF   ¢ LSR A¢ ROL $EF¢ LDA $CC¢ AND #$FC¢ ORA $EF¢ STA $CC¢ ¢try0¢ LSR $CC¢ BCS try1¢ LDA y_cursor¢ SEC¢ SBC #$08¢ STA y_cursor¢¢try1¢ LSR $CC¢ BCS try2¢ LDA y_cursor¢ CLC¢ ADC #$08¢ STA y_cursor¢¢try2¢ LSR $CC¢ BCS try3¢ LDA x_cursor¢ SEC¢ SBC #$08¢ STA x_cursor¢¢try3¢ LSR $CC¢ BCS check1¢ LDA x_cursor¢ CLC¢ ADC #$08¢ STA x_cursor¢¢check1¢ LDA x_cursor¢ CMP #$30¢ BCS check2¢ LDA #$30¢ STA x_cursor¢ BPL check3¢¢check2¢ CMP #$C9¢ BCC check3¢ LDA #$C8¢ STA x_cursor¢¢check3¢ LDA y_cursor¢ CMP #$28¢ BCS check4¢ LDA #$28¢ STA y_cursor¢ BPL draw_cursor¢¢check4¢ CMP #$B1¢ BCC draw_cursor¢ LDA #$B0¢ STA y_cursor¢ ¢draw_cursor¢ LDY #$0F¢ LDX y_cursor¢loop51¢ LDA cross_hair,Y¢ STA play1,X¢ INX¢ DEY¢ BPL loop51¢¢ LDA x_cursor¢ STA $D001¢ STA p1x¢ ¢ RTS¢¢cross_hair¢ DB 0,84,146,146,16,16,16,238¢ DB 238,16,16,16,146,146,84,0¢¢x_cursor = $F2¢y_cursor = $F3¢¢¢fire_left_missile¢ LDA x_cursor¢ SEC¢ SBC #$30¢ LSR A¢ LSR A¢ LSR A¢ STA left_x_inc¢¢ LDA #$B0¢ SEC¢ SBC y_cursor¢ LSR A¢ LSR A¢ LSR A¢ STA left_y_dec¢¢set_left_fire¢ LDA #$08¢ STA left_frame¢ LDA #$30¢ STA x_left¢ LDA #$B0¢ STA y_left¢ LDA #$04¢ STA tons¢ JMP draw_left_missile¢¢¢move_left_missile¢ LDA left_frame¢ BPL left_is_live¢ RTS¢¢left_is_live¢ LDY #$0F¢ LDX y_left¢ LDA #$00¢loop60¢ STA play2,X¢ INX¢ DEY¢ BPL loop60¢¢ LDA x_left¢ CLC¢ ADC left_x_inc¢ STA x_left¢¢ LDA y_left¢ SEC¢ SBC left_y_dec¢ STA y_left¢¢ DEC left_frame¢ BMI left_burned_out¢¢¢draw_left_missile¢ LDY #$0F¢ LDX y_left¢loop61¢ LDA photon,Y¢ AND $D20A¢ STA play2,X¢ INX¢ DEY¢ BPL loop61¢ ¢ LDA x_left¢ STA $D002¢ STA p2x¢¢left_burned_out¢ RTS¢¢left_frame = $F4¢left_x_inc = $F5¢left_y_dec = $F6¢x_left = $F7¢y_left = $F8¢¢¢fire_right_missile¢ LDA #$C8¢ SEC¢ SBC x_cursor¢ LSR A¢ LSR A¢ LSR A¢ STA right_x_dec¢¢ LDA #$B0¢ SEC¢ SBC y_cursor¢ LSR A¢ LSR A¢ LSR A¢ STA right_y_dec¢¢ LDA #$08¢ STA right_frame¢ LDA #$C8¢ STA x_right¢ LDA #$B0¢ STA y_right¢ LDA #$04¢ STA tons¢ JMP draw_right_missile¢¢¢move_right_missile¢ LDA right_frame¢ BPL right_is_live¢ RTS¢¢right_is_live¢ LDY #$0F¢ LDX y_right¢ LDA #$00¢loop62¢ STA play3,X¢ INX¢ DEY¢ BPL loop62¢¢ LDA x_right¢ SEC¢ SBC right_x_dec¢ STA x_right¢¢ LDA y_right¢ SEC¢ SBC right_y_dec¢ STA y_right¢¢ DEC right_frame¢ BMI right_burned_out¢      ¢¢draw_right_missile¢ LDY #$0F¢ LDX y_right¢loop63¢ LDA photon,Y¢ AND $D20A¢ STA play3,X¢ INX¢ DEY¢ BPL loop63¢¢ LDA x_right¢ STA $D003¢ STA p3x¢¢right_burned_out¢ RTS¢    ¢right_frame = $F9¢right_x_dec = $FA¢right_y_dec = $FB¢x_right = $FC¢y_right = $FD¢released = $FE¢              ¢photon¢ DB 24,60,126,126,126,255,255,255¢ DB 255,255,255,126,126,126,60,24¢¢¢move_missiles¢ JSR test_left_missile¢ JSR test_right_missile¢ JSR move_left_missile¢ JMP move_right_missile¢¢¢check_missile_hit¢ SEC¢ SBC #$28¢ LSR A¢ LSR A¢ LSR A ¢ STA y_missile¢¢ LDA x_missile¢ SEC¢ SBC #$30¢ LSR A¢ LSR A¢¢ SEC¢ SBC ship_x,X¢ CLC¢ ADC #$01¢ BMI no_hit¢                ¢ PHA¢ LDA ship_stage,X¢ TAY¢ PLA¢ CMP x_ranges,Y¢ BPL no_hit¢¢ LDA y_missile¢ SEC¢ SBC ship_y,X¢ CLC¢ ADC #$01¢ BMI no_hit¢¢ CMP y_ranges,Y¢ BPL no_hit¢¢a_hit¢ LDA #$08¢ STA hitz¢ SEC¢ RTS¢¢no_hit¢ CLC¢ RTS¢¢x_ranges¢ DB $03,$04,$06¢¢y_ranges¢ DB $01,$02,$02¢¢x_missile = $E0¢y_missile = $E1¢¢¢test_left_missile¢ LDA left_frame¢ BEQ left1test¢ RTS¢¢left1test¢ LDX #$00¢¢left1loop¢ LDA ship_stage,X¢ CMP #$03¢ BMI left2test¢¢left1next¢ INX¢ CPX number_of_ships¢ BNE left1loop¢ RTS    ¢¢left2test¢ LDA x_left¢ STA x_missile¢ LDA y_left¢ JSR check_missile_hit¢ BCC left_miss¢¢left_hit¢ JSR up_shields¢ JSR up_score¢ LDA ship_stage,X¢ ORA #$10¢ STA ship_stage,X¢ LDA #$08¢ STA ship_counter,X¢ RTS¢¢left_miss¢ JMP left1next¢¢test_right_missile¢ LDA right_frame¢ BEQ right1test¢ RTS¢¢right1test  ¢ LDX #$00¢¢r1loop¢ LDA ship_stage,X¢ CMP #$03¢ BMI right2test¢¢r1next¢ INX¢ CPX number_of_ships¢ BNE r1loop¢ RTS¢¢right2test¢ LDA x_right¢ STA x_missile¢ LDA y_right¢ JSR check_missile_hit¢ BCC right_miss¢¢right_hit¢ JSR up_shields¢ JSR up_score¢ LDA ship_stage,X¢ ORA #$10¢ STA ship_stage,X¢ LDA #$08¢ STA ship_counter,X¢ RTS   ¢¢right_miss¢ JMP r1next¢¢chr_offset = $FF¢¢¢fade_em¢ LDX #$00¢¢fade_loop¢ LDA $D20A¢ AND #$03¢ TAY¢ LDA character_set+$0020,X¢ AND mask,Y¢ STA character_set+$00D8,X¢ INX¢ CPX #$B6¢ BNE fade_loop¢¢ RTS¢¢mask¢ DB $00,$0F,$F0,$FF¢¢¢number_of_ships = $E2¢alive_ships = $E3¢¢¢up_shields¢¢ LDA shields¢ CMP #$11¢ BEQ done1¢¢ LDA number_of_ships¢ SEC¢ SBC #$01¢ AND #$F8¢ LSR A¢ LSR A¢ LSR A¢ CMP #$04¢ BMI found_boost¢ LDA #$03¢¢found_boost¢ TAY¢ LDA lo_boosts,Y¢ STA lo_add¢ LDA hi_boosts,Y¢ STA hi_add¢¢ LDA shields+$02¢ CLC¢ ADC lo_add¢ CMP #$1A¢ BMI skip80¢¢ INC hi_add¢ SEC¢ SBC #$0A¢¢skip80¢ STA shields+$02¢ ¢ LDA shields+$01¢ CLC¢ ADC hi_add¢ CMP #$1A¢ BMI skip81¢           ¢ LDA #$11¢ STA shields¢ LDA #$10¢ STA shields+$01¢ STA shields+$02¢¢done1¢ RTS¢¢skip81¢ STA shields+$01¢ RTS¢¢lo_add = $E4¢hi_add = $E5¢¢lo_boosts¢ DB $02,$05,$00,$00¢¢hi_boosts¢ DB $00,$00,$01,$02¢¢¢up_score¢ LDY #$04¢ LDA score,Y¢ CLC¢ ADC #$05¢ CMP #$1A¢ BMI done3¢¢loop83¢ SEC¢ SBC #$0A¢ STA score,Y¢¢ DEY¢ BMI overflow¢¢ LDA score,Y¢ CLC¢ ADC #$01¢ CMP #$1A¢ BPL loop83¢¢done3¢ STA score,Y¢ RTS¢¢overflow¢ RTS¢¢¢down_shields¢ LDY #$02¢ LDA shields,Y¢ SEC¢ SBC #$04¢ CMP #$10¢ BPL done2¢¢loop82¢ CLC¢ ADC #$0A¢ STA shields,Y¢¢ DEY ¢ BMI no_shields¢¢ LDA shields,Y¢ SEC¢ SBC #$01¢ CMP #$10¢ BMI loop82¢¢done2¢ STA shields,Y¢ RTS¢¢no_shields¢ LDA #$10¢ STA shields¢ STA shields+$01¢ STA shields+$02¢¢game_over¢ JSR time_to_die¢ JSR off_sound¢ LDX #$03¢ LDA #$00¢off_saves¢ STA freqs,X¢ STA dists,X¢ DEX¢ BPL off_saves¢ LDX #$00¢ TXS¢ JMP main_program¢ ¢ include d:prog2.src¢¢¢ship_x¢¢ship_y = ship_x+$0100¢¢ship_direction = ship_y+$0100¢¢ship_stage = ship_direction+$0100¢¢ship_counter = ship_stage+$0100¢¢¢ end begining ¢