Game 1 Unit 10 of 64 1 hr learning time

Home Zones

Reach the top. Fill the homes. Score points. Respawn and repeat.

16% of Signal

Mark as complete Completed!

What You’re Building

Goals.

Stakes without a goal is just endless punishment. This unit adds 5 home zones at the top of the screen. Reach an empty home, it fills in, you score 50 points, and you respawn. Fill all 5 homes to complete a round and start again.

By the end of this unit:

5 home zones at top of screen
Reaching an empty home fills it
50 points per successful docking
Landing on filled home = death
Landing between homes = death
Fill all 5 to reset for next round

Unit 10 Screenshot

Home Zone Layout

The top row has 5 home slots, evenly spaced across the grid:

; Home Zone Constants
; 5 homes at top row, must fill all to complete round

; Home zone configuration
NUM_HOMES       equ 5
HOME_ROW        equ 0           ; Top row of grid
POINTS_PER_HOME equ 50

; Home X positions (grid coordinates)
; Each home is 2 cells wide
HOME_0_X        equ 2
HOME_1_X        equ 6
HOME_2_X        equ 10
HOME_3_X        equ 14
HOME_4_X        equ 18

; Colours
COLOUR_HOME     equ $0282       ; Dark green (gaps between homes)
COLOUR_HOME_LIT equ $03a3       ; Light green (empty home)
COLOUR_HOME_FILLED equ $0f80    ; Orange (filled home)

; Home state tracking (0 = empty, 1 = filled)
home_filled:    dc.w    0,0,0,0,0

Each home is 2 grid cells wide. The gaps between homes are dangerous—landing there kills the frog. Using words instead of bytes keeps alignment clean and makes comparisons straightforward.

The Check Home Routine

When the frog reaches row 0, we determine which home (if any) it landed on:

; Check Home Zone
; Detect which home frog has reached (if any)

check_home:
            ; Only check if at top row
            move.w  frog_grid_y,d0
            tst.w   d0
            bne     .not_home

            ; At top row - determine which home
            move.w  frog_grid_x,d0

            ; Check home 0 (X = 2-3)
            cmp.w   #HOME_0_X,d0
            blt.s   .not_home
            cmp.w   #HOME_0_X+2,d0
            blt.s   .home_0

            ; Check home 1 (X = 6-7)
            cmp.w   #HOME_1_X,d0
            blt.s   .not_home
            cmp.w   #HOME_1_X+2,d0
            blt.s   .home_1

            ; (continue for homes 2, 3, 4...)

            ; Between homes - death!
            bra     .death_between

.home_0:    moveq   #0,d1
            bra.s   .check_filled
.home_1:    moveq   #1,d1
            bra.s   .check_filled
            ; (etc...)

.check_filled:
            ; D1 = home index (0-4)
            lea     home_filled,a0
            add.w   d1,d1               ; *2 for word offset
            tst.w   0(a0,d1.w)
            bne.s   .death_filled       ; Already filled - death!

            ; Home is empty - fill it!
            move.w  #1,0(a0,d1.w)
            add.l   #POINTS_PER_HOME,score
            bsr     update_home_display
            bsr     reset_frog
            rts

.death_filled:
.death_between:
            bsr     trigger_death
            rts

.not_home:
            rts

The logic is straightforward: check if the X position falls within each home’s range. If it’s between homes, the frog dies. Landing on an already-filled home also kills the frog—this prevents players from repeatedly using the same safe spot.

Score Tracking

We use a 32-bit long word for the score:

score:          dc.l    0
POINTS_PER_HOME equ 50

; Adding points
add.l   #POINTS_PER_HOME,score

The score isn’t displayed yet—that comes in a later unit. For now, we just track it.

Round Completion

When all 5 homes are filled, we reset them for the next round:

check_round_complete:
    lea     home_filled,a0
    moveq   #NUM_HOMES-1,d0
    moveq   #0,d1               ; Count filled homes

.loop:
    tst.w   (a0)+
    beq.s   .not_complete
    addq.w  #1,d1
    dbf     d0,.loop

    ; All homes filled?
    cmp.w   #NUM_HOMES,d1
    bne.s   .not_complete

    ; Clear all homes for next round
    lea     home_filled,a0
    moveq   #NUM_HOMES-1,d0
.clear:
    clr.w   (a0)+
    dbf     d0,.clear

    bsr     update_home_display

.not_complete:
    rts

In a complete game, this is where you’d increase difficulty—faster cars, more obstacles. For now, we just reset.

Visual Feedback via Copper

We modify the Copper list to show filled homes in a different colour. Each home zone has its own colour value that we update:

; Update Home Display
; Modify Copper list colours to show filled homes

update_home_display:
            lea     home_filled,a0
            lea     home_colour_0,a1

            ; Home 0
            tst.w   (a0)+
            beq.s   .home0_empty
            move.w  #COLOUR_HOME_FILLED,(a1)
            bra.s   .home1
.home0_empty:
            move.w  #COLOUR_HOME_LIT,(a1)

.home1:
            lea     home_colour_1,a1
            tst.w   (a0)+
            beq.s   .home1_empty
            move.w  #COLOUR_HOME_FILLED,(a1)
            bra.s   .home2
.home1_empty:
            move.w  #COLOUR_HOME_LIT,(a1)

            ; (continue for homes 2, 3, 4...)

            rts

; Copper list with modifiable home colours:
copperlist:
            ; ... other setup ...

            ; Home zone row with horizontal colour changes
            dc.w    $2c07,$fffe
            dc.w    COLOR00,COLOUR_HOME     ; Gap

            dc.w    $2c4f,$fffe             ; Wait for home 0 X position
            dc.w    COLOR00
home_colour_0:
            dc.w    COLOUR_HOME_LIT         ; Modified at runtime

            dc.w    $2c5f,$fffe             ; End of home 0
            dc.w    COLOR00,COLOUR_HOME     ; Gap

            ; (continue for homes 1-4...)

The Copper changes colours mid-scanline to create distinct home zones. Filled homes appear orange, empty ones stay light green. The wait value $2c4f means: scanline $2c, horizontal position $4f. This lets us change colours within a single line.

Game Initialisation

We add an init_game routine that resets everything for a new game:

init_game:
    move.w  #START_LIVES,lives
    clr.l   score

    ; Clear all homes
    lea     home_filled,a0
    moveq   #NUM_HOMES-1,d0
.clear_homes:
    clr.w   (a0)+
    dbf     d0,.clear_homes

    bsr     update_home_display
    bsr     reset_frog
    rts

This is called at startup and when restarting after game over.

When to Check Homes

We only check for home docking when the frog is idle (not hopping or dying):

cmp.w   #STATE_DYING,frog_state
beq.s   .skip_collision
cmp.w   #STATE_IDLE,frog_state
bne.s   .skip_collision
bsr     check_home
bsr     check_collision
.skip_collision:

This ensures we only check at the moment the frog lands on a cell, not during animation.

Key Takeaways

Home zones create a goal beyond survival
State tracking per home enables progress
Round completion creates replay loops
Horizontal Copper waits enable per-home colours
Score variable tracks player progress
Filled home death prevents camping

The Code

;==============================================================================
; SIGNAL - A Frogger-style game for the Commodore Amiga
; Unit 10: Home Zones
;
; Stakes alone aren't enough—you need a goal. This unit adds 5 home zones at
; the top of the screen. Reach one, it fills in, you respawn. Fill all 5 to
; complete a round. Each successful docking scores 50 points.
;==============================================================================

;==============================================================================
; CONSTANTS
;==============================================================================

SCREEN_W        equ 40
SCREEN_H        equ 256
PLANE_SIZE      equ SCREEN_W*SCREEN_H

GRID_COLS       equ 20
GRID_ROWS       equ 13
CELL_SIZE       equ 16
GRID_ORIGIN_X   equ 48
GRID_ORIGIN_Y   equ 44
START_GRID_X    equ 9
START_GRID_Y    equ 12

HOP_FRAMES      equ 8
PIXELS_PER_FRAME equ 2
STATE_IDLE      equ 0
STATE_HOPPING   equ 1
STATE_DYING     equ 2
STATE_GAMEOVER  equ 3
DIR_UP          equ 0
DIR_DOWN        equ 1
DIR_LEFT        equ 2
DIR_RIGHT       equ 3
FROG_HEIGHT     equ 16
FROG_WIDTH      equ 16

DEATH_FRAMES    equ 30
FLASH_COLOUR    equ $0f00

NUM_CARS        equ 10
CAR_WIDTH       equ 2
CAR_WIDTH_PX    equ 32
CAR_HEIGHT      equ 12
CAR_STRUCT_SIZE equ 8

ROAD_ROW_FIRST  equ 7
ROAD_ROW_LAST   equ 11

; Lives system
START_LIVES     equ 3
LIFE_ICON_W     equ 1
LIFE_ICON_H     equ 8
LIFE_ICON_X     equ 8
LIFE_ICON_Y     equ 260
LIFE_ICON_SPACING equ 20

; Home zones
NUM_HOMES       equ 5
HOME_ROW        equ 0           ; Top row of grid
POINTS_PER_HOME equ 50

; Home X positions (grid coordinates): 2, 6, 10, 14, 18
; Each home is 2 cells wide (even column = start of home)
HOME_0_X        equ 2
HOME_1_X        equ 6
HOME_2_X        equ 10
HOME_3_X        equ 14
HOME_4_X        equ 18

; Colours
COLOUR_BLACK    equ $0000
COLOUR_HOME     equ $0282
COLOUR_HOME_LIT equ $03a3
COLOUR_HOME_FILLED equ $0f80    ; Orange for filled homes
COLOUR_WATER1   equ $0148
COLOUR_WATER2   equ $026a
COLOUR_MEDIAN   equ $0383
COLOUR_ROAD1    equ $0333
COLOUR_ROAD2    equ $0444
COLOUR_START    equ $0262
COLOUR_START_LIT equ $0373
COLOUR_FROG     equ $00f0
COLOUR_EYES     equ $0ff0
COLOUR_OUTLINE  equ $0000
COLOUR_CAR      equ $0f00
COLOUR_LIFE     equ $00f0

;==============================================================================
; HARDWARE REGISTERS
;==============================================================================

CUSTOM      equ $dff000

DMACONR     equ $002
VPOSR       equ $004
JOY1DAT     equ $00c

BLTCON0     equ $040
BLTCON1     equ $042
BLTAFWM     equ $044
BLTALWM     equ $046
BLTCPTH     equ $048
BLTBPTH     equ $04c
BLTAPTH     equ $050
BLTDPTH     equ $054
BLTSIZE     equ $058
BLTCMOD     equ $060
BLTBMOD     equ $062
BLTAMOD     equ $064
BLTDMOD     equ $066

COP1LC      equ $080
COPJMP1     equ $088
DMACON      equ $096
INTENA      equ $09a
INTREQ      equ $09c
COLOR00     equ $180
SPR0PTH     equ $120
SPR0PTL     equ $122
SPR1PTH     equ $124
SPR1PTL     equ $126
SPR2PTH     equ $128
SPR2PTL     equ $12a

;==============================================================================
; CODE SECTION
;==============================================================================

            section code,code_c

start:
            lea     CUSTOM,a5

            move.w  #$7fff,INTENA(a5)
            move.w  #$7fff,INTREQ(a5)
            move.w  #$7fff,DMACON(a5)

            bsr     clear_screen

            ; Set up bitplane pointer
            lea     screen_plane,a0
            move.l  a0,d0
            swap    d0
            lea     bplpth_val,a1
            move.w  d0,(a1)
            swap    d0
            lea     bplptl_val,a1
            move.w  d0,(a1)

            ; Initialise game
            bsr     init_game

            ; Set main sprite pointer (sprite 0 = frog)
            lea     frog_data,a0
            move.l  a0,d0
            swap    d0
            lea     sprpth_val,a1
            move.w  d0,(a1)
            swap    d0
            lea     sprptl_val,a1
            move.w  d0,(a1)

            ; Set up life icon sprites (sprites 1, 2, 3)
            bsr     setup_life_sprites

            bsr     update_sprite
            bsr     update_life_display

            ; Install copper list
            lea     copperlist,a0
            move.l  a0,COP1LC(a5)
            move.w  d0,COPJMP1(a5)

            ; Enable DMA
            move.w  #$87e0,DMACON(a5)

;==============================================================================
; MAIN LOOP
;==============================================================================

mainloop:
            bsr     wait_vblank

            ; Check game state
            cmp.w   #STATE_GAMEOVER,frog_state
            beq     .game_over_loop

            ; Normal game loop
            bsr     update_frog
            bsr     update_sprite

            bsr     erase_all_cars
            bsr     move_all_cars
            bsr     draw_all_cars

            cmp.w   #STATE_DYING,frog_state
            beq.s   .skip_collision
            cmp.w   #STATE_IDLE,frog_state
            bne.s   .skip_collision
            bsr     check_home
            bsr     check_collision
.skip_collision:

            bra     mainloop

.game_over_loop:
            ; Game over - wait for fire button to restart
            btst    #7,$bfe001
            bne.s   mainloop

            ; Restart game
            bsr     init_game
            bsr     update_life_display
            bsr     clear_screen

            bra     mainloop

;==============================================================================
; GAME INITIALISATION
;==============================================================================

init_game:
            move.w  #START_LIVES,lives
            clr.l   score

            ; Clear all homes
            lea     home_filled,a0
            moveq   #NUM_HOMES-1,d0
.clear_homes:
            clr.w   (a0)+
            dbf     d0,.clear_homes

            bsr     update_home_display
            bsr     reset_frog
            rts

;==============================================================================
; HOME ZONE DETECTION
;==============================================================================

;------------------------------------------------------------------------------
; CHECK_HOME - Check if frog has reached a home zone
;------------------------------------------------------------------------------
check_home:
            ; Only check if at top row
            move.w  frog_grid_y,d0
            tst.w   d0
            bne     .not_home

            ; At top row - determine which home
            move.w  frog_grid_x,d0

            ; Check home 0 (X = 2-3)
            cmp.w   #HOME_0_X,d0
            blt.s   .not_home
            cmp.w   #HOME_0_X+2,d0
            blt.s   .home_0

            ; Check home 1 (X = 6-7)
            cmp.w   #HOME_1_X,d0
            blt.s   .not_home
            cmp.w   #HOME_1_X+2,d0
            blt.s   .home_1

            ; Check home 2 (X = 10-11)
            cmp.w   #HOME_2_X,d0
            blt.s   .not_home
            cmp.w   #HOME_2_X+2,d0
            blt.s   .home_2

            ; Check home 3 (X = 14-15)
            cmp.w   #HOME_3_X,d0
            blt.s   .not_home
            cmp.w   #HOME_3_X+2,d0
            blt.s   .home_3

            ; Check home 4 (X = 18-19)
            cmp.w   #HOME_4_X,d0
            blt.s   .not_home
            cmp.w   #HOME_4_X+2,d0
            blt.s   .home_4

            ; Between homes - death!
            bra     .death_between

.home_0:    moveq   #0,d1
            bra.s   .check_filled
.home_1:    moveq   #1,d1
            bra.s   .check_filled
.home_2:    moveq   #2,d1
            bra.s   .check_filled
.home_3:    moveq   #3,d1
            bra.s   .check_filled
.home_4:    moveq   #4,d1

.check_filled:
            ; D1 = home index (0-4)
            lea     home_filled,a0
            add.w   d1,d1               ; *2 for word offset
            tst.w   0(a0,d1.w)
            bne.s   .death_filled       ; Already filled - death!

            ; Home is empty - fill it!
            move.w  #1,0(a0,d1.w)

            ; Add points
            add.l   #POINTS_PER_HOME,score

            ; Update display
            bsr     update_home_display

            ; Check if all homes filled
            bsr     check_round_complete

            ; Respawn frog
            bsr     reset_frog
            rts

.death_filled:
            ; Landed on filled home - death
            bsr     trigger_death
            rts

.death_between:
            ; Landed between homes (on lily pad gaps) - death
            bsr     trigger_death
            rts

.not_home:
            rts

;------------------------------------------------------------------------------
; CHECK_ROUND_COMPLETE - Check if all 5 homes are filled
;------------------------------------------------------------------------------
check_round_complete:
            lea     home_filled,a0
            moveq   #NUM_HOMES-1,d0
            moveq   #0,d1               ; Count filled homes

.loop:
            tst.w   (a0)+
            beq.s   .not_complete
            addq.w  #1,d1
            dbf     d0,.loop

            ; All homes filled - reset for next round
            cmp.w   #NUM_HOMES,d1
            bne.s   .not_complete

            ; Clear all homes for next round
            lea     home_filled,a0
            moveq   #NUM_HOMES-1,d0
.clear:
            clr.w   (a0)+
            dbf     d0,.clear

            bsr     update_home_display
            ; Could add bonus points here, increase speed, etc.

.not_complete:
            rts

;------------------------------------------------------------------------------
; UPDATE_HOME_DISPLAY - Update Copper colours to show filled homes
;------------------------------------------------------------------------------
update_home_display:
            lea     home_filled,a0
            lea     home_colour_0,a1

            ; Home 0
            tst.w   (a0)+
            beq.s   .home0_empty
            move.w  #COLOUR_HOME_FILLED,(a1)
            bra.s   .home1
.home0_empty:
            move.w  #COLOUR_HOME_LIT,(a1)

.home1:
            lea     home_colour_1,a1
            tst.w   (a0)+
            beq.s   .home1_empty
            move.w  #COLOUR_HOME_FILLED,(a1)
            bra.s   .home2
.home1_empty:
            move.w  #COLOUR_HOME_LIT,(a1)

.home2:
            lea     home_colour_2,a1
            tst.w   (a0)+
            beq.s   .home2_empty
            move.w  #COLOUR_HOME_FILLED,(a1)
            bra.s   .home3
.home2_empty:
            move.w  #COLOUR_HOME_LIT,(a1)

.home3:
            lea     home_colour_3,a1
            tst.w   (a0)+
            beq.s   .home3_empty
            move.w  #COLOUR_HOME_FILLED,(a1)
            bra.s   .home4
.home3_empty:
            move.w  #COLOUR_HOME_LIT,(a1)

.home4:
            lea     home_colour_4,a1
            tst.w   (a0)+
            beq.s   .home4_empty
            move.w  #COLOUR_HOME_FILLED,(a1)
            rts
.home4_empty:
            move.w  #COLOUR_HOME_LIT,(a1)
            rts

;==============================================================================
; LIFE DISPLAY
;==============================================================================

setup_life_sprites:
            ; Sprite 1
            lea     life_icon_1,a0
            move.l  a0,d0
            swap    d0
            lea     spr1pth_val,a1
            move.w  d0,(a1)
            swap    d0
            lea     spr1ptl_val,a1
            move.w  d0,(a1)

            ; Sprite 2
            lea     life_icon_2,a0
            move.l  a0,d0
            swap    d0
            lea     spr2pth_val,a1
            move.w  d0,(a1)
            swap    d0
            lea     spr2ptl_val,a1
            move.w  d0,(a1)

            ; Sprite 3
            lea     life_icon_3,a0
            move.l  a0,d0
            swap    d0
            lea     spr3pth_val,a1
            move.w  d0,(a1)
            swap    d0
            lea     spr3ptl_val,a1
            move.w  d0,(a1)

            rts

update_life_display:
            ; Life 1 (always show if lives >= 1)
            lea     life_icon_1,a0
            move.w  lives,d0
            cmp.w   #1,d0
            blt.s   .hide_life1
            move.w  #$1e20,$0(a0)
            move.w  #$2600,$2(a0)
            bra.s   .life2
.hide_life1:
            clr.l   (a0)

.life2:
            lea     life_icon_2,a0
            cmp.w   #2,d0
            blt.s   .hide_life2
            move.w  #$1e28,$0(a0)
            move.w  #$2600,$2(a0)
            bra.s   .life3
.hide_life2:
            clr.l   (a0)

.life3:
            lea     life_icon_3,a0
            cmp.w   #3,d0
            blt.s   .hide_life3
            move.w  #$1e30,$0(a0)
            move.w  #$2600,$2(a0)
            rts
.hide_life3:
            clr.l   (a0)
            rts

;==============================================================================
; COLLISION AND DEATH
;==============================================================================

check_collision:
            move.w  frog_grid_y,d0
            cmp.w   #ROAD_ROW_FIRST,d0
            blt     .no_collision
            cmp.w   #ROAD_ROW_LAST,d0
            bgt     .no_collision

            lea     car_data,a2
            moveq   #NUM_CARS-1,d7

.loop:
            move.w  2(a2),d1
            cmp.w   d0,d1
            bne.s   .next_car

            move.w  frog_pixel_x,d2
            move.w  (a2),d3

            move.w  d2,d4
            add.w   #FROG_WIDTH,d4
            cmp.w   d3,d4
            ble.s   .next_car

            move.w  d3,d4
            add.w   #CAR_WIDTH_PX,d4
            cmp.w   d2,d4
            ble.s   .next_car

            bsr     trigger_death
            bra.s   .no_collision

.next_car:
            lea     CAR_STRUCT_SIZE(a2),a2
            dbf     d7,.loop

.no_collision:
            rts

trigger_death:
            move.w  #STATE_DYING,frog_state
            move.w  #DEATH_FRAMES,death_timer
            move.w  #FLASH_COLOUR,flash_colour

            ; Decrement lives
            subq.w  #1,lives
            bsr     update_life_display

            rts

reset_frog:
            move.w  #START_GRID_X,frog_grid_x
            move.w  #START_GRID_Y,frog_grid_y
            move.w  #STATE_IDLE,frog_state
            clr.w   frog_anim_frame
            clr.w   joy_prev
            move.w  #COLOUR_BLACK,flash_colour
            bsr     grid_to_pixels
            rts

;==============================================================================
; CAR MANAGEMENT
;==============================================================================

erase_all_cars:
            lea     car_data,a2
            moveq   #NUM_CARS-1,d7

.loop:
            move.w  (a2),d0
            move.w  2(a2),d1
            bsr     calc_screen_addr
            bsr     wait_blit

            move.l  a0,BLTDPTH(a5)
            move.w  #SCREEN_W-CAR_WIDTH*2,BLTDMOD(a5)
            move.w  #$0100,BLTCON0(a5)
            move.w  #0,BLTCON1(a5)
            move.w  #(CAR_HEIGHT<<6)|CAR_WIDTH,BLTSIZE(a5)

            lea     CAR_STRUCT_SIZE(a2),a2
            dbf     d7,.loop
            rts

move_all_cars:
            lea     car_data,a2
            moveq   #NUM_CARS-1,d7

.loop:
            move.w  (a2),d0
            move.w  4(a2),d1
            add.w   d1,d0

            tst.w   d1
            bmi.s   .check_left
            cmp.w   #320,d0
            blt.s   .store
            sub.w   #320+32,d0
            bra.s   .store
.check_left:
            cmp.w   #-32,d0
            bgt.s   .store
            add.w   #320+32,d0
.store:
            move.w  d0,(a2)
            lea     CAR_STRUCT_SIZE(a2),a2
            dbf     d7,.loop
            rts

draw_all_cars:
            lea     car_data,a2
            moveq   #NUM_CARS-1,d7

.loop:
            move.w  (a2),d0
            move.w  2(a2),d1

            cmp.w   #-32,d0
            blt.s   .next
            cmp.w   #320,d0
            bge.s   .next

            bsr     calc_screen_addr
            bsr     wait_blit

            move.l  #car_gfx,BLTAPTH(a5)
            move.l  a0,BLTDPTH(a5)
            move.w  #$ffff,BLTAFWM(a5)
            move.w  #$ffff,BLTALWM(a5)
            move.w  #0,BLTAMOD(a5)
            move.w  #SCREEN_W-CAR_WIDTH*2,BLTDMOD(a5)
            move.w  #$09f0,BLTCON0(a5)
            move.w  #0,BLTCON1(a5)
            move.w  #(CAR_HEIGHT<<6)|CAR_WIDTH,BLTSIZE(a5)

.next:
            lea     CAR_STRUCT_SIZE(a2),a2
            dbf     d7,.loop
            rts

;==============================================================================
; FROG ROUTINES
;==============================================================================

update_frog:
            move.w  frog_state,d0

            cmp.w   #STATE_DYING,d0
            beq     .dying
            tst.w   d0
            beq     .idle
            bra     .hopping

.dying:
            subq.w  #1,death_timer
            bgt.s   .still_dying

            ; Death complete - check for game over
            tst.w   lives
            beq.s   .game_over

            ; Still have lives - respawn
            bsr     reset_frog
            bra     .done

.game_over:
            move.w  #STATE_GAMEOVER,frog_state
            bra     .done

.still_dying:
            move.w  death_timer,d0
            and.w   #4,d0
            beq.s   .flash_off
            move.w  #FLASH_COLOUR,flash_colour
            bra     .done
.flash_off:
            move.w  #COLOUR_BLACK,flash_colour
            bra     .done

.idle:
            bsr     read_joystick_edge
            tst.w   d0
            beq     .done

            btst    #8,d0
            beq.s   .not_up
            move.w  frog_grid_y,d1
            tst.w   d1
            beq.s   .not_up
            move.w  #DIR_UP,frog_dir
            bra.s   .start_hop
.not_up:
            btst    #0,d0
            beq.s   .not_down
            move.w  frog_grid_y,d1
            cmp.w   #GRID_ROWS-1,d1
            beq.s   .not_down
            move.w  #DIR_DOWN,frog_dir
            bra.s   .start_hop
.not_down:
            btst    #9,d0
            beq.s   .not_left
            move.w  frog_grid_x,d1
            tst.w   d1
            beq.s   .not_left
            move.w  #DIR_LEFT,frog_dir
            bra.s   .start_hop
.not_left:
            btst    #1,d0
            beq     .done
            move.w  frog_grid_x,d1
            cmp.w   #GRID_COLS-1,d1
            beq     .done
            move.w  #DIR_RIGHT,frog_dir

.start_hop:
            move.w  #STATE_HOPPING,frog_state
            clr.w   frog_anim_frame
            bra.s   .done

.hopping:
            addq.w  #1,frog_anim_frame
            move.w  frog_dir,d0

            cmp.w   #DIR_UP,d0
            bne.s   .hop_not_up
            sub.w   #PIXELS_PER_FRAME,frog_pixel_y
            bra.s   .check_done
.hop_not_up:
            cmp.w   #DIR_DOWN,d0
            bne.s   .hop_not_down
            add.w   #PIXELS_PER_FRAME,frog_pixel_y
            bra.s   .check_done
.hop_not_down:
            cmp.w   #DIR_LEFT,d0
            bne.s   .hop_not_left
            sub.w   #PIXELS_PER_FRAME,frog_pixel_x
            bra.s   .check_done
.hop_not_left:
            add.w   #PIXELS_PER_FRAME,frog_pixel_x

.check_done:
            cmp.w   #HOP_FRAMES,frog_anim_frame
            blt.s   .done

            move.w  frog_dir,d0
            cmp.w   #DIR_UP,d0
            bne.s   .end_not_up
            subq.w  #1,frog_grid_y
            bra.s   .snap
.end_not_up:
            cmp.w   #DIR_DOWN,d0
            bne.s   .end_not_down
            addq.w  #1,frog_grid_y
            bra.s   .snap
.end_not_down:
            cmp.w   #DIR_LEFT,d0
            bne.s   .end_not_left
            subq.w  #1,frog_grid_x
            bra.s   .snap
.end_not_left:
            addq.w  #1,frog_grid_x

.snap:
            bsr     grid_to_pixels
            move.w  #STATE_IDLE,frog_state

.done:
            move.w  flash_colour,flash_copper
            rts

;==============================================================================
; UTILITY ROUTINES
;==============================================================================

grid_to_pixels:
            move.w  frog_grid_x,d0
            mulu    #CELL_SIZE,d0
            add.w   #GRID_ORIGIN_X,d0
            move.w  d0,frog_pixel_x

            move.w  frog_grid_y,d0
            mulu    #CELL_SIZE,d0
            add.w   #GRID_ORIGIN_Y,d0
            move.w  d0,frog_pixel_y
            rts

read_joystick_edge:
            move.w  JOY1DAT(a5),d0
            move.w  d0,d1
            lsr.w   #1,d1
            eor.w   d1,d0

            move.w  joy_prev,d1
            not.w   d1
            and.w   d0,d1
            move.w  d0,joy_prev

            move.w  d1,d0
            rts

wait_vblank:
            move.l  #$1ff00,d1
.wait:
            move.l  VPOSR(a5),d0
            and.l   d1,d0
            bne.s   .wait
            rts

wait_blit:
            btst    #6,DMACONR(a5)
            bne.s   wait_blit
            rts

clear_screen:
            bsr.s   wait_blit
            move.l  #screen_plane,BLTDPTH(a5)
            move.w  #0,BLTDMOD(a5)
            move.w  #$0100,BLTCON0(a5)
            move.w  #0,BLTCON1(a5)
            move.w  #(SCREEN_H<<6)|SCREEN_W/2,BLTSIZE(a5)
            rts

calc_screen_addr:
            lea     screen_plane,a0
            move.w  d1,d2
            mulu    #CELL_SIZE,d2
            add.w   #GRID_ORIGIN_Y,d2
            mulu    #SCREEN_W,d2
            add.l   d2,a0
            move.w  d0,d2
            lsr.w   #3,d2
            ext.l   d2
            add.l   d2,a0
            rts

update_sprite:
            lea     frog_data,a0
            move.w  frog_pixel_y,d0
            move.w  frog_pixel_x,d1

            move.w  d0,d2
            lsl.w   #8,d2
            lsr.w   #1,d1
            or.b    d1,d2
            move.w  d2,(a0)

            add.w   #FROG_HEIGHT,d0
            lsl.w   #8,d0
            move.w  d0,2(a0)
            rts

;==============================================================================
; VARIABLES
;==============================================================================

frog_grid_x:    dc.w    9
frog_grid_y:    dc.w    12
frog_pixel_x:   dc.w    0
frog_pixel_y:   dc.w    0
frog_state:     dc.w    0
frog_dir:       dc.w    0
frog_anim_frame: dc.w   0
joy_prev:       dc.w    0

death_timer:    dc.w    0
flash_colour:   dc.w    0

lives:          dc.w    3
score:          dc.l    0

; Home zone state (0 = empty, 1 = filled)
home_filled:    dc.w    0,0,0,0,0

car_data:
            dc.w    0,7,1,0
            dc.w    160,7,1,0
            dc.w    100,8,-2,0
            dc.w    250,8,-2,0
            dc.w    50,9,2,0
            dc.w    200,9,2,0
            dc.w    80,10,-1,0
            dc.w    220,10,-1,0
            dc.w    30,11,3,0
            dc.w    180,11,3,0

;==============================================================================
; COPPER LIST
;==============================================================================

copperlist:
            dc.w    COLOR00
flash_copper:
            dc.w    COLOUR_BLACK

            dc.w    $0100,$1200
            dc.w    $0102,$0000
            dc.w    $0104,$0000
            dc.w    $0108,$0000
            dc.w    $010a,$0000

            dc.w    $00e0
bplpth_val: dc.w    $0000
            dc.w    $00e2
bplptl_val: dc.w    $0000

            dc.w    $0180,$0000
            dc.w    $0182,COLOUR_CAR

            ; Sprite 0-1 palette (frog and life icons share this)
            dc.w    $01a2,COLOUR_FROG
            dc.w    $01a4,COLOUR_EYES
            dc.w    $01a6,COLOUR_OUTLINE

            ; Sprite 0 pointer (main frog)
            dc.w    SPR0PTH
sprpth_val: dc.w    $0000
            dc.w    SPR0PTL
sprptl_val: dc.w    $0000

            ; Sprite 1 pointer (life icon 1)
            dc.w    SPR1PTH
spr1pth_val: dc.w   $0000
            dc.w    SPR1PTL
spr1ptl_val: dc.w   $0000

            ; Sprite 2 pointer (life icon 2)
            dc.w    SPR2PTH
spr2pth_val: dc.w   $0000
            dc.w    SPR2PTL
spr2ptl_val: dc.w   $0000

            ; Sprite 3 pointer (life icon 3)
            dc.w    $0126           ; SPR3PTH
spr3pth_val: dc.w   $0000
            dc.w    $012a           ; SPR3PTL
spr3ptl_val: dc.w   $0000

            ; Home zone row - 5 distinct zones for visual feedback
            ; Each home changes colour when filled
            dc.w    $2c07,$fffe
            dc.w    COLOR00,COLOUR_HOME     ; Gaps between homes

            ; Home 0 (columns 2-3, pixels 48+32=80 to 48+48=96)
            dc.w    $2c4f,$fffe             ; Wait for X=79
            dc.w    COLOR00
home_colour_0:
            dc.w    COLOUR_HOME_LIT

            dc.w    $2c5f,$fffe             ; Wait for X=95
            dc.w    COLOR00,COLOUR_HOME     ; Gap

            ; Home 1 (columns 6-7)
            dc.w    $2c8f,$fffe             ; Wait for X=143
            dc.w    COLOR00
home_colour_1:
            dc.w    COLOUR_HOME_LIT

            dc.w    $2c9f,$fffe             ; Wait for X=159
            dc.w    COLOR00,COLOUR_HOME     ; Gap

            ; Home 2 (columns 10-11)
            dc.w    $2ccf,$fffe             ; Wait for X=207
            dc.w    COLOR00
home_colour_2:
            dc.w    COLOUR_HOME_LIT

            dc.w    $2cdf,$fffe             ; Wait for X=223
            dc.w    COLOR00,COLOUR_HOME     ; Gap

            ; Home 3 (columns 14-15) - past X=223, need high bit
            dc.w    $2d07,$fffe             ; Wait for next pixel region
            dc.w    COLOR00
home_colour_3:
            dc.w    COLOUR_HOME_LIT

            dc.w    $2d17,$fffe
            dc.w    COLOR00,COLOUR_HOME     ; Gap

            ; Home 4 (columns 18-19)
            dc.w    $2d47,$fffe
            dc.w    COLOR00
home_colour_4:
            dc.w    COLOUR_HOME_LIT

            dc.w    $2d57,$fffe
            dc.w    COLOR00,COLOUR_HOME     ; End

            ; Rest of home row - solid colour
            dc.w    $3407,$fffe
            dc.w    COLOR00,COLOUR_HOME_LIT
            dc.w    $3807,$fffe
            dc.w    COLOR00,COLOUR_HOME

            ; Water rows
            dc.w    $3c07,$fffe
            dc.w    COLOR00,COLOUR_WATER1
            dc.w    $4c07,$fffe
            dc.w    COLOR00,COLOUR_WATER2
            dc.w    $5c07,$fffe
            dc.w    COLOR00,COLOUR_WATER1
            dc.w    $6c07,$fffe
            dc.w    COLOR00,COLOUR_WATER2
            dc.w    $7c07,$fffe
            dc.w    COLOR00,COLOUR_WATER1

            ; Median
            dc.w    $8c07,$fffe
            dc.w    COLOR00,COLOUR_MEDIAN

            ; Road rows
            dc.w    $9c07,$fffe
            dc.w    COLOR00,COLOUR_ROAD1
            dc.w    $ac07,$fffe
            dc.w    COLOR00,COLOUR_ROAD2
            dc.w    $bc07,$fffe
            dc.w    COLOR00,COLOUR_ROAD1
            dc.w    $cc07,$fffe
            dc.w    COLOR00,COLOUR_ROAD2
            dc.w    $dc07,$fffe
            dc.w    COLOR00,COLOUR_ROAD1

            ; Start zone
            dc.w    $ec07,$fffe
            dc.w    COLOR00,COLOUR_START
            dc.w    $f407,$fffe
            dc.w    COLOR00,COLOUR_START_LIT
            dc.w    $f807,$fffe
            dc.w    COLOR00,COLOUR_START

            dc.w    $fc07,$fffe
            dc.w    COLOR00,COLOUR_BLACK

            dc.w    $ffff,$fffe

;==============================================================================
; GRAPHICS DATA
;==============================================================================

            even
car_gfx:
            dc.w    $0ff0,$0ff0
            dc.w    $3ffc,$3ffc
            dc.w    $7ffe,$7ffe
            dc.w    $ffff,$ffff
            dc.w    $ffff,$ffff
            dc.w    $ffff,$ffff
            dc.w    $ffff,$ffff
            dc.w    $ffff,$ffff
            dc.w    $ffff,$ffff
            dc.w    $7ffe,$7ffe
            dc.w    $3c3c,$3c3c
            dc.w    $0000,$0000

            even
frog_data:
            dc.w    $ec50,$fc00

            dc.w    $0000,$0000
            dc.w    $07e0,$0000
            dc.w    $1ff8,$0420
            dc.w    $3ffc,$0a50
            dc.w    $7ffe,$1248
            dc.w    $7ffe,$1008
            dc.w    $ffff,$2004
            dc.w    $ffff,$0000
            dc.w    $ffff,$0000
            dc.w    $7ffe,$2004
            dc.w    $7ffe,$1008
            dc.w    $3ffc,$0810
            dc.w    $1ff8,$0420
            dc.w    $07e0,$0000
            dc.w    $0000,$0000
            dc.w    $0000,$0000

            dc.w    $0000,$0000

; Life icon sprites (small frog shape, 8 pixels tall)
            even
life_icon_1:
            dc.w    $0000,$0000
            dc.w    $0000,$0000
            dc.w    $1800,$0000
            dc.w    $3c00,$0000
            dc.w    $7e00,$0000
            dc.w    $7e00,$0000
            dc.w    $3c00,$0000
            dc.w    $1800,$0000
            dc.w    $0000,$0000
            dc.w    $0000,$0000

            even
life_icon_2:
            dc.w    $0000,$0000
            dc.w    $0000,$0000
            dc.w    $1800,$0000
            dc.w    $3c00,$0000
            dc.w    $7e00,$0000
            dc.w    $7e00,$0000
            dc.w    $3c00,$0000
            dc.w    $1800,$0000
            dc.w    $0000,$0000
            dc.w    $0000,$0000

            even
life_icon_3:
            dc.w    $0000,$0000
            dc.w    $0000,$0000
            dc.w    $1800,$0000
            dc.w    $3c00,$0000
            dc.w    $7e00,$0000
            dc.w    $7e00,$0000
            dc.w    $3c00,$0000
            dc.w    $1800,$0000
            dc.w    $0000,$0000
            dc.w    $0000,$0000

;==============================================================================
; SCREEN BUFFER
;==============================================================================

            section chipbss,bss_c

            even
screen_plane:
            ds.b    PLANE_SIZE

Build It

vasmm68k_mot -Fhunkexe -kick1hunks -o signal signal.asm

What’s Next

The game has goals and stakes, but no audio feedback. In Unit 11, we’ll add sound effects—beeps and buzzes that give the game life.

What Changed

Unit 9 → Unit 10

+327-72

1		-	`;══════════════════════════════════════════════════════════════════════════════`
	1	+	`;==============================================================================`
2	2		`; SIGNAL - A Frogger-style game for the Commodore Amiga`
3		-	`; Unit 9: Lives System`
	3	+	`; Unit 10: Home Zones`
4	4		`;`
5		-	`; Infinite respawns means no tension. This unit adds a lives system: start`
6		-	`; with 3 lives, lose one on each death, game over when empty. Small frog`
7		-	`; icons in the corner show your remaining chances.`
8		-	`;══════════════════════════════════════════════════════════════════════════════`
	5	+	`; Stakes alone aren't enough—you need a goal. This unit adds 5 home zones at`
	6	+	`; the top of the screen. Reach one, it fills in, you respawn. Fill all 5 to`
	7	+	`; complete a round. Each successful docking scores 50 points.`
	8	+	`;==============================================================================`
9	9
10		-	`;══════════════════════════════════════════════════════════════════════════════`
	10	+	`;==============================================================================`
11	11		`; CONSTANTS`
12		-	`;══════════════════════════════════════════════════════════════════════════════`
	12	+	`;==============================================================================`
13	13
14	14		`SCREEN_W equ 40`
15	15		`SCREEN_H equ 256`
			...
28	28		`STATE_IDLE equ 0`
29	29		`STATE_HOPPING equ 1`
30	30		`STATE_DYING equ 2`
31		-	`STATE_GAMEOVER equ 3 ; NEW: Game over state`
	31	+	`STATE_GAMEOVER equ 3`
32	32		`DIR_UP equ 0`
33	33		`DIR_DOWN equ 1`
34	34		`DIR_LEFT equ 2`
			...
50	50
51	51		`; Lives system`
52	52		`START_LIVES equ 3`
53		-	`LIFE_ICON_W equ 1 ; 16 pixels = 1 word`
	53	+	`LIFE_ICON_W equ 1`
54	54		`LIFE_ICON_H equ 8`
55		-	`LIFE_ICON_X equ 8 ; Left margin`
56		-	`LIFE_ICON_Y equ 260 ; Below visible area (we'll position in border)`
57		-	`LIFE_ICON_SPACING equ 20 ; Pixels between icons`
	55	+	`LIFE_ICON_X equ 8`
	56	+	`LIFE_ICON_Y equ 260`
	57	+	`LIFE_ICON_SPACING equ 20`
	58	+
	59	+	`; Home zones`
	60	+	`NUM_HOMES equ 5`
	61	+	`HOME_ROW equ 0 ; Top row of grid`
	62	+	`POINTS_PER_HOME equ 50`
	63	+
	64	+	`; Home X positions (grid coordinates): 2, 6, 10, 14, 18`
	65	+	`; Each home is 2 cells wide (even column = start of home)`
	66	+	`HOME_0_X equ 2`
	67	+	`HOME_1_X equ 6`
	68	+	`HOME_2_X equ 10`
	69	+	`HOME_3_X equ 14`
	70	+	`HOME_4_X equ 18`
58	71
59	72		`; Colours`
60	73		`COLOUR_BLACK equ $0000`
61	74		`COLOUR_HOME equ $0282`
62	75		`COLOUR_HOME_LIT equ $03a3`
	76	+	`COLOUR_HOME_FILLED equ $0f80 ; Orange for filled homes`
63	77		`COLOUR_WATER1 equ $0148`
64	78		`COLOUR_WATER2 equ $026a`
65	79		`COLOUR_MEDIAN equ $0383`
			...
71	85		`COLOUR_EYES equ $0ff0`
72	86		`COLOUR_OUTLINE equ $0000`
73	87		`COLOUR_CAR equ $0f00`
74		-	`COLOUR_LIFE equ $00f0 ; Green for life icons`
	88	+	`COLOUR_LIFE equ $00f0`
75	89
76		-	`;══════════════════════════════════════════════════════════════════════════════`
	90	+	`;==============================================================================`
77	91		`; HARDWARE REGISTERS`
78		-	`;══════════════════════════════════════════════════════════════════════════════`
	92	+	`;==============================================================================`
79	93
80	94		`CUSTOM equ $dff000`
81	95
			...
110	124		`SPR2PTH equ $128`
111	125		`SPR2PTL equ $12a`
112	126
113		-	`;══════════════════════════════════════════════════════════════════════════════`
	127	+	`;==============================================================================`
114	128		`; CODE SECTION`
115		-	`;══════════════════════════════════════════════════════════════════════════════`
	129	+	`;==============================================================================`
116	130
117	131		`section code,code_c`
118	132
			...
136	150		`move.w d0,(a1)`
137	151
138	152		`; Initialise game`
139		-	`move.w #START_LIVES,lives`
140		-	`bsr reset_frog`
	153	+	`bsr init_game`
141	154
142	155		`; Set main sprite pointer (sprite 0 = frog)`
143	156		`lea frog_data,a0`
			...
163	176		`; Enable DMA`
164	177		`move.w #$87e0,DMACON(a5)`
165	178
166		-	`;══════════════════════════════════════════════════════════════════════════════`
	179	+	`;==============================================================================`
167	180		`; MAIN LOOP`
168		-	`;══════════════════════════════════════════════════════════════════════════════`
	181	+	`;==============================================================================`
169	182
170	183		`mainloop:`
171	184		`bsr wait_vblank`
			...
184	197
185	198		`cmp.w #STATE_DYING,frog_state`
186	199		`beq.s .skip_collision`
	200	+	`cmp.w #STATE_IDLE,frog_state`
	201	+	`bne.s .skip_collision`
	202	+	`bsr check_home`
187	203		`bsr check_collision`
188	204		`.skip_collision:`
189	205
			...
191	207
192	208		`.game_over_loop:`
193	209		`; Game over - wait for fire button to restart`
194		-	`btst #7,$bfe001 ; Check fire button (active low)`
195		-	`bne.s mainloop ; Not pressed, keep waiting`
	210	+	`btst #7,$bfe001`
	211	+	`bne.s mainloop`
196	212
197	213		`; Restart game`
198		-	`move.w #START_LIVES,lives`
199		-	`bsr reset_frog`
	214	+	`bsr init_game`
200	215		`bsr update_life_display`
201	216		`bsr clear_screen`
202	217
203	218		`bra mainloop`
204	219
205		-	`;══════════════════════════════════════════════════════════════════════════════`
206		-	`; LIFE DISPLAY`
207		-	`;══════════════════════════════════════════════════════════════════════════════`
	220	+	`;==============================================================================`
	221	+	`; GAME INITIALISATION`
	222	+	`;==============================================================================`
	223	+
	224	+	`init_game:`
	225	+	`move.w #START_LIVES,lives`
	226	+	`clr.l score`
	227	+
	228	+	`; Clear all homes`
	229	+	`lea home_filled,a0`
	230	+	`moveq #NUM_HOMES-1,d0`
	231	+	`.clear_homes:`
	232	+	`clr.w (a0)+`
	233	+	`dbf d0,.clear_homes`
	234	+
	235	+	`bsr update_home_display`
	236	+	`bsr reset_frog`
	237	+	`rts`
	238	+
	239	+	`;==============================================================================`
	240	+	`; HOME ZONE DETECTION`
	241	+	`;==============================================================================`
208	242
209	243		`;------------------------------------------------------------------------------`
210		-	`; SETUP_LIFE_SPRITES - Set sprite pointers for life icons`
	244	+	`; CHECK_HOME - Check if frog has reached a home zone`
	245	+	`;------------------------------------------------------------------------------`
	246	+	`check_home:`
	247	+	`; Only check if at top row`
	248	+	`move.w frog_grid_y,d0`
	249	+	`tst.w d0`
	250	+	`bne .not_home`
	251	+
	252	+	`; At top row - determine which home`
	253	+	`move.w frog_grid_x,d0`
	254	+
	255	+	`; Check home 0 (X = 2-3)`
	256	+	`cmp.w #HOME_0_X,d0`
	257	+	`blt.s .not_home`
	258	+	`cmp.w #HOME_0_X+2,d0`
	259	+	`blt.s .home_0`
	260	+
	261	+	`; Check home 1 (X = 6-7)`
	262	+	`cmp.w #HOME_1_X,d0`
	263	+	`blt.s .not_home`
	264	+	`cmp.w #HOME_1_X+2,d0`
	265	+	`blt.s .home_1`
	266	+
	267	+	`; Check home 2 (X = 10-11)`
	268	+	`cmp.w #HOME_2_X,d0`
	269	+	`blt.s .not_home`
	270	+	`cmp.w #HOME_2_X+2,d0`
	271	+	`blt.s .home_2`
	272	+
	273	+	`; Check home 3 (X = 14-15)`
	274	+	`cmp.w #HOME_3_X,d0`
	275	+	`blt.s .not_home`
	276	+	`cmp.w #HOME_3_X+2,d0`
	277	+	`blt.s .home_3`
	278	+
	279	+	`; Check home 4 (X = 18-19)`
	280	+	`cmp.w #HOME_4_X,d0`
	281	+	`blt.s .not_home`
	282	+	`cmp.w #HOME_4_X+2,d0`
	283	+	`blt.s .home_4`
	284	+
	285	+	`; Between homes - death!`
	286	+	`bra .death_between`
	287	+
	288	+	`.home_0: moveq #0,d1`
	289	+	`bra.s .check_filled`
	290	+	`.home_1: moveq #1,d1`
	291	+	`bra.s .check_filled`
	292	+	`.home_2: moveq #2,d1`
	293	+	`bra.s .check_filled`
	294	+	`.home_3: moveq #3,d1`
	295	+	`bra.s .check_filled`
	296	+	`.home_4: moveq #4,d1`
	297	+
	298	+	`.check_filled:`
	299	+	`; D1 = home index (0-4)`
	300	+	`lea home_filled,a0`
	301	+	`add.w d1,d1 ; *2 for word offset`
	302	+	`tst.w 0(a0,d1.w)`
	303	+	`bne.s .death_filled ; Already filled - death!`
	304	+
	305	+	`; Home is empty - fill it!`
	306	+	`move.w #1,0(a0,d1.w)`
	307	+
	308	+	`; Add points`
	309	+	`add.l #POINTS_PER_HOME,score`
	310	+
	311	+	`; Update display`
	312	+	`bsr update_home_display`
	313	+
	314	+	`; Check if all homes filled`
	315	+	`bsr check_round_complete`
	316	+
	317	+	`; Respawn frog`
	318	+	`bsr reset_frog`
	319	+	`rts`
	320	+
	321	+	`.death_filled:`
	322	+	`; Landed on filled home - death`
	323	+	`bsr trigger_death`
	324	+	`rts`
	325	+
	326	+	`.death_between:`
	327	+	`; Landed between homes (on lily pad gaps) - death`
	328	+	`bsr trigger_death`
	329	+	`rts`
	330	+
	331	+	`.not_home:`
	332	+	`rts`
	333	+
	334	+	`;------------------------------------------------------------------------------`
	335	+	`; CHECK_ROUND_COMPLETE - Check if all 5 homes are filled`
	336	+	`;------------------------------------------------------------------------------`
	337	+	`check_round_complete:`
	338	+	`lea home_filled,a0`
	339	+	`moveq #NUM_HOMES-1,d0`
	340	+	`moveq #0,d1 ; Count filled homes`
	341	+
	342	+	`.loop:`
	343	+	`tst.w (a0)+`
	344	+	`beq.s .not_complete`
	345	+	`addq.w #1,d1`
	346	+	`dbf d0,.loop`
	347	+
	348	+	`; All homes filled - reset for next round`
	349	+	`cmp.w #NUM_HOMES,d1`
	350	+	`bne.s .not_complete`
	351	+
	352	+	`; Clear all homes for next round`
	353	+	`lea home_filled,a0`
	354	+	`moveq #NUM_HOMES-1,d0`
	355	+	`.clear:`
	356	+	`clr.w (a0)+`
	357	+	`dbf d0,.clear`
	358	+
	359	+	`bsr update_home_display`
	360	+	`; Could add bonus points here, increase speed, etc.`
	361	+
	362	+	`.not_complete:`
	363	+	`rts`
	364	+
	365	+	`;------------------------------------------------------------------------------`
	366	+	`; UPDATE_HOME_DISPLAY - Update Copper colours to show filled homes`
211	367		`;------------------------------------------------------------------------------`
	368	+	`update_home_display:`
	369	+	`lea home_filled,a0`
	370	+	`lea home_colour_0,a1`
	371	+
	372	+	`; Home 0`
	373	+	`tst.w (a0)+`
	374	+	`beq.s .home0_empty`
	375	+	`move.w #COLOUR_HOME_FILLED,(a1)`
	376	+	`bra.s .home1`
	377	+	`.home0_empty:`
	378	+	`move.w #COLOUR_HOME_LIT,(a1)`
	379	+
	380	+	`.home1:`
	381	+	`lea home_colour_1,a1`
	382	+	`tst.w (a0)+`
	383	+	`beq.s .home1_empty`
	384	+	`move.w #COLOUR_HOME_FILLED,(a1)`
	385	+	`bra.s .home2`
	386	+	`.home1_empty:`
	387	+	`move.w #COLOUR_HOME_LIT,(a1)`
	388	+
	389	+	`.home2:`
	390	+	`lea home_colour_2,a1`
	391	+	`tst.w (a0)+`
	392	+	`beq.s .home2_empty`
	393	+	`move.w #COLOUR_HOME_FILLED,(a1)`
	394	+	`bra.s .home3`
	395	+	`.home2_empty:`
	396	+	`move.w #COLOUR_HOME_LIT,(a1)`
	397	+
	398	+	`.home3:`
	399	+	`lea home_colour_3,a1`
	400	+	`tst.w (a0)+`
	401	+	`beq.s .home3_empty`
	402	+	`move.w #COLOUR_HOME_FILLED,(a1)`
	403	+	`bra.s .home4`
	404	+	`.home3_empty:`
	405	+	`move.w #COLOUR_HOME_LIT,(a1)`
	406	+
	407	+	`.home4:`
	408	+	`lea home_colour_4,a1`
	409	+	`tst.w (a0)+`
	410	+	`beq.s .home4_empty`
	411	+	`move.w #COLOUR_HOME_FILLED,(a1)`
	412	+	`rts`
	413	+	`.home4_empty:`
	414	+	`move.w #COLOUR_HOME_LIT,(a1)`
	415	+	`rts`
	416	+
	417	+	`;==============================================================================`
	418	+	`; LIFE DISPLAY`
	419	+	`;==============================================================================`
	420	+
212	421		`setup_life_sprites:`
213	422		`; Sprite 1`
214	423		`lea life_icon_1,a0`
			...
242	451
243	452		`rts`
244	453
245		-	`;------------------------------------------------------------------------------`
246		-	`; UPDATE_LIFE_DISPLAY - Show/hide life icons based on lives count`
247		-	`;------------------------------------------------------------------------------`
248	454		`update_life_display:`
249		-	`; Position life icons at top of screen`
250		-	`; VSTART = 30, VSTOP = 38 (8 pixels tall)`
251		-	`; HSTART varies: 64, 80, 96 (sprite coords)`
252		-
253	455		`; Life 1 (always show if lives >= 1)`
254	456		`lea life_icon_1,a0`
255	457		`move.w lives,d0`
256	458		`cmp.w #1,d0`
257	459		`blt.s .hide_life1`
258		-	`move.w #$1e20,$0(a0) ; VSTART=30, HSTART=64`
259		-	`move.w #$2600,$2(a0) ; VSTOP=38`
	460	+	`move.w #$1e20,$0(a0)`
	461	+	`move.w #$2600,$2(a0)`
260	462		`bra.s .life2`
261	463		`.hide_life1:`
262		-	`clr.l (a0) ; Hide sprite`
	464	+	`clr.l (a0)`
263	465
264	466		`.life2:`
265	467		`lea life_icon_2,a0`
266	468		`cmp.w #2,d0`
267	469		`blt.s .hide_life2`
268		-	`move.w #$1e28,$0(a0) ; VSTART=30, HSTART=80`
	470	+	`move.w #$1e28,$0(a0)`
269	471		`move.w #$2600,$2(a0)`
270	472		`bra.s .life3`
271	473		`.hide_life2:`
			...
275	477		`lea life_icon_3,a0`
276	478		`cmp.w #3,d0`
277	479		`blt.s .hide_life3`
278		-	`move.w #$1e30,$0(a0) ; VSTART=30, HSTART=96`
	480	+	`move.w #$1e30,$0(a0)`
279	481		`move.w #$2600,$2(a0)`
280	482		`rts`
281	483		`.hide_life3:`
282	484		`clr.l (a0)`
283	485		`rts`
284	486
285		-	`;══════════════════════════════════════════════════════════════════════════════`
	487	+	`;==============================================================================`
286	488		`; COLLISION AND DEATH`
287		-	`;══════════════════════════════════════════════════════════════════════════════`
	489	+	`;==============================================================================`
288	490
289	491		`check_collision:`
290	492		`move.w frog_grid_y,d0`
			...
335	537
336	538		`rts`
337	539
338		-	`;------------------------------------------------------------------------------`
339		-	`; RESET_FROG - Reset frog position (called on respawn and game start)`
340		-	`;------------------------------------------------------------------------------`
341	540		`reset_frog:`
342	541		`move.w #START_GRID_X,frog_grid_x`
343	542		`move.w #START_GRID_Y,frog_grid_y`
			...
348	547		`bsr grid_to_pixels`
349	548		`rts`
350	549
351		-	`;══════════════════════════════════════════════════════════════════════════════`
	550	+	`;==============================================================================`
352	551		`; CAR MANAGEMENT`
353		-	`;══════════════════════════════════════════════════════════════════════════════`
	552	+	`;==============================================================================`
354	553
355	554		`erase_all_cars:`
356	555		`lea car_data,a2`
			...
428	627		`dbf d7,.loop`
429	628		`rts`
430	629
431		-	`;══════════════════════════════════════════════════════════════════════════════`
	630	+	`;==============================================================================`
432	631		`; FROG ROUTINES`
433		-	`;══════════════════════════════════════════════════════════════════════════════`
	632	+	`;==============================================================================`
434	633
435	634		`update_frog:`
436	635		`move.w frog_state,d0`
			...
559	758		`move.w flash_colour,flash_copper`
560	759		`rts`
561	760
562		-	`;══════════════════════════════════════════════════════════════════════════════`
	761	+	`;==============================================================================`
563	762		`; UTILITY ROUTINES`
564		-	`;══════════════════════════════════════════════════════════════════════════════`
	763	+	`;==============================================================================`
565	764
566	765		`grid_to_pixels:`
567	766		`move.w frog_grid_x,d0`
			...
640	839		`move.w d0,2(a0)`
641	840		`rts`
642	841
643		-	`;══════════════════════════════════════════════════════════════════════════════`
	842	+	`;==============================================================================`
644	843		`; VARIABLES`
645		-	`;══════════════════════════════════════════════════════════════════════════════`
	844	+	`;==============================================================================`
646	845
647	846		`frog_grid_x: dc.w 9`
648	847		`frog_grid_y: dc.w 12`
			...
657	856		`flash_colour: dc.w 0`
658	857
659	858		`lives: dc.w 3`
	859	+	`score: dc.l 0`
	860	+
	861	+	`; Home zone state (0 = empty, 1 = filled)`
	862	+	`home_filled: dc.w 0,0,0,0,0`
660	863
661	864		`car_data:`
662	865		`dc.w 0,7,1,0`
			...
670	873		`dc.w 30,11,3,0`
671	874		`dc.w 180,11,3,0`
672	875
673		-	`;══════════════════════════════════════════════════════════════════════════════`
	876	+	`;==============================================================================`
674	877		`; COPPER LIST`
675		-	`;══════════════════════════════════════════════════════════════════════════════`
	878	+	`;==============================================================================`
676	879
677	880		`copperlist:`
678	881		`dc.w COLOR00`
			...
719	922		`; Sprite 3 pointer (life icon 3)`
720	923		`dc.w $0126 ; SPR3PTH`
721	924		`spr3pth_val: dc.w $0000`
722		-	`dc.w $0128 ; SPR3PTL (note: this is wrong, should be $012a)`
	925	+	`dc.w $012a ; SPR3PTL`
723	926		`spr3ptl_val: dc.w $0000`
724	927
725		-	`; Zone colours`
	928	+	`; Home zone row - 5 distinct zones for visual feedback`
	929	+	`; Each home changes colour when filled`
726	930		`dc.w $2c07,$fffe`
727		-	`dc.w COLOR00,COLOUR_HOME`
	931	+	`dc.w COLOR00,COLOUR_HOME ; Gaps between homes`
	932	+
	933	+	`; Home 0 (columns 2-3, pixels 48+32=80 to 48+48=96)`
	934	+	`dc.w $2c4f,$fffe ; Wait for X=79`
	935	+	`dc.w COLOR00`
	936	+	`home_colour_0:`
	937	+	`dc.w COLOUR_HOME_LIT`
	938	+
	939	+	`dc.w $2c5f,$fffe ; Wait for X=95`
	940	+	`dc.w COLOR00,COLOUR_HOME ; Gap`
	941	+
	942	+	`; Home 1 (columns 6-7)`
	943	+	`dc.w $2c8f,$fffe ; Wait for X=143`
	944	+	`dc.w COLOR00`
	945	+	`home_colour_1:`
	946	+	`dc.w COLOUR_HOME_LIT`
	947	+
	948	+	`dc.w $2c9f,$fffe ; Wait for X=159`
	949	+	`dc.w COLOR00,COLOUR_HOME ; Gap`
	950	+
	951	+	`; Home 2 (columns 10-11)`
	952	+	`dc.w $2ccf,$fffe ; Wait for X=207`
	953	+	`dc.w COLOR00`
	954	+	`home_colour_2:`
	955	+	`dc.w COLOUR_HOME_LIT`
	956	+
	957	+	`dc.w $2cdf,$fffe ; Wait for X=223`
	958	+	`dc.w COLOR00,COLOUR_HOME ; Gap`
	959	+
	960	+	`; Home 3 (columns 14-15) - past X=223, need high bit`
	961	+	`dc.w $2d07,$fffe ; Wait for next pixel region`
	962	+	`dc.w COLOR00`
	963	+	`home_colour_3:`
	964	+	`dc.w COLOUR_HOME_LIT`
	965	+
	966	+	`dc.w $2d17,$fffe`
	967	+	`dc.w COLOR00,COLOUR_HOME ; Gap`
	968	+
	969	+	`; Home 4 (columns 18-19)`
	970	+	`dc.w $2d47,$fffe`
	971	+	`dc.w COLOR00`
	972	+	`home_colour_4:`
	973	+	`dc.w COLOUR_HOME_LIT`
	974	+
	975	+	`dc.w $2d57,$fffe`
	976	+	`dc.w COLOR00,COLOUR_HOME ; End`
	977	+
	978	+	`; Rest of home row - solid colour`
728	979		`dc.w $3407,$fffe`
729	980		`dc.w COLOR00,COLOUR_HOME_LIT`
730	981		`dc.w $3807,$fffe`
731	982		`dc.w COLOR00,COLOUR_HOME`
732	983
	984	+	`; Water rows`
733	985		`dc.w $3c07,$fffe`
734	986		`dc.w COLOR00,COLOUR_WATER1`
735	987		`dc.w $4c07,$fffe`
			...
741	993		`dc.w $7c07,$fffe`
742	994		`dc.w COLOR00,COLOUR_WATER1`
743	995
	996	+	`; Median`
744	997		`dc.w $8c07,$fffe`
745	998		`dc.w COLOR00,COLOUR_MEDIAN`
746	999
	1000	+	`; Road rows`
747	1001		`dc.w $9c07,$fffe`
748	1002		`dc.w COLOR00,COLOUR_ROAD1`
749	1003		`dc.w $ac07,$fffe`
			...
755	1009		`dc.w $dc07,$fffe`
756	1010		`dc.w COLOR00,COLOUR_ROAD1`
757	1011
	1012	+	`; Start zone`
758	1013		`dc.w $ec07,$fffe`
759	1014		`dc.w COLOR00,COLOUR_START`
760	1015		`dc.w $f407,$fffe`
			...
767	1022
768	1023		`dc.w $ffff,$fffe`
769	1024
770		-	`;══════════════════════════════════════════════════════════════════════════════`
	1025	+	`;==============================================================================`
771	1026		`; GRAPHICS DATA`
772		-	`;══════════════════════════════════════════════════════════════════════════════`
	1027	+	`;==============================================================================`
773	1028
774	1029		`even`
775	1030		`car_gfx:`
			...
812	1067		`; Life icon sprites (small frog shape, 8 pixels tall)`
813	1068		`even`
814	1069		`life_icon_1:`
815		-	`dc.w $0000,$0000 ; Control words (set by code)`
816	1070		`dc.w $0000,$0000`
817		-	`dc.w $1800,$0000 ; ..##............`
818		-	`dc.w $3c00,$0000 ; .####...........`
819		-	`dc.w $7e00,$0000 ; .######.........`
820		-	`dc.w $7e00,$0000 ; .######.........`
821		-	`dc.w $3c00,$0000 ; .####...........`
822		-	`dc.w $1800,$0000 ; ..##............`
823	1071		`dc.w $0000,$0000`
824		-	`dc.w $0000,$0000 ; End marker`
	1072	+	`dc.w $1800,$0000`
	1073	+	`dc.w $3c00,$0000`
	1074	+	`dc.w $7e00,$0000`
	1075	+	`dc.w $7e00,$0000`
	1076	+	`dc.w $3c00,$0000`
	1077	+	`dc.w $1800,$0000`
	1078	+	`dc.w $0000,$0000`
	1079	+	`dc.w $0000,$0000`
825	1080
826	1081		`even`
827	1082		`life_icon_2:`
			...
849	1104		`dc.w $0000,$0000`
850	1105		`dc.w $0000,$0000`
851	1106
852		-	`;══════════════════════════════════════════════════════════════════════════════`
	1107	+	`;==============================================================================`
853	1108		`; SCREEN BUFFER`
854		-	`;══════════════════════════════════════════════════════════════════════════════`
	1109	+	`;==============================================================================`
855	1110
856	1111		`section chipbss,bss_c`
857	1112