Game 1 Unit 12 of 64 1 hr learning time
Score Display
Binary to decimal. Blitter draws digits. Player sees progress. Visual feedback.
19% of Signal
What You’re Building
Visual feedback.
Tracking points internally is useless if players can’t see them. This unit adds score display using bitmap digits. We convert the binary score to decimal and draw each digit using the Blitter.
By the end of this unit:
- 6-digit score displayed on screen
- Binary to decimal conversion using DIVU
- Bitmap digit font (0-9)
- Blitter draws digits from font data
The Digit Font
We define a simple 8x8 pixel bitmap font for digits 0-9. Each digit is stored as 8 words (16 bytes), with the pattern in the high byte:
; Digit Font Data
; 8x8 pixel digits 0-9, 16 bytes each (8 words)
even
digit_font:
; 0 - rounded rectangle with diagonal line
dc.w $3c00 ; ..####..
dc.w $6600 ; .##..##.
dc.w $6e00 ; .##.###.
dc.w $7e00 ; .######.
dc.w $7600 ; .###.##.
dc.w $6600 ; .##..##.
dc.w $3c00 ; ..####..
dc.w $0000
; 1 - simple vertical line with base
dc.w $1800 ; ...##...
dc.w $3800 ; ..###...
dc.w $1800 ; ...##...
dc.w $1800 ; ...##...
dc.w $1800 ; ...##...
dc.w $1800 ; ...##...
dc.w $7e00 ; .######.
dc.w $0000
; 2 - curves down then horizontal
dc.w $3c00 ; ..####..
dc.w $6600 ; .##..##.
dc.w $0600 ; .....##.
dc.w $1c00 ; ...###..
dc.w $3000 ; ..##....
dc.w $6000 ; .##.....
dc.w $7e00 ; .######.
dc.w $0000
; 3 - two bumps right side
dc.w $3c00 ; ..####..
dc.w $6600 ; .##..##.
dc.w $0600 ; .....##.
dc.w $1c00 ; ...###..
dc.w $0600 ; .....##.
dc.w $6600 ; .##..##.
dc.w $3c00 ; ..####..
dc.w $0000
; 4 - vertical meets horizontal
dc.w $0c00 ; ....##..
dc.w $1c00 ; ...###..
dc.w $3c00 ; ..####..
dc.w $6c00 ; .##.##..
dc.w $7e00 ; .######.
dc.w $0c00 ; ....##..
dc.w $0c00 ; ....##..
dc.w $0000
; 5 - horizontal then curve
dc.w $7e00 ; .######.
dc.w $6000 ; .##.....
dc.w $7c00 ; .#####..
dc.w $0600 ; .....##.
dc.w $0600 ; .....##.
dc.w $6600 ; .##..##.
dc.w $3c00 ; ..####..
dc.w $0000
; 6 - curve with internal loop
dc.w $1c00 ; ...###..
dc.w $3000 ; ..##....
dc.w $6000 ; .##.....
dc.w $7c00 ; .#####..
dc.w $6600 ; .##..##.
dc.w $6600 ; .##..##.
dc.w $3c00 ; ..####..
dc.w $0000
; 7 - diagonal from top
dc.w $7e00 ; .######.
dc.w $0600 ; .....##.
dc.w $0c00 ; ....##..
dc.w $1800 ; ...##...
dc.w $3000 ; ..##....
dc.w $3000 ; ..##....
dc.w $3000 ; ..##....
dc.w $0000
; 8 - two loops stacked
dc.w $3c00 ; ..####..
dc.w $6600 ; .##..##.
dc.w $6600 ; .##..##.
dc.w $3c00 ; ..####..
dc.w $6600 ; .##..##.
dc.w $6600 ; .##..##.
dc.w $3c00 ; ..####..
dc.w $0000
; 9 - loop with tail
dc.w $3c00 ; ..####..
dc.w $6600 ; .##..##.
dc.w $6600 ; .##..##.
dc.w $3e00 ; ..#####.
dc.w $0600 ; .....##.
dc.w $0c00 ; ....##..
dc.w $3800 ; ..###...
dc.w $0000
The word format ensures proper alignment for the Blitter. The low byte is always zero, so the visible digit occupies the left 8 pixels of each 16-pixel word.
Binary to Decimal Conversion
The score is a 32-bit binary number. To display it, we convert to 6 decimal digits using repeated division by 10:
; Binary to Decimal Conversion
; Convert 32-bit score to 6 individual digits
display_score:
movem.l d0-d4/a0-a3,-(sp)
; Convert score to 6 decimal digits
move.l score(pc),d0 ; Load score (PC-relative)
; Work backwards: divide by 10 repeatedly
lea score_digits+12,a0 ; Point past end of buffer
moveq #5,d4 ; 6 digits (0-5)
.convert:
; DIVU divides D0 by 10
; Result: D0.W = quotient, D0 high word = remainder
divu #10,d0 ; d0 = quotient:remainder
swap d0 ; Get remainder in low word
move.w d0,-(a0) ; Store digit (0-9)
clr.w d0 ; Clear remainder
swap d0 ; Quotient back in low word
dbf d4,.convert
; score_digits now contains 6 digit values (0-9)
; Draw each digit using font lookup...
; (drawing code follows)
movem.l (sp)+,d0-d4/a0-a3
rts
The DIVU instruction divides a 32-bit dividend by a 16-bit divisor:
- Low word of result = quotient
- High word of result = remainder
We extract digits from right to left (ones place first), storing them in reverse order so the array reads left to right.
Drawing Digits with the Blitter
Each digit is drawn by blitting from the font data to the screen:
.draw_loop:
move.w (a1)+,d0 ; Get digit value (0-9)
mulu #16,d0 ; Offset into font (16 bytes/digit)
lea digit_font,a0
add.l d0,a0 ; Point to correct digit
bsr wait_blit
move.l a0,BLTAPTH(a5) ; Source: font data
move.l a2,BLTDPTH(a5) ; Dest: screen position
move.w #$ffff,BLTAFWM(a5)
move.w #$ffff,BLTALWM(a5)
move.w #0,BLTAMOD(a5)
move.w #SCREEN_W-2,BLTDMOD(a5)
move.w #$09f0,BLTCON0(a5) ; D = A (copy)
move.w #0,BLTCON1(a5)
move.w #(8<<6)|1,BLTSIZE(a5) ; 8 rows, 1 word
addq.l #2,a2 ; Next digit position
dbf d4,.draw_loopKey points:
- Each digit is 1 word (16 pixels) wide, but only the left 8 pixels contain the pattern
- We advance by 2 bytes between digits for word alignment
- BLTCON0 = $09f0 means: use channel A, use channel D, minterm = copy A to D
Word Alignment
The Blitter works with word-aligned addresses. When positioning digits:
SCORE_X equ 240 ; Pixel X position
SCORE_Y equ 200 ; Pixel Y position
; Calculate screen address
lea screen_plane,a2
add.l #SCORE_Y*SCREEN_W+SCORE_X/8,a2We divide X by 8 to convert pixels to bytes. The destination must be word-aligned, so we advance by 2 bytes (16 pixels) between digits rather than 1 byte.
DIVU Limitations
DIVU produces a 16-bit quotient. If the score exceeds 655,359 (quotient > 65535), the division overflows. For a 6-digit display (max 999,999), this limits practical scores.
For larger scores, you’d need software division routines. For our Frogger clone, this limit is more than sufficient.
When to Update
We call display_score at strategic points:
- Game start: Show initial 000000
- Home reached: Update after adding points
- Game restart: Reset display after game over
; After adding points for reaching home
add.l #POINTS_PER_HOME,score
bsr display_score ; Update displayKey Takeaways
- DIVU extracts decimal digits via remainder
- Bitmap fonts are simple arrays of pixel data
- Blitter copies font data to screen efficiently
- Word alignment required for Blitter destinations
- Immediate feedback makes scoring meaningful
The Code
;==============================================================================
; SIGNAL - A Frogger-style game for the Commodore Amiga
; Unit 12: Score Display
;
; Tracking points internally is useless if players can't see them. This unit
; adds score display using bitmap digits. We convert the binary score to
; decimal and draw each digit using the Blitter.
;==============================================================================
;==============================================================================
; 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
START_LIVES equ 3
NUM_HOMES equ 5
HOME_ROW equ 0
POINTS_PER_HOME equ 50
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
; Score display - position in start zone (below cars)
SCORE_X equ 256 ; Pixel X position (must be byte-aligned)
SCORE_Y equ 236 ; Pixel Y position (grid row 12, in start zone)
DIGIT_H equ 8 ; 8 pixels tall
NUM_DIGITS equ 6 ; Display 6 digits (up to 999,999)
; Audio constants
SND_HOP equ 0
SND_DEATH equ 1
SND_HOME equ 2
; Colours
COLOUR_BLACK equ $0000
COLOUR_HOME equ $0282
COLOUR_HOME_LIT equ $03a3
COLOUR_HOME_FILLED equ $0f80
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
;==============================================================================
; 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
BLTADAT equ $074
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
AUD0LC equ $0a0
AUD0LEN equ $0a4
AUD0PER equ $0a6
AUD0VOL equ $0a8
;==============================================================================
; 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)
; Enable Blitter DMA for screen clearing and drawing
move.w #$8040,DMACON(a5) ; BLTDMA on
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
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)
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)
move.w #$87e1,DMACON(a5)
; Display score after all DMA enabled
bsr display_score
;==============================================================================
; MAIN LOOP
;==============================================================================
mainloop:
bsr wait_vblank
cmp.w #STATE_GAMEOVER,frog_state
beq .game_over_loop
bsr update_frog
bsr update_sprite
bsr erase_all_cars
bsr move_all_cars
bsr draw_all_cars
cmp.w #STATE_DYING,frog_state
beq.s .skip_collision
cmp.w #STATE_IDLE,frog_state
bne.s .skip_collision
bsr check_home
bsr check_collision
.skip_collision:
bra mainloop
.game_over_loop:
btst #7,$bfe001
bne.s mainloop
bsr init_game
bsr update_life_display
bsr display_score
bsr clear_screen
bra mainloop
;==============================================================================
; SCORE DISPLAY
;==============================================================================
;------------------------------------------------------------------------------
; DISPLAY_SCORE - Convert score to digits and display
; Simplified: just draws "000000" for now
;------------------------------------------------------------------------------
display_score:
movem.l d0-d4/a0-a3,-(sp)
; Convert score to 6 decimal digits
move.l score(pc),d0 ; Use PC-relative addressing
lea score_digits+12,a0 ; Point past end of buffer
moveq #5,d4
.convert:
divu #10,d0 ; d0 low = quotient, d0 high = remainder
swap d0
move.w d0,-(a0) ; Store remainder
clr.w d0
swap d0
dbf d4,.convert
; Draw 6 digits using CPU byte copies (tight 8-pixel spacing)
lea score_digits,a1 ; Digit values
lea screen_plane,a2
add.l #SCORE_Y*SCREEN_W+SCORE_X/8,a2 ; Base destination
moveq #5,d4 ; 6 digits
.draw_digit:
move.w (a1)+,d0 ; Get digit value (0-9)
lsl.w #4,d0 ; *16: each digit = 16 bytes
lea digit_font,a0
add.w d0,a0 ; Point to correct digit
; Copy 8 rows, 1 byte each (CPU, no alignment issues)
move.l a2,a3 ; Dest for this digit
moveq #7,d3 ; 8 rows
.copy_row:
move.b (a0),(a3) ; Copy high byte of word
addq.l #2,a0 ; Next source word
lea SCREEN_W(a3),a3 ; Next dest row
dbf d3,.copy_row
addq.l #1,a2 ; Move right by 1 byte (8 pixels)
dbf d4,.draw_digit
movem.l (sp)+,d0-d4/a0-a3
rts
;------------------------------------------------------------------------------
; CALC_PIXEL_ADDR - Calculate screen address for pixel coordinates
; Input: D0 = X, D1 = Y
; Output: A2 = screen address
;------------------------------------------------------------------------------
calc_pixel_addr:
lea screen_plane,a2
move.w d1,d2
mulu #SCREEN_W,d2
add.l d2,a2
move.w d0,d2
lsr.w #3,d2
ext.l d2
add.l d2,a2
rts
;==============================================================================
; SOUND ROUTINES
;==============================================================================
play_sound:
cmp.w #SND_HOP,d0
beq.s .play_hop
cmp.w #SND_DEATH,d0
beq.s .play_death
cmp.w #SND_HOME,d0
beq.s .play_home
rts
.play_hop:
lea sound_hop,a0
move.w #HOP_LEN/2,d1
move.w #300,d2
bra.s .do_play
.play_death:
lea sound_death,a0
move.w #DEATH_LEN/2,d1
move.w #500,d2
bra.s .do_play
.play_home:
lea sound_home,a0
move.w #HOME_LEN/2,d1
move.w #200,d2
.do_play:
move.w #$0001,DMACON(a5)
move.l a0,AUD0LC(a5)
move.w d1,AUD0LEN(a5)
move.w d2,AUD0PER(a5)
move.w #64,AUD0VOL(a5)
move.w #$8001,DMACON(a5)
rts
;==============================================================================
; GAME INITIALISATION
;==============================================================================
init_game:
move.w #START_LIVES,lives
clr.l score
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:
move.w frog_grid_y,d0
tst.w d0
bne .not_home
move.w frog_grid_x,d0
cmp.w #HOME_0_X,d0
blt .not_home
cmp.w #HOME_0_X+2,d0
blt.s .home_0
cmp.w #HOME_1_X,d0
blt .not_home
cmp.w #HOME_1_X+2,d0
blt.s .home_1
cmp.w #HOME_2_X,d0
blt .not_home
cmp.w #HOME_2_X+2,d0
blt.s .home_2
cmp.w #HOME_3_X,d0
blt .not_home
cmp.w #HOME_3_X+2,d0
blt.s .home_3
cmp.w #HOME_4_X,d0
blt .not_home
cmp.w #HOME_4_X+2,d0
blt.s .home_4
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:
lea home_filled,a0
add.w d1,d1
tst.w 0(a0,d1.w)
bne.s .death_filled
move.w #1,0(a0,d1.w)
add.l #POINTS_PER_HOME,score
move.w #SND_HOME,d0
bsr play_sound
bsr update_home_display
bsr display_score ; Update score display
bsr check_round_complete
bsr reset_frog
rts
.death_filled:
.death_between:
bsr trigger_death
rts
.not_home:
rts
check_round_complete:
lea home_filled,a0
moveq #NUM_HOMES-1,d0
moveq #0,d1
.loop:
tst.w (a0)+
beq.s .not_complete
addq.w #1,d1
dbf d0,.loop
cmp.w #NUM_HOMES,d1
bne.s .not_complete
lea home_filled,a0
moveq #NUM_HOMES-1,d0
.clear:
clr.w (a0)+
dbf d0,.clear
bsr update_home_display
.not_complete:
rts
update_home_display:
lea home_filled,a0
lea home_colour_0,a1
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:
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)
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)
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:
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
move.w #SND_DEATH,d0
bsr play_sound
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
tst.w lives
beq.s .game_over
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
move.w #SND_HOP,d0
bsr play_sound
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_filled: dc.w 0,0,0,0,0
; Buffer for score digits
score_digits: dc.w 0,0,0,0,0,0
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
dc.w $01a2,COLOUR_FROG
dc.w $01a4,COLOUR_EYES
dc.w $01a6,COLOUR_OUTLINE
dc.w SPR0PTH
sprpth_val: dc.w $0000
dc.w SPR0PTL
sprptl_val: dc.w $0000
dc.w SPR1PTH
spr1pth_val: dc.w $0000
dc.w SPR1PTL
spr1ptl_val: dc.w $0000
dc.w SPR2PTH
spr2pth_val: dc.w $0000
dc.w SPR2PTL
spr2ptl_val: dc.w $0000
dc.w $0126
spr3pth_val: dc.w $0000
dc.w $012a
spr3ptl_val: dc.w $0000
; Home zone row
dc.w $2c07,$fffe
dc.w COLOR00,COLOUR_HOME
dc.w $2c4f,$fffe
dc.w COLOR00
home_colour_0:
dc.w COLOUR_HOME_LIT
dc.w $2c5f,$fffe
dc.w COLOR00,COLOUR_HOME
dc.w $2c8f,$fffe
dc.w COLOR00
home_colour_1:
dc.w COLOUR_HOME_LIT
dc.w $2c9f,$fffe
dc.w COLOR00,COLOUR_HOME
dc.w $2ccf,$fffe
dc.w COLOR00
home_colour_2:
dc.w COLOUR_HOME_LIT
dc.w $2cdf,$fffe
dc.w COLOR00,COLOUR_HOME
dc.w $2d07,$fffe
dc.w COLOR00
home_colour_3:
dc.w COLOUR_HOME_LIT
dc.w $2d17,$fffe
dc.w COLOR00,COLOUR_HOME
dc.w $2d47,$fffe
dc.w COLOR00
home_colour_4:
dc.w COLOUR_HOME_LIT
dc.w $2d57,$fffe
dc.w COLOR00,COLOUR_HOME
dc.w $3407,$fffe
dc.w COLOR00,COLOUR_HOME_LIT
dc.w $3807,$fffe
dc.w COLOR00,COLOUR_HOME
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
dc.w $8c07,$fffe
dc.w COLOR00,COLOUR_MEDIAN
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
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
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
; Digit font (in Chip RAM via code_c section)
even
digit_font:
; 0
dc.w $3c00
dc.w $6600
dc.w $6e00
dc.w $7e00
dc.w $7600
dc.w $6600
dc.w $3c00
dc.w $0000
; 1
dc.w $1800
dc.w $3800
dc.w $1800
dc.w $1800
dc.w $1800
dc.w $1800
dc.w $7e00
dc.w $0000
; 2
dc.w $3c00
dc.w $6600
dc.w $0600
dc.w $1c00
dc.w $3000
dc.w $6000
dc.w $7e00
dc.w $0000
; 3
dc.w $3c00
dc.w $6600
dc.w $0600
dc.w $1c00
dc.w $0600
dc.w $6600
dc.w $3c00
dc.w $0000
; 4
dc.w $0c00
dc.w $1c00
dc.w $3c00
dc.w $6c00
dc.w $7e00
dc.w $0c00
dc.w $0c00
dc.w $0000
; 5
dc.w $7e00
dc.w $6000
dc.w $7c00
dc.w $0600
dc.w $0600
dc.w $6600
dc.w $3c00
dc.w $0000
; 6
dc.w $1c00
dc.w $3000
dc.w $6000
dc.w $7c00
dc.w $6600
dc.w $6600
dc.w $3c00
dc.w $0000
; 7
dc.w $7e00
dc.w $0600
dc.w $0c00
dc.w $1800
dc.w $3000
dc.w $3000
dc.w $3000
dc.w $0000
; 8
dc.w $3c00
dc.w $6600
dc.w $6600
dc.w $3c00
dc.w $6600
dc.w $6600
dc.w $3c00
dc.w $0000
; 9
dc.w $3c00
dc.w $6600
dc.w $6600
dc.w $3e00
dc.w $0600
dc.w $0c00
dc.w $3800
dc.w $0000
;==============================================================================
; SOUND DATA (must be in Chip RAM for Paula DMA)
;==============================================================================
even
sound_hop:
dc.b $7f,$7f,$7f,$7f,$7f,$7f,$7f,$7f
dc.b $80,$80,$80,$80,$80,$80,$80,$80
dc.b $7f,$7f,$7f,$7f,$7f,$7f,$7f,$7f
dc.b $80,$80,$80,$80,$80,$80,$80,$80
HOP_LEN equ *-sound_hop
sound_death:
dc.b $7f,$7f,$7f,$7f,$80,$80,$80,$80
dc.b $7f,$7f,$7f,$7f,$80,$80,$80,$80
dc.b $7f,$7f,$7f,$7f,$7f,$80,$80,$80,$80,$80
dc.b $7f,$7f,$7f,$7f,$7f,$7f,$80,$80,$80,$80,$80,$80
dc.b $7f,$7f,$7f,$7f,$7f,$7f,$7f,$7f
dc.b $80,$80,$80,$80,$80,$80,$80,$80
DEATH_LEN equ *-sound_death
sound_home:
dc.b $7f,$80,$7f,$80,$7f,$80,$7f,$80
dc.b $7f,$80,$7f,$80,$7f,$80,$7f,$80
dc.b $7f,$7f,$80,$80,$7f,$7f,$80,$80
dc.b $7f,$7f,$80,$80,$7f,$7f,$80,$80
dc.b $7f,$7f,$7f,$80,$80,$80,$7f,$7f,$7f,$80,$80,$80
dc.b $00,$00,$00,$00
HOME_LEN equ *-sound_home
;==============================================================================
; SCREEN BUFFER
;==============================================================================
section chipbss,bss_c
even
screen_plane:
ds.b PLANE_SIZE
Build It
vasmm68k_mot -Fhunkexe -kick1hunks -o signal signal.asmWhat’s Next
The game tracks and displays score, but has no time pressure. In Unit 13, we’ll add a countdown timer that creates urgency and awards bonus points for speed.
What Changed
Unit 11 → Unit 12
+212-65
| 1 | 1 | ;============================================================================== | |
| 2 | 2 | ; SIGNAL - A Frogger-style game for the Commodore Amiga | |
| 3 | - | ; Unit 11: Sound Effects | |
| 3 | + | ; Unit 12: Score Display | |
| 4 | 4 | ; | |
| 5 | - | ; A game without sound feels lifeless. This unit adds audio feedback using | |
| 6 | - | ; Paula, the Amiga's sound chip. Simple 8-bit waveforms play when you hop, | |
| 7 | - | ; die, or reach a home zone. | |
| 5 | + | ; Tracking points internally is useless if players can't see them. This unit | |
| 6 | + | ; adds score display using bitmap digits. We convert the binary score to | |
| 7 | + | ; decimal and draw each digit using the Blitter. | |
| 8 | 8 | ;============================================================================== | |
| 9 | 9 | | |
| 10 | 10 | ;============================================================================== | |
| ... | |||
| 48 | 48 | ROAD_ROW_FIRST equ 7 | |
| 49 | 49 | ROAD_ROW_LAST equ 11 | |
| 50 | 50 | | |
| 51 | - | ; Lives system | |
| 52 | 51 | START_LIVES equ 3 | |
| 53 | 52 | | |
| 54 | - | ; Home zones | |
| 55 | 53 | NUM_HOMES equ 5 | |
| 56 | 54 | HOME_ROW equ 0 | |
| 57 | 55 | POINTS_PER_HOME equ 50 | |
| ... | |||
| 61 | 59 | HOME_2_X equ 10 | |
| 62 | 60 | HOME_3_X equ 14 | |
| 63 | 61 | HOME_4_X equ 18 | |
| 62 | + | | |
| 63 | + | ; Score display - position in start zone (below cars) | |
| 64 | + | SCORE_X equ 256 ; Pixel X position (must be byte-aligned) | |
| 65 | + | SCORE_Y equ 236 ; Pixel Y position (grid row 12, in start zone) | |
| 66 | + | DIGIT_H equ 8 ; 8 pixels tall | |
| 67 | + | NUM_DIGITS equ 6 ; Display 6 digits (up to 999,999) | |
| 64 | 68 | | |
| 65 | 69 | ; Audio constants | |
| 66 | 70 | SND_HOP equ 0 | |
| ... | |||
| 107 | 111 | BLTBMOD equ $062 | |
| 108 | 112 | BLTAMOD equ $064 | |
| 109 | 113 | BLTDMOD equ $066 | |
| 114 | + | BLTADAT equ $074 | |
| 110 | 115 | | |
| 111 | 116 | COP1LC equ $080 | |
| 112 | 117 | COPJMP1 equ $088 | |
| ... | |||
| 121 | 126 | SPR2PTH equ $128 | |
| 122 | 127 | SPR2PTL equ $12a | |
| 123 | 128 | | |
| 124 | - | ; Paula audio registers (channel 0) | |
| 125 | - | AUD0LC equ $0a0 ; Sample pointer (long) | |
| 126 | - | AUD0LEN equ $0a4 ; Sample length in words | |
| 127 | - | AUD0PER equ $0a6 ; Period (lower = higher pitch) | |
| 128 | - | AUD0VOL equ $0a8 ; Volume (0-64) | |
| 129 | + | AUD0LC equ $0a0 | |
| 130 | + | AUD0LEN equ $0a4 | |
| 131 | + | AUD0PER equ $0a6 | |
| 132 | + | AUD0VOL equ $0a8 | |
| 129 | 133 | | |
| 130 | 134 | ;============================================================================== | |
| 131 | 135 | ; CODE SECTION | |
| ... | |||
| 139 | 143 | move.w #$7fff,INTENA(a5) | |
| 140 | 144 | move.w #$7fff,INTREQ(a5) | |
| 141 | 145 | move.w #$7fff,DMACON(a5) | |
| 146 | + | | |
| 147 | + | ; Enable Blitter DMA for screen clearing and drawing | |
| 148 | + | move.w #$8040,DMACON(a5) ; BLTDMA on | |
| 142 | 149 | | |
| 143 | 150 | bsr clear_screen | |
| 144 | 151 | | |
| ... | |||
| 155 | 162 | ; Initialise game | |
| 156 | 163 | bsr init_game | |
| 157 | 164 | | |
| 158 | - | ; Set main sprite pointer (sprite 0 = frog) | |
| 165 | + | ; Set main sprite pointer | |
| 159 | 166 | lea frog_data,a0 | |
| 160 | 167 | move.l a0,d0 | |
| 161 | 168 | swap d0 | |
| ... | |||
| 165 | 172 | lea sprptl_val,a1 | |
| 166 | 173 | move.w d0,(a1) | |
| 167 | 174 | | |
| 168 | - | ; Set up life icon sprites | |
| 169 | 175 | bsr setup_life_sprites | |
| 170 | 176 | | |
| 171 | 177 | bsr update_sprite | |
| ... | |||
| 176 | 182 | move.l a0,COP1LC(a5) | |
| 177 | 183 | move.w d0,COPJMP1(a5) | |
| 178 | 184 | | |
| 179 | - | ; Enable DMA (including audio channel 0) | |
| 180 | - | move.w #$87e1,DMACON(a5) ; +AUD0 | |
| 185 | + | move.w #$87e1,DMACON(a5) | |
| 186 | + | | |
| 187 | + | ; Display score after all DMA enabled | |
| 188 | + | bsr display_score | |
| 181 | 189 | | |
| 182 | 190 | ;============================================================================== | |
| 183 | 191 | ; MAIN LOOP | |
| ... | |||
| 186 | 194 | mainloop: | |
| 187 | 195 | bsr wait_vblank | |
| 188 | 196 | | |
| 189 | - | ; Check game state | |
| 190 | 197 | cmp.w #STATE_GAMEOVER,frog_state | |
| 191 | 198 | beq .game_over_loop | |
| 192 | 199 | | |
| 193 | - | ; Normal game loop | |
| 194 | 200 | bsr update_frog | |
| 195 | 201 | bsr update_sprite | |
| 196 | 202 | | |
| ... | |||
| 212 | 218 | btst #7,$bfe001 | |
| 213 | 219 | bne.s mainloop | |
| 214 | 220 | | |
| 215 | - | ; Restart game | |
| 216 | 221 | bsr init_game | |
| 217 | 222 | bsr update_life_display | |
| 223 | + | bsr display_score | |
| 218 | 224 | bsr clear_screen | |
| 219 | 225 | | |
| 220 | 226 | bra mainloop | |
| 221 | 227 | | |
| 222 | 228 | ;============================================================================== | |
| 223 | - | ; SOUND ROUTINES | |
| 229 | + | ; SCORE DISPLAY | |
| 224 | 230 | ;============================================================================== | |
| 225 | 231 | | |
| 226 | 232 | ;------------------------------------------------------------------------------ | |
| 227 | - | ; PLAY_SOUND - Play a sound effect | |
| 228 | - | ; Input: D0 = sound number (SND_HOP, SND_DEATH, SND_HOME) | |
| 233 | + | ; DISPLAY_SCORE - Convert score to digits and display | |
| 234 | + | ; Simplified: just draws "000000" for now | |
| 235 | + | ;------------------------------------------------------------------------------ | |
| 236 | + | display_score: | |
| 237 | + | movem.l d0-d4/a0-a3,-(sp) | |
| 238 | + | | |
| 239 | + | ; Convert score to 6 decimal digits | |
| 240 | + | move.l score(pc),d0 ; Use PC-relative addressing | |
| 241 | + | | |
| 242 | + | lea score_digits+12,a0 ; Point past end of buffer | |
| 243 | + | moveq #5,d4 | |
| 244 | + | .convert: | |
| 245 | + | divu #10,d0 ; d0 low = quotient, d0 high = remainder | |
| 246 | + | swap d0 | |
| 247 | + | move.w d0,-(a0) ; Store remainder | |
| 248 | + | clr.w d0 | |
| 249 | + | swap d0 | |
| 250 | + | dbf d4,.convert | |
| 251 | + | | |
| 252 | + | ; Draw 6 digits using CPU byte copies (tight 8-pixel spacing) | |
| 253 | + | lea score_digits,a1 ; Digit values | |
| 254 | + | lea screen_plane,a2 | |
| 255 | + | add.l #SCORE_Y*SCREEN_W+SCORE_X/8,a2 ; Base destination | |
| 256 | + | | |
| 257 | + | moveq #5,d4 ; 6 digits | |
| 258 | + | .draw_digit: | |
| 259 | + | move.w (a1)+,d0 ; Get digit value (0-9) | |
| 260 | + | lsl.w #4,d0 ; *16: each digit = 16 bytes | |
| 261 | + | lea digit_font,a0 | |
| 262 | + | add.w d0,a0 ; Point to correct digit | |
| 263 | + | | |
| 264 | + | ; Copy 8 rows, 1 byte each (CPU, no alignment issues) | |
| 265 | + | move.l a2,a3 ; Dest for this digit | |
| 266 | + | moveq #7,d3 ; 8 rows | |
| 267 | + | .copy_row: | |
| 268 | + | move.b (a0),(a3) ; Copy high byte of word | |
| 269 | + | addq.l #2,a0 ; Next source word | |
| 270 | + | lea SCREEN_W(a3),a3 ; Next dest row | |
| 271 | + | dbf d3,.copy_row | |
| 272 | + | | |
| 273 | + | addq.l #1,a2 ; Move right by 1 byte (8 pixels) | |
| 274 | + | dbf d4,.draw_digit | |
| 275 | + | | |
| 276 | + | movem.l (sp)+,d0-d4/a0-a3 | |
| 277 | + | rts | |
| 278 | + | | |
| 279 | + | ;------------------------------------------------------------------------------ | |
| 280 | + | ; CALC_PIXEL_ADDR - Calculate screen address for pixel coordinates | |
| 281 | + | ; Input: D0 = X, D1 = Y | |
| 282 | + | ; Output: A2 = screen address | |
| 229 | 283 | ;------------------------------------------------------------------------------ | |
| 284 | + | calc_pixel_addr: | |
| 285 | + | lea screen_plane,a2 | |
| 286 | + | move.w d1,d2 | |
| 287 | + | mulu #SCREEN_W,d2 | |
| 288 | + | add.l d2,a2 | |
| 289 | + | move.w d0,d2 | |
| 290 | + | lsr.w #3,d2 | |
| 291 | + | ext.l d2 | |
| 292 | + | add.l d2,a2 | |
| 293 | + | rts | |
| 294 | + | | |
| 295 | + | ;============================================================================== | |
| 296 | + | ; SOUND ROUTINES | |
| 297 | + | ;============================================================================== | |
| 298 | + | | |
| 230 | 299 | play_sound: | |
| 231 | - | ; Get sound data address and parameters | |
| 232 | 300 | cmp.w #SND_HOP,d0 | |
| 233 | 301 | beq.s .play_hop | |
| 234 | 302 | cmp.w #SND_DEATH,d0 | |
| ... | |||
| 239 | 307 | | |
| 240 | 308 | .play_hop: | |
| 241 | 309 | lea sound_hop,a0 | |
| 242 | - | move.w #HOP_LEN/2,d1 ; Length in words | |
| 243 | - | move.w #300,d2 ; Period (medium pitch) | |
| 310 | + | move.w #HOP_LEN/2,d1 | |
| 311 | + | move.w #300,d2 | |
| 244 | 312 | bra.s .do_play | |
| 245 | 313 | | |
| 246 | 314 | .play_death: | |
| 247 | 315 | lea sound_death,a0 | |
| 248 | 316 | move.w #DEATH_LEN/2,d1 | |
| 249 | - | move.w #500,d2 ; Period (lower pitch) | |
| 317 | + | move.w #500,d2 | |
| 250 | 318 | bra.s .do_play | |
| 251 | 319 | | |
| 252 | 320 | .play_home: | |
| 253 | 321 | lea sound_home,a0 | |
| 254 | 322 | move.w #HOME_LEN/2,d1 | |
| 255 | - | move.w #200,d2 ; Period (higher pitch) | |
| 323 | + | move.w #200,d2 | |
| 256 | 324 | | |
| 257 | 325 | .do_play: | |
| 258 | - | ; Stop any playing sound first | |
| 259 | - | move.w #$0001,DMACON(a5) ; Disable AUD0 | |
| 260 | - | | |
| 261 | - | ; Set sample pointer | |
| 326 | + | move.w #$0001,DMACON(a5) | |
| 262 | 327 | move.l a0,AUD0LC(a5) | |
| 263 | - | | |
| 264 | - | ; Set length (in words) | |
| 265 | 328 | move.w d1,AUD0LEN(a5) | |
| 266 | - | | |
| 267 | - | ; Set period | |
| 268 | 329 | move.w d2,AUD0PER(a5) | |
| 269 | - | | |
| 270 | - | ; Set volume (max = 64) | |
| 271 | 330 | move.w #64,AUD0VOL(a5) | |
| 272 | - | | |
| 273 | - | ; Enable audio DMA | |
| 274 | - | move.w #$8001,DMACON(a5) ; Enable AUD0 | |
| 275 | - | | |
| 331 | + | move.w #$8001,DMACON(a5) | |
| 276 | 332 | rts | |
| 277 | 333 | | |
| 278 | 334 | ;============================================================================== | |
| ... | |||
| 305 | 361 | move.w frog_grid_x,d0 | |
| 306 | 362 | | |
| 307 | 363 | cmp.w #HOME_0_X,d0 | |
| 308 | - | blt.s .not_home | |
| 364 | + | blt .not_home | |
| 309 | 365 | cmp.w #HOME_0_X+2,d0 | |
| 310 | 366 | blt.s .home_0 | |
| 311 | 367 | | |
| 312 | 368 | cmp.w #HOME_1_X,d0 | |
| 313 | - | blt.s .not_home | |
| 369 | + | blt .not_home | |
| 314 | 370 | cmp.w #HOME_1_X+2,d0 | |
| 315 | 371 | blt.s .home_1 | |
| 316 | 372 | | |
| 317 | 373 | cmp.w #HOME_2_X,d0 | |
| 318 | - | blt.s .not_home | |
| 374 | + | blt .not_home | |
| 319 | 375 | cmp.w #HOME_2_X+2,d0 | |
| 320 | 376 | blt.s .home_2 | |
| 321 | 377 | | |
| 322 | 378 | cmp.w #HOME_3_X,d0 | |
| 323 | - | blt.s .not_home | |
| 379 | + | blt .not_home | |
| 324 | 380 | cmp.w #HOME_3_X+2,d0 | |
| 325 | 381 | blt.s .home_3 | |
| 326 | 382 | | |
| 327 | 383 | cmp.w #HOME_4_X,d0 | |
| 328 | - | blt.s .not_home | |
| 384 | + | blt .not_home | |
| 329 | 385 | cmp.w #HOME_4_X+2,d0 | |
| 330 | 386 | blt.s .home_4 | |
| 331 | 387 | | |
| ... | |||
| 350 | 406 | move.w #1,0(a0,d1.w) | |
| 351 | 407 | add.l #POINTS_PER_HOME,score | |
| 352 | 408 | | |
| 353 | - | ; Play success sound | |
| 354 | 409 | move.w #SND_HOME,d0 | |
| 355 | 410 | bsr play_sound | |
| 356 | 411 | | |
| 357 | 412 | bsr update_home_display | |
| 413 | + | bsr display_score ; Update score display | |
| 358 | 414 | bsr check_round_complete | |
| 359 | 415 | bsr reset_frog | |
| 360 | 416 | rts | |
| ... | |||
| 553 | 609 | move.w #DEATH_FRAMES,death_timer | |
| 554 | 610 | move.w #FLASH_COLOUR,flash_colour | |
| 555 | 611 | | |
| 556 | - | ; Play death sound | |
| 557 | 612 | move.w #SND_DEATH,d0 | |
| 558 | 613 | bsr play_sound | |
| 559 | 614 | | |
| ... | |||
| 729 | 784 | move.w #STATE_HOPPING,frog_state | |
| 730 | 785 | clr.w frog_anim_frame | |
| 731 | 786 | | |
| 732 | - | ; Play hop sound | |
| 733 | 787 | move.w #SND_HOP,d0 | |
| 734 | 788 | bsr play_sound | |
| 735 | 789 | | |
| ... | |||
| 887 | 941 | score: dc.l 0 | |
| 888 | 942 | | |
| 889 | 943 | home_filled: dc.w 0,0,0,0,0 | |
| 944 | + | | |
| 945 | + | ; Buffer for score digits | |
| 946 | + | score_digits: dc.w 0,0,0,0,0,0 | |
| 890 | 947 | | |
| 891 | 948 | car_data: | |
| 892 | 949 | dc.w 0,7,1,0 | |
| ... | |||
| 1113 | 1170 | dc.w $1800,$0000 | |
| 1114 | 1171 | dc.w $0000,$0000 | |
| 1115 | 1172 | dc.w $0000,$0000 | |
| 1173 | + | | |
| 1174 | + | ; Digit font (in Chip RAM via code_c section) | |
| 1175 | + | even | |
| 1176 | + | digit_font: | |
| 1177 | + | ; 0 | |
| 1178 | + | dc.w $3c00 | |
| 1179 | + | dc.w $6600 | |
| 1180 | + | dc.w $6e00 | |
| 1181 | + | dc.w $7e00 | |
| 1182 | + | dc.w $7600 | |
| 1183 | + | dc.w $6600 | |
| 1184 | + | dc.w $3c00 | |
| 1185 | + | dc.w $0000 | |
| 1186 | + | ; 1 | |
| 1187 | + | dc.w $1800 | |
| 1188 | + | dc.w $3800 | |
| 1189 | + | dc.w $1800 | |
| 1190 | + | dc.w $1800 | |
| 1191 | + | dc.w $1800 | |
| 1192 | + | dc.w $1800 | |
| 1193 | + | dc.w $7e00 | |
| 1194 | + | dc.w $0000 | |
| 1195 | + | ; 2 | |
| 1196 | + | dc.w $3c00 | |
| 1197 | + | dc.w $6600 | |
| 1198 | + | dc.w $0600 | |
| 1199 | + | dc.w $1c00 | |
| 1200 | + | dc.w $3000 | |
| 1201 | + | dc.w $6000 | |
| 1202 | + | dc.w $7e00 | |
| 1203 | + | dc.w $0000 | |
| 1204 | + | ; 3 | |
| 1205 | + | dc.w $3c00 | |
| 1206 | + | dc.w $6600 | |
| 1207 | + | dc.w $0600 | |
| 1208 | + | dc.w $1c00 | |
| 1209 | + | dc.w $0600 | |
| 1210 | + | dc.w $6600 | |
| 1211 | + | dc.w $3c00 | |
| 1212 | + | dc.w $0000 | |
| 1213 | + | ; 4 | |
| 1214 | + | dc.w $0c00 | |
| 1215 | + | dc.w $1c00 | |
| 1216 | + | dc.w $3c00 | |
| 1217 | + | dc.w $6c00 | |
| 1218 | + | dc.w $7e00 | |
| 1219 | + | dc.w $0c00 | |
| 1220 | + | dc.w $0c00 | |
| 1221 | + | dc.w $0000 | |
| 1222 | + | ; 5 | |
| 1223 | + | dc.w $7e00 | |
| 1224 | + | dc.w $6000 | |
| 1225 | + | dc.w $7c00 | |
| 1226 | + | dc.w $0600 | |
| 1227 | + | dc.w $0600 | |
| 1228 | + | dc.w $6600 | |
| 1229 | + | dc.w $3c00 | |
| 1230 | + | dc.w $0000 | |
| 1231 | + | ; 6 | |
| 1232 | + | dc.w $1c00 | |
| 1233 | + | dc.w $3000 | |
| 1234 | + | dc.w $6000 | |
| 1235 | + | dc.w $7c00 | |
| 1236 | + | dc.w $6600 | |
| 1237 | + | dc.w $6600 | |
| 1238 | + | dc.w $3c00 | |
| 1239 | + | dc.w $0000 | |
| 1240 | + | ; 7 | |
| 1241 | + | dc.w $7e00 | |
| 1242 | + | dc.w $0600 | |
| 1243 | + | dc.w $0c00 | |
| 1244 | + | dc.w $1800 | |
| 1245 | + | dc.w $3000 | |
| 1246 | + | dc.w $3000 | |
| 1247 | + | dc.w $3000 | |
| 1248 | + | dc.w $0000 | |
| 1249 | + | ; 8 | |
| 1250 | + | dc.w $3c00 | |
| 1251 | + | dc.w $6600 | |
| 1252 | + | dc.w $6600 | |
| 1253 | + | dc.w $3c00 | |
| 1254 | + | dc.w $6600 | |
| 1255 | + | dc.w $6600 | |
| 1256 | + | dc.w $3c00 | |
| 1257 | + | dc.w $0000 | |
| 1258 | + | ; 9 | |
| 1259 | + | dc.w $3c00 | |
| 1260 | + | dc.w $6600 | |
| 1261 | + | dc.w $6600 | |
| 1262 | + | dc.w $3e00 | |
| 1263 | + | dc.w $0600 | |
| 1264 | + | dc.w $0c00 | |
| 1265 | + | dc.w $3800 | |
| 1266 | + | dc.w $0000 | |
| 1116 | 1267 | | |
| 1117 | 1268 | ;============================================================================== | |
| 1118 | - | ; SOUND DATA (8-bit signed samples in Chip RAM) | |
| 1269 | + | ; SOUND DATA (must be in Chip RAM for Paula DMA) | |
| 1119 | 1270 | ;============================================================================== | |
| 1120 | 1271 | | |
| 1121 | 1272 | even | |
| 1122 | - | | |
| 1123 | - | ; Hop sound - short square wave burst (32 bytes = 16 words) | |
| 1124 | 1273 | sound_hop: | |
| 1125 | - | dc.b $7f,$7f,$7f,$7f,$7f,$7f,$7f,$7f ; High | |
| 1126 | - | dc.b $80,$80,$80,$80,$80,$80,$80,$80 ; Low | |
| 1127 | - | dc.b $7f,$7f,$7f,$7f,$7f,$7f,$7f,$7f ; High | |
| 1128 | - | dc.b $80,$80,$80,$80,$80,$80,$80,$80 ; Low | |
| 1274 | + | dc.b $7f,$7f,$7f,$7f,$7f,$7f,$7f,$7f | |
| 1275 | + | dc.b $80,$80,$80,$80,$80,$80,$80,$80 | |
| 1276 | + | dc.b $7f,$7f,$7f,$7f,$7f,$7f,$7f,$7f | |
| 1277 | + | dc.b $80,$80,$80,$80,$80,$80,$80,$80 | |
| 1129 | 1278 | HOP_LEN equ *-sound_hop | |
| 1130 | 1279 | | |
| 1131 | - | ; Death sound - descending tone (64 bytes = 32 words) | |
| 1132 | 1280 | sound_death: | |
| 1133 | - | dc.b $7f,$7f,$7f,$7f,$80,$80,$80,$80 ; Fast cycle | |
| 1134 | 1281 | dc.b $7f,$7f,$7f,$7f,$80,$80,$80,$80 | |
| 1135 | - | dc.b $7f,$7f,$7f,$7f,$7f,$80,$80,$80,$80,$80 ; Slower | |
| 1136 | - | dc.b $7f,$7f,$7f,$7f,$7f,$7f,$80,$80,$80,$80,$80,$80 ; Slower still | |
| 1137 | - | dc.b $7f,$7f,$7f,$7f,$7f,$7f,$7f,$7f ; Even slower | |
| 1282 | + | dc.b $7f,$7f,$7f,$7f,$80,$80,$80,$80 | |
| 1283 | + | dc.b $7f,$7f,$7f,$7f,$7f,$80,$80,$80,$80,$80 | |
| 1284 | + | dc.b $7f,$7f,$7f,$7f,$7f,$7f,$80,$80,$80,$80,$80,$80 | |
| 1285 | + | dc.b $7f,$7f,$7f,$7f,$7f,$7f,$7f,$7f | |
| 1138 | 1286 | dc.b $80,$80,$80,$80,$80,$80,$80,$80 | |
| 1139 | 1287 | DEATH_LEN equ *-sound_death | |
| 1140 | 1288 | | |
| 1141 | - | ; Home sound - bright chirp (48 bytes = 24 words) | |
| 1142 | 1289 | sound_home: | |
| 1143 | - | dc.b $7f,$80,$7f,$80,$7f,$80,$7f,$80 ; Fast high | |
| 1144 | 1290 | dc.b $7f,$80,$7f,$80,$7f,$80,$7f,$80 | |
| 1145 | - | dc.b $7f,$7f,$80,$80,$7f,$7f,$80,$80 ; Medium | |
| 1291 | + | dc.b $7f,$80,$7f,$80,$7f,$80,$7f,$80 | |
| 1146 | 1292 | dc.b $7f,$7f,$80,$80,$7f,$7f,$80,$80 | |
| 1147 | - | dc.b $7f,$7f,$7f,$80,$80,$80,$7f,$7f,$7f,$80,$80,$80 ; Lower finish | |
| 1148 | - | dc.b $00,$00,$00,$00 ; Silence | |
| 1293 | + | dc.b $7f,$7f,$80,$80,$7f,$7f,$80,$80 | |
| 1294 | + | dc.b $7f,$7f,$7f,$80,$80,$80,$7f,$7f,$7f,$80,$80,$80 | |
| 1295 | + | dc.b $00,$00,$00,$00 | |
| 1149 | 1296 | HOME_LEN equ *-sound_home | |
| 1150 | 1297 | | |
| 1151 | 1298 | ;============================================================================== |