mirror of
https://github.com/deater/dos33fsprogs.git
synced 2024-11-18 21:06:31 +00:00
844 lines
16 KiB
ArmAsm
844 lines
16 KiB
ArmAsm
;=======================================================================
|
|
; Based on BASIC program posted by FozzTexx, originally written in 1987
|
|
;=======================================================================
|
|
|
|
; State:
|
|
; 0: Launch Rocket -> goes to 1
|
|
; 1: Move Rocket -> repeats 1 until CS done, then 2
|
|
; 2: Start Explosion -> goes to 3
|
|
; 3: Continue Explosion -> repeats 3 until done.
|
|
; then randomly might go to 2
|
|
; before going to 0
|
|
|
|
|
|
STATE_LAUNCH_ROCKET = 0
|
|
STATE_MOVE_ROCKET = 2
|
|
STATE_START_EXPLOSION = 4
|
|
STATE_CONTINUE_EXPLOSION = 6
|
|
STATE_STALL_ROCKET = 8
|
|
|
|
; Constants
|
|
NUMSTARS = 16
|
|
YSIZE = 160
|
|
XSIZE = 280
|
|
MARGIN = 24
|
|
|
|
; Zero page addresses
|
|
;STATE = $ED
|
|
OFFSET = $EF
|
|
COLOR_GROUP = $F0
|
|
X_VELOCITY = $F1
|
|
Y_VELOCITY_H = $F2
|
|
Y_VELOCITY_L = $F3
|
|
MAX_STEPS = $F4
|
|
XPOS_H = $F5
|
|
XPOS_L = $F6
|
|
YPOS_H = $F7
|
|
YPOS_L = $F8
|
|
PEAK = $F9
|
|
CURRENT_STEP = $FA
|
|
Y_OLD = $FB
|
|
Y_OLDER = $FC
|
|
X_OLD = $FD
|
|
X_OLDER = $FE
|
|
TEMPY = $FF
|
|
|
|
.align $100
|
|
|
|
;===========================
|
|
; LAUNCH_FIREWORK
|
|
;===========================
|
|
; cycles= 60+60+67+60+56+56+15+8+21+11 = 414
|
|
|
|
launch_firework:
|
|
|
|
sound1:
|
|
bit SPEAKER ; 4
|
|
|
|
jsr random16 ; 6+42
|
|
lda SEEDL ; 3
|
|
and #$4 ; 2
|
|
sta COLOR_GROUP ; HGR color group (0 PG or 4 BO) ; 3
|
|
;============
|
|
; 60
|
|
|
|
jsr random16 ; 6+42
|
|
lda SEEDL ; 3
|
|
and #$3 ; 2
|
|
clc ; 2
|
|
adc #$1 ; 2
|
|
sta X_VELOCITY ; x velocity = 1..4 ; 3
|
|
;===========
|
|
; 60
|
|
|
|
|
|
jsr random16 ; 6+42
|
|
lda SEEDL ; 3
|
|
and #$3 ; 2
|
|
clc ; 2
|
|
adc #$2 ; 2
|
|
eor #$ff ; 2
|
|
sta Y_VELOCITY_H ; y velocity = -3..-6 ; 3
|
|
lda #0 ; 2
|
|
sta Y_VELOCITY_L ; it's 8:8 fixed point ; 3
|
|
;============
|
|
; 67
|
|
|
|
jsr random16 ; 6+42
|
|
lda SEEDL ; 3
|
|
and #$1f ; 2
|
|
clc ; 2
|
|
adc #33 ; 2
|
|
sta MAX_STEPS ; 33..64 ; 3
|
|
;============
|
|
; 60
|
|
|
|
; launch from the two hills
|
|
jsr random16 ; 6+42
|
|
lda SEEDL ; 3
|
|
and #$3f ; 2
|
|
sta XPOS_L ; base of 0..63 ; 3
|
|
;============
|
|
; 56
|
|
|
|
jsr random16 ; 6+42
|
|
lda SEEDL ; 3
|
|
and #$1 ; 2
|
|
|
|
beq right_hill ; 3
|
|
;============
|
|
; 56
|
|
|
|
|
|
|
|
left_hill: ;-1
|
|
lda X_VELOCITY ; nop ; 3
|
|
lda X_VELOCITY ; nop ; 3
|
|
lda X_VELOCITY ; nop ; 3
|
|
nop ; 2
|
|
lda #24 ; make it 24..87 ; 2
|
|
jmp done_hill ; 3
|
|
;===========
|
|
; 15
|
|
|
|
right_hill:
|
|
lda X_VELOCITY ; 3
|
|
eor #$ff ; 2
|
|
sta X_VELOCITY ; 3
|
|
inc X_VELOCITY ; aim toward middle ; 5
|
|
|
|
lda #191 ; make it 191..254 ; 2
|
|
;===========
|
|
; 15
|
|
|
|
done_hill:
|
|
clc ; 2
|
|
adc XPOS_L ; 3
|
|
sta XPOS_L ; 3
|
|
|
|
;===========
|
|
; 8
|
|
|
|
lda #YSIZE ; 2
|
|
sta YPOS_H ; 3
|
|
lda #0 ; fixed point 8:8 ; 2
|
|
sta YPOS_L ; start at ground ; 3
|
|
|
|
lda YPOS_H ; 3
|
|
sta PEAK ; peak starts at ground ; 3
|
|
|
|
lda #1 ; 2
|
|
sta CURRENT_STEP ; 3
|
|
;===========
|
|
; 21
|
|
|
|
lda #STATE_MOVE_ROCKET ; 2
|
|
sta STATE ; move to launch ; 3
|
|
|
|
rts ; 6
|
|
;============
|
|
; 11
|
|
|
|
|
|
.align $100
|
|
|
|
;==========================================================================
|
|
; Move rocket
|
|
;==========================================================================
|
|
; cycles=24+11+20+18+14+53 = 140+1096 = 1236
|
|
|
|
move_rocket:
|
|
|
|
; save old values
|
|
lda Y_OLD ; 3
|
|
sta Y_OLDER ; 3
|
|
lda YPOS_H ; 3
|
|
sta Y_OLD ; 3
|
|
lda X_OLD ; 3
|
|
sta X_OLDER ; 3
|
|
lda XPOS_L ; 3
|
|
sta X_OLD ; 3
|
|
;===========
|
|
; 24
|
|
|
|
; Move xpos
|
|
lda XPOS_L ; 3
|
|
clc ; 2
|
|
adc X_VELOCITY ; 3
|
|
sta XPOS_L ; 3
|
|
;============
|
|
; 11
|
|
; Move ypos, 16-bit add
|
|
clc ; 2
|
|
lda YPOS_L ; 3
|
|
adc Y_VELOCITY_L ; 3
|
|
sta YPOS_L ; 3
|
|
lda YPOS_H ; 3
|
|
adc Y_VELOCITY_H ; 3
|
|
sta YPOS_H ; 3
|
|
;===========
|
|
; 20
|
|
|
|
; adjust Y velocity, slow it down
|
|
clc ; 2
|
|
lda Y_VELOCITY_L ; 3
|
|
adc #$20 ; $20 = 0.125 ; 2
|
|
sta Y_VELOCITY_L ; 3
|
|
lda Y_VELOCITY_H ; 3
|
|
adc #0 ; 2
|
|
sta Y_VELOCITY_H ; 3
|
|
;===========
|
|
; 18
|
|
; if we went higher, adjust peak
|
|
lda YPOS_H ; 3
|
|
cmp PEAK ; 3
|
|
bcc no_peak_nop ; blt ; 3
|
|
|
|
;-1
|
|
sta PEAK ; 3
|
|
jmp no_peak ; 3
|
|
no_peak_nop:
|
|
nop ; 2
|
|
jmp no_peak ; 3
|
|
no_peak:
|
|
;=============
|
|
; 14
|
|
|
|
;========================================
|
|
; Check if out of bounds and stop moving
|
|
;========================================
|
|
; bcc = 8+7+12+20+6 = 53
|
|
; bcs/bcc = 8+7+12+20+6 = 53
|
|
; bcs/bcs/bmi = 8+7+5+33 = 53
|
|
; bcs/bcs/bpl/bcs = 8+7+5+7+20+6 = 53
|
|
; bcs/bcs/bpl/bcc/bcc = 8+7+5+7+20+6 = 53
|
|
; bcs/bcs/bpl/bcc/bcs = 8+7+5+7+20+6 = 53
|
|
|
|
lda XPOS_L ; if (xpos_l<=margin) too far left ; 3
|
|
cmp #MARGIN ; 2
|
|
bcc done_moving_first ; 3
|
|
;===========
|
|
; 8
|
|
|
|
; Due to 256 wraparound, the above will catch this case???
|
|
; cmp #XSIZE-MARGIN ; if (xpos_l>=(xsize-margin)) too far right
|
|
; bcs done_moving
|
|
|
|
; -1
|
|
lda YPOS_H ; if (ypos_h<=margin) too far up ; 3
|
|
cmp #MARGIN ; 2
|
|
bcc done_moving_second ; 3
|
|
;===========
|
|
; 7
|
|
;======================
|
|
; if falling downward
|
|
;======================
|
|
; -1
|
|
lda Y_VELOCITY_H ; 3
|
|
bmi going_up ; if (y_velocity_h>0) ; 3
|
|
;============
|
|
; 5
|
|
|
|
; if too close to ground, explode ; -1
|
|
lda YPOS_H ; if (ypos_h>=ysize-margin) ; 3
|
|
cmp #(YSIZE-MARGIN) ; 2
|
|
bcs done_moving_third ; 3
|
|
;============
|
|
; 7
|
|
|
|
; if fallen a bit past peak, explode ; -1
|
|
sec ; if (ypos_h>ysize-(ysize-peak)/2) ; 2
|
|
lda #YSIZE ; 2
|
|
sbc PEAK ; 3
|
|
lsr ; 2
|
|
eor #$FF ; 2
|
|
sec ; 2
|
|
adc #YSIZE ; 2
|
|
cmp YPOS_H ; 3
|
|
bcc done_moving ; 3
|
|
;===========
|
|
; 20
|
|
|
|
|
|
;-1
|
|
done_moving_ft:
|
|
nop ; 2
|
|
nop ; 2
|
|
jmp done_bounds_checking ; 3
|
|
;===========
|
|
; 6
|
|
|
|
going_up:
|
|
; 33 cycles
|
|
lda MAX_STEPS ; 3
|
|
lda MAX_STEPS ; 3
|
|
lda MAX_STEPS ; 3
|
|
lda MAX_STEPS ; 3
|
|
lda MAX_STEPS ; 3
|
|
lda MAX_STEPS ; 3
|
|
lda MAX_STEPS ; 3
|
|
nop ; 2
|
|
jmp done_moving_ft ; 3+7
|
|
|
|
done_moving_first:
|
|
; 7 cycles
|
|
lda MAX_STEPS ; 3
|
|
nop ; 2
|
|
nop ; 2
|
|
done_moving_second:
|
|
; 12 cycles
|
|
lda MAX_STEPS ; 3
|
|
nop ; 2
|
|
lda MAX_STEPS ; 3
|
|
nop ; 2
|
|
nop ; 2
|
|
done_moving_third:
|
|
; 20 cycles
|
|
lda MAX_STEPS ; 3
|
|
lda MAX_STEPS ; 3
|
|
lda MAX_STEPS ; 3
|
|
lda MAX_STEPS ; 3
|
|
lda MAX_STEPS ; 3
|
|
lda MAX_STEPS ; 3
|
|
nop ; 2
|
|
done_moving:
|
|
lda MAX_STEPS ; 3
|
|
sta CURRENT_STEP ; 3
|
|
;============
|
|
; 6
|
|
done_bounds_checking:
|
|
|
|
|
|
;=======================================================================
|
|
; draw rocket
|
|
;=======================================================================
|
|
;
|
|
; cs!=mx 9+15+258+258+3+10+258+258+9+7+11 = 1096
|
|
; cs==mx 9+ + + + +10+258+258+9+7+11 = 562 (need 534)
|
|
draw_rocket:
|
|
|
|
lda CURRENT_STEP ; 3
|
|
cmp MAX_STEPS ; 3
|
|
beq skip_drawing_rocket ; 3
|
|
;===========
|
|
; 9
|
|
|
|
; set hcolor to proper white (3 or 7)
|
|
;-1
|
|
clc ; 2
|
|
lda COLOR_GROUP ; 3
|
|
adc #3 ; 2
|
|
tax ; 2
|
|
lda colortbl,X ; get color from table ; 4+
|
|
sta HGR_COLOR ; 3
|
|
;============
|
|
; 15
|
|
; HPLOT X,Y: X= (y,x), Y=a
|
|
|
|
ldx X_OLD ; 3
|
|
lda Y_OLD ; 3
|
|
ldy #0 ; 2
|
|
jsr hplot0 ; hplot(x_old,y_old); ;6+244
|
|
;=============
|
|
; 258
|
|
|
|
; HPLOT TO X,Y X=(x,a), y=Y
|
|
ldx XPOS_L ; 3
|
|
ldy #0 ; 2
|
|
lda YPOS_H ; 3
|
|
jsr hplot0 ;6+244
|
|
;=============
|
|
; 258
|
|
|
|
; lda XPOS_L ; 3
|
|
; ldx #0 ; 2
|
|
; ldy YPOS_H ; 3
|
|
; jsr hglin ; hplot_to(xpos_l,ypos_h); ;?????
|
|
|
|
|
|
jmp erase_rocket ; 3
|
|
|
|
skip_drawing_rocket:
|
|
; Try X=7 Y=13 cycles=534
|
|
ldy #13 ; 2
|
|
sdloop1:ldx #7 ; 2
|
|
sdloop2:dex ; 2
|
|
bne sdloop2 ; 2nt/3
|
|
dey ; 2
|
|
bne sdloop1 ; 2nt/3
|
|
|
|
erase_rocket:
|
|
; erase with proper color black (0 or 4)
|
|
|
|
ldx COLOR_GROUP ; 3
|
|
lda colortbl,X ; get color from table ; 4+
|
|
sta HGR_COLOR ; 3
|
|
;===========
|
|
; 10
|
|
; HPLOT X,Y: X= (y,x), Y=a
|
|
|
|
ldx X_OLDER ; 3
|
|
lda Y_OLDER ; 3
|
|
ldy #0 ; 2
|
|
jsr hplot0 ; hplot(x_old,y_old); ; 6+244
|
|
;============
|
|
; 258
|
|
|
|
; HPLOT TO X,Y X=(x,a), y=Y
|
|
|
|
ldx X_OLD ; 3
|
|
ldy #0 ; 2
|
|
lda Y_OLD ; 3
|
|
jsr hplot0 ;6+244
|
|
;=============
|
|
; 258
|
|
; lda X_OLD
|
|
; ldx #0
|
|
; ldy Y_OLD
|
|
; jsr hglin ; hplot_to(x_old,y_old);
|
|
|
|
done_with_loop:
|
|
|
|
lda CURRENT_STEP ; 3
|
|
cmp MAX_STEPS ; 3
|
|
bne not_done_with_launch ; 3
|
|
;=============
|
|
; 9
|
|
|
|
;-1
|
|
lda #STATE_START_EXPLOSION ; 2
|
|
sta STATE ; 3
|
|
jmp not_done_with_launch2 ; 3
|
|
;==========
|
|
; 7
|
|
|
|
not_done_with_launch:
|
|
lda #STATE_STALL_ROCKET ; 2
|
|
sta STATE ; 3
|
|
nop ; 2
|
|
;==========
|
|
; 7
|
|
not_done_with_launch2:
|
|
|
|
inc CURRENT_STEP ; 5
|
|
rts ; 6
|
|
;===========
|
|
; 11
|
|
|
|
.align $100
|
|
|
|
;======================================================================
|
|
; Start explosion near x_old, y_old
|
|
;======================================================================
|
|
; cycles = 67+16+63+16+258+20 = 440
|
|
;
|
|
|
|
start_explosion:
|
|
|
|
; Set X position
|
|
|
|
lda #0 ; 2
|
|
sta XPOS_H ; 3
|
|
|
|
jsr random16 ; 6+42
|
|
lda SEEDL ; 3
|
|
and #$f ; 0..15 ; 2
|
|
sec ; 2
|
|
sbc #8 ; -8..7 ; 2
|
|
clc ; 2
|
|
bmi signextend_neg ; 3
|
|
;============
|
|
; 67
|
|
|
|
;-1
|
|
adc X_OLD ; 3
|
|
sta XPOS_L ; xpos=x_old+(random()%16)-8; x +/- 8 ; 3
|
|
|
|
lda #0 ; 2
|
|
adc XPOS_H ; 3
|
|
sta XPOS_H ; 3
|
|
|
|
jmp exp_sub_done ; 3
|
|
;===========
|
|
; 16
|
|
signextend_neg:
|
|
|
|
adc X_OLD ; 3
|
|
sta XPOS_L ; xpos=x_old+(random()%16)-8; x +/- 8 ; 3
|
|
|
|
lda #$ff ; 2
|
|
adc XPOS_H ; 3
|
|
sta XPOS_H ; 3
|
|
nop ; 2
|
|
;===========
|
|
; 16
|
|
|
|
exp_sub_done:
|
|
|
|
; set Y position
|
|
|
|
jsr random16 ; 6+42
|
|
lda SEEDL ; 3
|
|
and #$f ; 0..15 ; 2
|
|
sec ; 2
|
|
sbc #8 ; -8..7 ; 2
|
|
adc Y_OLD ; 3
|
|
sta YPOS_H ; ypos_h=y_old+(random()%16)-8; y +/- 8 ; 3
|
|
;============
|
|
; 63
|
|
|
|
; draw white (with fringes)
|
|
|
|
lda COLOR_GROUP ; 3
|
|
clc ; 2
|
|
adc #$3 ; 2
|
|
tax ; 2
|
|
lda colortbl,X ; get color from table ; 4+
|
|
sta HGR_COLOR ; 3
|
|
;===========
|
|
; 16
|
|
|
|
; hplot(xpos,ypos_h); draw at center of explosion
|
|
|
|
; HPLOT X,Y: X= (y,x), Y=a
|
|
|
|
ldx XPOS_L ; 3
|
|
lda YPOS_H ; 3
|
|
ldy #0 ; never above 255 ; 2
|
|
jsr hplot0 ; hplot(x_old,y_old); ; 6+244
|
|
;==============
|
|
; 258
|
|
; Make sound and ready explosion
|
|
|
|
sound3:
|
|
bit SPEAKER ; 4
|
|
|
|
ldy #1 ; 2
|
|
sty TEMPY ; save Y ; 3
|
|
|
|
; move to continue explosion
|
|
lda #STATE_CONTINUE_EXPLOSION ; 2
|
|
|
|
sta STATE ; 3
|
|
|
|
rts ; 6
|
|
;=============
|
|
; 20
|
|
|
|
;==========================================================================
|
|
; Continue Explosion
|
|
;==========================================================================
|
|
;
|
|
; cycles cpy!=9 : 8+2233+2227+13+5 = 4486
|
|
; cpy==9 : 8+ +2227+13+62 = 2310 waste 2176
|
|
|
|
continue_explosion:
|
|
ldy TEMPY ; 3
|
|
|
|
;================================
|
|
; Draw spreading dots in white
|
|
|
|
cpy #9 ; 2
|
|
beq explosion_erase_waste ; 3
|
|
;===========
|
|
; 8
|
|
|
|
|
|
; -1
|
|
; hcolor_equals(color_group+3);
|
|
lda COLOR_GROUP ; 3
|
|
clc ; 2
|
|
adc #$3 ; 2
|
|
tax ; 2
|
|
lda colortbl,X ; get color from table ; 4+
|
|
sta HGR_COLOR ; 3
|
|
|
|
ldx TEMPY ; 3
|
|
stx OFFSET ; 3
|
|
|
|
jsr explosion ; 6+2203
|
|
|
|
jmp explosion_erase ; 3
|
|
;============
|
|
; 2233
|
|
explosion_erase_waste:
|
|
; waste 2176-4 = 2172
|
|
|
|
sound2:
|
|
; bit SPEAKER ; 4
|
|
nop
|
|
nop
|
|
|
|
; Try X=47 Y=9 cycles=2170 R2
|
|
|
|
nop ; 2
|
|
|
|
ldy #9 ; 2
|
|
eeloop1:ldx #47 ; 2
|
|
eeloop2:dex ; 2
|
|
bne eeloop2 ; 2nt/3
|
|
dey ; 2
|
|
bne eeloop1 ; 2nt/3
|
|
|
|
|
|
|
|
explosion_erase:
|
|
;======================
|
|
; erase old
|
|
|
|
; erase with proper color black (0 or 4)
|
|
|
|
ldx COLOR_GROUP ; 3
|
|
lda colortbl,X ; get color from table ; 4+
|
|
sta HGR_COLOR ; 3
|
|
|
|
ldx TEMPY ; 3
|
|
dex ; 2
|
|
stx OFFSET ; 3
|
|
|
|
jsr explosion ; 6+2203
|
|
;==============
|
|
; 2227
|
|
done_with_explosion:
|
|
|
|
; lda #$c0 ;
|
|
; jsr WAIT ;
|
|
|
|
inc TEMPY ; 5
|
|
lda TEMPY ; 3
|
|
cmp #10 ; 2
|
|
beq explosion_done ; 3
|
|
;=============
|
|
; 13
|
|
|
|
; -1
|
|
rts ; 6
|
|
|
|
explosion_done:
|
|
;==================================
|
|
; randomly draw more explosions
|
|
;==================================
|
|
jsr random16 ; 6+42
|
|
lda SEEDL ; 3
|
|
and #$4 ; 2
|
|
sta STATE ; 3
|
|
|
|
; if 0, then move to state 0 (start over)
|
|
; if 1, then move to state 4 (new random explosion)
|
|
|
|
rts ; 6
|
|
;============
|
|
; 62
|
|
|
|
|
|
.align $100
|
|
|
|
;===============================
|
|
; Draw explosion rays
|
|
;===============================
|
|
;
|
|
; Note: the western pixels don't do the full 16-bit math
|
|
; as currently it's not possible for those to overflow 256
|
|
;
|
|
; cycles = 275+275+270+270+272+278+278+279+6=2203
|
|
|
|
explosion:
|
|
|
|
; HPLOT X,Y: X= (y,x), Y=a
|
|
|
|
; Southeast pixel
|
|
clc ; 2
|
|
lda XPOS_L ; 3
|
|
adc OFFSET ; 3
|
|
tax ; 2
|
|
lda XPOS_H ; 3
|
|
adc #0 ; 2
|
|
tay ; 2
|
|
clc ; 2
|
|
lda YPOS_H ; 3
|
|
adc OFFSET ; 3
|
|
jsr hplot0 ; hplot(xpos+o,ypos_h+o); ; 6+244
|
|
;==============
|
|
; 275
|
|
|
|
; Northeast Pixel
|
|
clc ; 2
|
|
lda XPOS_L ; 3
|
|
adc OFFSET ; 3
|
|
tax ; 2
|
|
lda XPOS_H ; 3
|
|
adc #0 ; 2
|
|
tay ; 2
|
|
sec ; 2
|
|
lda YPOS_H ; 3
|
|
sbc OFFSET ; 3
|
|
jsr hplot0 ; hplot(xpos+o,ypos_h-o); ; 6+244
|
|
;==============
|
|
; 275
|
|
|
|
; Northwest Pixel
|
|
sec ; 2
|
|
lda XPOS_L ; 3
|
|
sbc OFFSET ; 3
|
|
tax ; 2
|
|
ldy #0 ; 2
|
|
sec ; 2
|
|
lda YPOS_H ; 3
|
|
sbc OFFSET ; 3
|
|
jsr hplot0 ; hplot(xpos-o,ypos_h-o); NW ; 6+244
|
|
;==============
|
|
; 270
|
|
|
|
; Southwest Pixel
|
|
sec ; 2
|
|
lda XPOS_L ; 3
|
|
sbc OFFSET ; 3
|
|
tax ; 2
|
|
ldy #0 ; 2
|
|
clc ; 2
|
|
lda YPOS_H ; 3
|
|
adc OFFSET ; 3
|
|
jsr hplot0 ; hplot(xpos-o,ypos_h+o); SW ; 6+244
|
|
;=============
|
|
; 270
|
|
|
|
; HPLOT X,Y: X= (y,x), Y=a
|
|
|
|
; South Pixel
|
|
ldx XPOS_L ; 3
|
|
ldy XPOS_H ; 3
|
|
clc ; 2
|
|
lda OFFSET ; 3
|
|
adc OFFSET ; 3
|
|
adc OFFSET ; 3
|
|
lsr ; 2
|
|
adc YPOS_H ; 3
|
|
jsr hplot0 ; hplot(xpos,ypos_h+(o*1.5)); S ; 6+244
|
|
;=============
|
|
; 272
|
|
|
|
; North Pixel
|
|
ldx XPOS_L ; 3
|
|
ldy XPOS_H ; 3
|
|
clc ; O O*1.5 NEG ; 2
|
|
lda OFFSET ; 0 = 0 0 ; 3
|
|
adc OFFSET ; 1 = 1 -1 ; 3
|
|
adc OFFSET ; 2 = 3 -3 ; 3
|
|
lsr ; 3 = 4 -4 ; 2
|
|
eor #$FF ; 4 = 6 -6 ; 2
|
|
clc ; 2
|
|
adc #1 ; 2
|
|
adc YPOS_H ; 3
|
|
jsr hplot0 ; hplot(xpos,ypos_h-(o*1.5)); N ; 6+244
|
|
;==============
|
|
; 278
|
|
|
|
; HPLOT X,Y: X= (y,x), Y=a
|
|
|
|
; East Pixel
|
|
clc ; 2
|
|
lda OFFSET ; 3
|
|
adc OFFSET ; 3
|
|
adc OFFSET ; 3
|
|
lsr ; 2
|
|
adc XPOS_L ; 3
|
|
tax ; 2
|
|
lda #0 ; 2
|
|
adc XPOS_H ; 3
|
|
tay ; 2
|
|
lda YPOS_H ; 3
|
|
jsr hplot0 ; hplot(xpos+(o*1.5),ypos_h); E ; 6+244
|
|
;==============
|
|
; 278
|
|
|
|
; West Pixel
|
|
clc ; O O*1.5 NEG ; 2
|
|
lda OFFSET ; 0 = 0 0 ; 3
|
|
adc OFFSET ; 1 = 1 -1 ; 3
|
|
adc OFFSET ; 2 = 3 -3 ; 3
|
|
lsr ; 3 = 4 -4 ; 2
|
|
eor #$FF ; 4 = 6 -6 ; 2
|
|
clc ; 2
|
|
adc #1 ; 2
|
|
adc XPOS_L ; 3
|
|
tax ; 2
|
|
ldy #0 ; 2
|
|
lda YPOS_H ; 3
|
|
jsr hplot0 ; hplot(xpos-(o*1.5),ypos_h); W ; 6+244
|
|
;==============
|
|
; 279
|
|
|
|
rts ; 6
|
|
|
|
|
|
|
|
;=========================================================================
|
|
; Draw the stars
|
|
;=========================================================================
|
|
; 7+ 280X + 5
|
|
; 16 stars = 4492
|
|
|
|
|
|
.align $100
|
|
draw_stars:
|
|
; HCOLOR = 3, white (though they are drawn purple)
|
|
lda #$7f ; 2
|
|
sta HGR_COLOR ; 3
|
|
ldy #0 ; 2
|
|
;===========
|
|
; 7
|
|
|
|
star_loop:
|
|
tya ; 2
|
|
pha ; 3
|
|
|
|
; HPLOT X,Y
|
|
; X= (y,x), Y=a
|
|
|
|
ldx stars,Y ; 4+
|
|
lda stars+1,Y ; 4+
|
|
ldy #0 ; 2
|
|
|
|
jsr hplot0 ;6+244
|
|
|
|
pla ; 4
|
|
tay ; 2
|
|
|
|
iny ; 2
|
|
iny ; 2
|
|
cpy #NUMSTARS*2 ; 2
|
|
|
|
bne star_loop ; 3
|
|
;============
|
|
; 279
|
|
|
|
; -1
|
|
rts ; 6
|
|
|
|
stars: ; even x so they are purple
|
|
.byte 28,107, 108, 88, 126, 88, 136, 95
|
|
.byte 150,108, 148,120, 172,124, 180,109
|
|
.byte 216, 21, 164, 40, 124, 18, 60, 12
|
|
.byte 240,124, 94,125, 12, 22, 216,116
|
|
|