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firework: time invariant launch

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This commit is contained in:
Vince Weaver 2018-09-10 16:06:21 -04:00
parent ca57701102
commit fd80493293
1 changed files with 44 additions and 17 deletions
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61
fireworks/fw.s
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@ -79,14 +79,16 @@ done_fireworks:
;===========================
; LAUNCH_FIREWORK
;===========================
; cycles=???
; cycles= 54+60+67+60+56+56+15+8+21+11 = 408
launch_firework:
jsr random16 ; 6+42
lda SEEDL ; 3
and #$4 ; 2
sta COLOR_GROUP ; HGR color group (0 PG or 4 BO) ; 4
sta COLOR_GROUP ; HGR color group (0 PG or 4 BO) ; 3
;============
; 54
jsr random16 ; 6+42
lda SEEDL ; 3
@ -94,6 +96,9 @@ launch_firework:
clc ; 2
adc #$1 ; 2
sta X_VELOCITY ; x velocity = 1..4 ; 3
;===========
; 60
jsr random16 ; 6+42
lda SEEDL ; 3
@ -104,6 +109,8 @@ launch_firework:
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
@ -111,37 +118,54 @@ launch_firework:
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 ; 3
sta XPOS_L ; base of 0..63 ; 3
;============
; 56
jsr random16 ; 6+42
lda SEEDL ; 3
and #$1 ; 2
beq right_hill ; 2
left_hill:
lda XPOS_L ; 3
clc ; 2
adc #24 ; 2
sta XPOS_L ; 24-88 (64) ; 3
beq right_hill ; 3
;============
; 56
left_hill: ;-1
lda X_VELOCITY ; nop ; 3
lda X_VELOCITY ; nop ; 3
lda X_VELOCITY ; nop ; 3
nop ; 2
lda #24 ; make it 24..87 ; 2
jmp done_hill ; 3
right_hill:
; 1
lda XPOS_L ; 3
clc ; 2
adc #191 ; 2
sta XPOS_L ; 191-255 (64) ; 3
;===========
; 15
right_hill:
lda X_VELOCITY ; 3
eor #$ff ; 2
sta X_VELOCITY ; 3
inc X_VELOCITY ; aim toward middle ; 5
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
@ -153,12 +177,15 @@ done_hill:
lda #1 ; 2
sta CURRENT_STEP ; 3
;===========
; 21
lda #1 ; 2
sta STATE ; move to launch ; 3
rts ; 6
;============
; 11
;===============