dos33fsprogs/demos/d2/moving.s

117 lines
1.9 KiB
ArmAsm

; Moving
; moving, orange and green
; this is plotting
; sin(y/4-FRAME) + sin(x) + sin(x+frame)
; or at least I think so. Comment your code!
;================================
; Clear screen and setup graphics
;================================
moving:
lda #0
sta FRAME
;============================
; main loop
;============================
draw_moving:
inc FRAME
moving_size_smc:
lda #191 ; YY
create_yloop:
; HGR_Y (YY) is in A here
; ldx #39 ; X is don't care?
; ldy #0 ; Y is also don't care?
jsr HPOSN ; (Y,X),(A) (values stores in HGRX,XH,Y)
; restore values
lda HGR_Y ; YY in X
tax
calcsine_div4:
lsr ; YY/4
lsr ; 2
sec
sbc FRAME ; YY/4-FRAME
tay
lda sinetable,y ; A=SIN(YY/4-FRAME)
sta row_sum_smc+1
; ldx HGR_Y ; YY
ldy #39 ; XX
create_xloop:
;=====================
; critical inner loop
; every cycle here is 40x192 cycles
;=====================
clc
tya ; XX
adc FRAME ; XX+FRAME
tax
lda sinetable,X ; SIN(XX+FRAME)
adc sinetable,Y ; SIN(XX)+SIN(XX+FRAME) ; 4+
row_sum_smc:
adc #$dd ; row base value ; 2
; this is SIN(YY/4-FRAME)
lsr ; double colors ; 2
; also puts bit in carry
; which helps proper color gen
and #$7 ; 2
tax ; 2
colorlookup_smc:
lda colorlookup,X ; lookup in table ; 5
ror_nop_smc:
ror ; $6A/$EA ; 2
sta (GBASL),Y ; 6
lda ror_nop_smc ; toggle ror/nop ; 4
eor #$80 ; 2
sta ror_nop_smc ; 4
dey ; 2
bpl create_xloop ; 2/3
dec HGR_Y
lda HGR_Y
cmp #$ff ; blah want to draw line 0
bne create_yloop
jsr flip_page
lda FRAME
cmp #$1b ; NOTE: NEEDS TO BE ODD
bne draw_moving ; bra
; rts
;colorlookup:
;.byte $22,$aa,$ba,$ff,$ba,$aa,$22 ; use 00 from sinetable
;;.byte $00
;;.byte $11,$55,$5d,$7f,$5d,$55,$11 ; use 00 from sinetable
;;.byte $00
;sinetable_base:
;; this is actually (32*sin(x))
;.byte $00,$03,$06,$09,$0C,$0F,$11,$14
;.byte $16,$18,$1A,$1C,$1D,$1E,$1F,$1F
;.byte $20
;sinetable=$8000