dos33fsprogs/ootw/gr_pageflip.s
Vince Weaver ac18cfd838 ootw: add another demake
why why why
2019-01-13 01:10:44 -05:00

25 lines
503 B
ArmAsm

;==========
; page_flip
;==========
page_flip:
lda DISP_PAGE ; 3
beq page_flip_show_1 ; 2nt/3
page_flip_show_0:
bit PAGE0 ; 4
lda #4 ; 2
sta DRAW_PAGE ; DRAW_PAGE=1 ; 3
lda #0 ; 2
sta DISP_PAGE ; DISP_PAGE=0 ; 3
rts ; 6
page_flip_show_1:
bit PAGE1 ; 4
sta DRAW_PAGE ; DRAW_PAGE=0 ; 3
lda #1 ; 2
sta DISP_PAGE ; DISP_PAGE=1 ; 3
rts ; 6
;====================
; DISP_PAGE=0 26
; DISP_PAGE=1 24