dos33fsprogs/demos/mode7_demo/gr_fast_clear.s

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2018-12-30 06:03:07 +00:00
clear_screens:
;===================================
; Clear top/bottom of page 0
;===================================
lda #$0
sta DRAW_PAGE
jsr clear_top
jsr clear_bottom
;===================================
; Clear top/bottom of page 1
;===================================
lda #$4
sta DRAW_PAGE
jsr clear_top
jsr clear_bottom
rts
clear_bottoms:
;===================================
; Clear bottom of page 0
;===================================
lda #$0
sta DRAW_PAGE
jsr clear_bottom
;===================================
; Clear bottom of page 1
;===================================
lda #$4
sta DRAW_PAGE
jsr clear_bottom
rts
;=========================================================
; clear_top
;=========================================================
; clear DRAW_PAGE
; original = 14,558 cycles(?) 15ms, 70Hz
; OPTIMIZED MAX (page0,48rows): 45*120+4+6 = 5410 = 5.4ms 185Hz
; (pageX,40rows): 50*120+4+6 = 6010 = 6.0ms 166Hz
; 50*120+4+6+37 = 6055 = 6.0ms 166Hz
clear_top:
lda #0 ; 2
clear_top_a:
sta COLOR ; 3
clc ; 2
lda DRAW_PAGE ; 3
adc #4 ; 2
sta __ctf+2 ; 3
sta __ctf+5 ; 3
adc #1 ; 2
sta __ctf+8 ; 3
sta __ctf+11 ; 3
adc #1 ; 2
sta __ctf2+2 ; 3
sta __ctf2+5 ; 3
adc #1 ; 2
sta __ctf2+8 ; 3
sta __ctf2+11 ; 3
ldy #120 ; 2
lda COLOR ; 3
clear_top_fast_loop:
__ctf:
sta $400,Y ; 5
sta $480,Y ; 5
sta $500,Y ; 5
sta $580,Y ; 5
cpy #80 ; 2
bpl no_draw_bottom ; 2nt/3
__ctf2:
sta $600,Y ; 5
sta $680,Y ; 5
sta $700,Y ; 5
sta $780,Y ; 5
no_draw_bottom:
dey ; 2
bpl clear_top_fast_loop ; 2nt/3
rts ; 6
;=========================================================
; clear_bottom
;=========================================================
; clear bottom of draw page
clear_bottom:
clc ; 2
lda DRAW_PAGE ; 3
adc #6 ; 2
sta __cbf2+2 ; 3
sta __cbf2+5 ; 3
adc #1 ; 2
sta __cbf2+8 ; 3
sta __cbf2+11 ; 3
ldy #120 ; 2
lda #$a0 ; Normal Space ; 2
clear_bottom_fast_loop:
__cbf2:
sta $600,Y ; 5
sta $680,Y ; 5
sta $700,Y ; 5
sta $780,Y ; 5
dey ; 2
cpy #80 ; 2
bpl clear_bottom_fast_loop ; 2nt/3
rts ; 6
clear_screens_notext:
;===================================
; Clear top/bottom of page 0
;===================================
lda #$0
sta DRAW_PAGE
jsr clear_all
;===================================
; Clear top/bottom of page 1
;===================================
lda #$4
sta DRAW_PAGE
jsr clear_all
rts
;=========================================================
; clear_all
;=========================================================
; clear 48 rows
clear_all:
clc ; 2
lda DRAW_PAGE ; 3
adc #4 ; 2
sta __caf+2 ; 3
sta __caf+5 ; 3
adc #1 ; 2
sta __caf+8 ; 3
sta __caf+11 ; 3
adc #1 ; 2
sta __caf2+2 ; 3
sta __caf2+5 ; 3
adc #1 ; 2
sta __caf2+8 ; 3
sta __caf2+11 ; 3
ldy #120 ; 2
clear_all_color:
lda #0 ; 2
clear_all_fast_loop:
__caf:
sta $400,Y ; 5
sta $480,Y ; 5
sta $500,Y ; 5
sta $580,Y ; 5
__caf2:
sta $600,Y ; 5
sta $680,Y ; 5
sta $700,Y ; 5
sta $780,Y ; 5
dey ; 2
bpl clear_all_fast_loop ; 2nt/3
rts ; 6