dos33fsprogs/dhgr/lots.s
2020-10-07 17:01:18 -04:00

77 lines
846 B
ArmAsm

GBASL = $26
GBASH = $27
HGRPAGE = $E6
YPOS = $FE
COLOR = $FF
HGR = $F3E2
HGR2 = $F3D8
HPOSN = $F411
raster:
jsr HGR
jsr HGR2
; sta $C050 ; set graphics
; sta $C057 ; set hires
; sta $C052 ; set fullscreen
sta $C05E ; set double hires
sta $C00D ; 80 column
sta $C001 ; 80 store
lda #$20
sta HGRPAGE
lda #0
sta YPOS
color_loop:
lda YPOS
and #$f
sta COLOR
asl
asl
asl
asl
ora COLOR
sta COLOR
lda YPOS
jsr draw_line_color
inc YPOS
lda YPOS
cmp #192
bne color_loop
forever:
jmp forever
;=========================
; draw line of color in COLOR
;=========================
draw_line_color:
ldx #0
ldy #0
jsr HPOSN
ldy #0
loop_it:
; set page2
sta $C055
lda COLOR
sta (GBASL),Y
cmp #$80
rol COLOR
; set page1
sta $C054
lda COLOR
sta (GBASL),Y
cmp #$80
rol COLOR
iny
cpy #40
bne loop_it
rts