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

105 lines
1.1 KiB
ArmAsm

GBASL = $26
GBASH = $27
HGRPAGE = $E6
YPOS = $FD
LINE = $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
sta $C055 ; set page2
lda #$20
sta HGRPAGE
bit_rain:
; blue
lda #$0
sta COLOR
bit_rain_smc:
lda #100
sta YPOS
jsr draw_raster_bit
; red
lda #$8
sta COLOR
bit_rain2_smc:
lda #50
sta YPOS
jsr draw_raster_bit
lda bit_rain_smc+1
clc
adc #1
and #$7f
sta bit_rain_smc+1
lda bit_rain2_smc+1
clc
adc #1
and #$7f
sta bit_rain2_smc+1
jmp bit_rain
;=========================
; draw line of color in COLOR
;=========================
draw_raster_bit:
ldx #0
stx LINE
draw_raster_bit_loop:
ldx #0
ldy #0
lda YPOS
jsr HPOSN
clc
lda LINE
adc COLOR
tax
lda color_table,X
ldy #0
inside_loop:
sta (GBASL),Y
iny
iny
cpy #40
bne inside_loop
inc YPOS
inc LINE
ldx LINE
cpx #9
bne draw_raster_bit_loop
rts
color_table:
.byte $0
.byte $1,$3,$B,$F,$B,$3,$1,$0
.byte $8,$9,$D,$F,$D,$9,$8,$0