mirror of
https://github.com/deater/dos33fsprogs.git
synced 2024-06-11 05:29:38 +00:00
156 lines
1.9 KiB
ArmAsm
156 lines
1.9 KiB
ArmAsm
; random scroll
|
|
|
|
; 125 bytes
|
|
|
|
|
|
; ***** *****
|
|
; ** **
|
|
; ** **
|
|
; ** **
|
|
; ** **
|
|
; ** **
|
|
; ***** *****
|
|
|
|
|
|
; by Vince `deater` Weaver
|
|
|
|
FULLGR = $C052
|
|
PAGE1 = $C054
|
|
PAGE2 = $C055
|
|
LORES = $C056 ; Enable LORES graphics
|
|
|
|
PLOT = $F800 ; PLOT AT Y,A (A colors output, Y preserved)
|
|
GBASCALC = $F847 ; Y in A, put addr in GBASL/GBASH
|
|
SETGR = $FB40
|
|
WAIT = $FCA8 ; delay 1/2(26+27A+5A^2) us
|
|
|
|
GBASL = $26
|
|
GBASH = $27
|
|
PAGE = $FE
|
|
LINE = $FF
|
|
|
|
diamond:
|
|
|
|
jsr SETGR
|
|
bit FULLGR
|
|
|
|
lda #$4 ; reset to beginning
|
|
sta PAGE
|
|
|
|
diamond_loop:
|
|
|
|
lda PAGE ; reset page smc
|
|
sta inner_loop_smc+2
|
|
|
|
lda #8 ; lines to count (*3=24)
|
|
sta LINE
|
|
|
|
;============================
|
|
; draw an interleaved line
|
|
|
|
line_loop:
|
|
ldx #119
|
|
|
|
screen_loop:
|
|
|
|
txa ; extrapolate Y from X
|
|
and #$7
|
|
tay
|
|
|
|
pattern_smc:
|
|
lda pattern1,Y
|
|
|
|
inner_loop_smc:
|
|
sta $400,X
|
|
|
|
dex
|
|
bpl screen_loop
|
|
|
|
;=================================
|
|
; move to next pattern
|
|
; assume we are in same 256 byte page (so high byte never change)
|
|
|
|
jsr scroll_pattern
|
|
|
|
; move to next line
|
|
|
|
clc
|
|
lda inner_loop_smc+1
|
|
adc #$80
|
|
sta inner_loop_smc+1 ; FIXME just inc if carry set
|
|
bcc noflo
|
|
inc inner_loop_smc+2
|
|
noflo:
|
|
|
|
dec LINE
|
|
bne line_loop
|
|
|
|
;=======================================
|
|
; done drawing frame
|
|
;=======================================
|
|
|
|
|
|
;======================
|
|
; draw box
|
|
|
|
ldx #16
|
|
boxloop:
|
|
txa
|
|
jsr GBASCALC
|
|
lda GBASH
|
|
clc
|
|
adc PAGE
|
|
sec
|
|
sbc #4
|
|
sta GBASH
|
|
|
|
lda #$FF ; white bar
|
|
ldy #30
|
|
draw_line_loop:
|
|
sta (GBASL),Y ; partway down screen
|
|
dey
|
|
cpy #10
|
|
bne draw_line_loop
|
|
|
|
dex
|
|
cpx #6
|
|
bne boxloop
|
|
|
|
|
|
;=========================
|
|
; scroll one line
|
|
|
|
jsr scroll_pattern
|
|
|
|
; switch page
|
|
lda PAGE
|
|
eor #$c
|
|
sta PAGE ; is 4 or 8
|
|
|
|
lsr
|
|
lsr ; now 0 or 1 (C is 1 or 0)
|
|
and #$1
|
|
tax
|
|
lda PAGE1,X
|
|
|
|
lda #200
|
|
jsr WAIT
|
|
|
|
; A is 0 after
|
|
|
|
beq diamond_loop
|
|
|
|
|
|
scroll_pattern:
|
|
clc
|
|
lda pattern_smc+1
|
|
adc #8
|
|
and #$1f
|
|
sta pattern_smc+1
|
|
rts
|
|
|
|
|
|
pattern1:
|
|
|
|
jmp diamond
|