XC=Basic Demo

const SCREEN = 1024
const RASTER = 53266
const BALL = 81
const SPACE = 32
const BACK = 53280
const COLLOC = 54272

x = 1
y = 1
dx = 1
dy = 1
m = 0
posy=12
posx=0
dposy=1
dposx=1
colorch=0
xx=0
dxx=1

goto start

origin $1000
incbin "Nightshift1.sid"

proc start_music
  asm "  sei"
  doke $314, @irq_routine
  poke $d011, $1b
  poke $d012, $e4
  poke $dc0d, %01111111
  poke $d01a, %00000001
  poke $d019, %00000001
  asm "
    lda #$00
    jsr $1000
    cli"
  return

  irq_routine:
    asm "
    lda #$01
    sta $d019
    jsr $1003
    asl $d019
    jmp $ea31"
endproc


start:
print "{CLR}"

call start_music

for colorch=0to1000:pokecolorch+SCREEN+COLLOC,7:nextcolorch

main:

  charat x, y, BALL
  gosub wait_frame
  charat x, y, SPACE

  textat xx,posy,  "xc=basic demo"
  textat xx,posy-1,"             "
  textat xx,posy+1,"             "
  posy=posy+dposy
  ifposy>12thendposy=-1
  ifposy<1 thendposy=1
  textat posx,24," by felix "
  i=1
  repeat
  pokeSCREEN+24*40+posx+i,peek(SCREEN+24*40+posx+i)+128
  inci
  untili=9
  posx=posx+dposx
  ifposx+5>x thendposx=-1
  ifposx+4<x thendposx=1
  ifposx<-1thenposx=-1
  ifposx>31thenposx=31

  if x = 0 then dx = 1 : poke BACK, m:xx=xx+dxx
  if x = 39 then dx = -1 : poke BACK, m:xx=xx+dxx
  if y = 0 then dy = 1 : poke BACK, m:xx=xx+dxx
  if y = 23 then dy = -1:poke BACK, m:xx=xx+dxx
  inc m
  if m > 255 then m=0


  x = x + dx
  y = y + dy

  if peek(SCREEN+x+40*y+1)<> SPACE then dx =-1
  if peek(SCREEN+x+40*y-1)<> SPACE then dx =1
  if peek(SCREEN+x+40*y+40)<> SPACE then dy =-1
  if peek(SCREEN+x+40*y-40)<> SPACE then dy =1

  ifxx>26thendxx=-1
  ifxx<1thendxx=1

goto main

wait_frame:
  if peek(RASTER) < 250 then goto wait_frame
return