x3.bas

 set optimization noinlinedata

 dim ns0p = a
 dim jf = b
 dim p0x = c
 dim p0v = d

 player1:
 %11111110
 %01111100
 %00111000
 %00010000
 %00000000
 %00000000
 %00000000
 %00000000
end

 player0:
 %00000000
 %00000000
 %00000000
 %00000000
 %00000000
 %00011000
 %10111101
 %01100110
end

  player1x = 76 : player1y = 88
  player0x = 56 : p0x = 56 : player0y = 10
  ns0p = %00000111 : jf = 1 : p0v = 0

main

  if !collision(player0, missile1) then no_col

  rem bits in the table pointer ns0p correspond
  rem to the three copies and get masked out
  rem for a collision

  temp1 = missile1x - p0x
  if temp1 < 8 then ns0p = ns0p & %11111011 : goto update_p0
  if temp1 < 24 then ns0p = ns0p & %11111101 : goto update_p0
  if temp1 < 40 then ns0p = ns0p & %11111110 : goto update_p0
update_p0
  jf = 1 : missile1y = 0
  if !ns0p then p0v = 1 : ns0p = %00000111
no_col

  if joy0fire && jf then missile1x = player1x + 3 : missile1y = 80 : jf = 0
  if joy0left then if player1x > 8 then player1x = player1x - 1
  if joy0right then if player1x < 146 then player1x = player1x + 1

  if jf then skip_missile
  missile1y = missile1y - 1
  if !missile1y then jf = 1
skip_missile

  p0x = p0x + p0v
  if p0x < 10 || p0x >110 then p0v = 0 - p0v

  player0x = p0x + pos0[ns0p]

  NUSIZ0 = ns0[ns0p]
  NUSIZ1 = $10
  COLUP0 = $28
  COLUP1 = $20
  COLUBK = $00
  drawscreen

  goto main

 data ns0
 $20, $20, $20, $21, $20, $22, $21, $23
end

 data pos0
  $00, $20, $10, $10, $00, $00, $00, $00
end