// readport

modulo()

int0()
  x = readport(10)   // sine
  print(x)
  x = readport(11)   // square wave
  print(x)
  x = readport(12)   // 31-bit random num
  x = modulo(x/2,100) 
  print(x)
  x = readport(13)   // master clock
  print(x)

modulo(x,y)
  asm("pop sp r2")
  asm("pop sp r1")
  asm("mod r1 r1 r2")
  return x

main()
  settimer0(100)
  while(1)
    doze()
