Source code in the s-basic programming language

$constant true  =  0FFFFH
$constant false =  0

function half(n = integer) = integer
end = n / 2

function twice(n = integer) = integer
end = n + n

rem - return true (-1) if n is even, otherwise false 
function even(n = integer) = integer
var one = integer  
one = 1   rem - only variables are compared bitwise
end = ((n and one) = 0)

rem - return i * j, optionally showing steps
function ethiopian(i, j, show = integer) = integer
  var p = integer
  p = 0
  while i >= 1 do
    begin
      if even(i) then
        begin
          if show then print i;" ---";j
        end
      else
        begin
          if show then print i;"    ";j;"+"
          p = p + j
        end
      i = half(i)
      j = twice(j)
    end
  if show then 
    begin
      print "----------"
      print "     =";
    end
end = p

rem - exercise the function
print "Multiplying 17 times 34"
print ethiopian(17,34,true)

end