Source code in the icon programming language

procedure main(arglist)
while ethiopian(integer(get(arglist)),integer(get(arglist)))  # multiply successive pairs of command line arguments
end

procedure ethiopian(i,j)                                      # recursive Ethiopian multiplication
return ( if not even(i) then j                                # this exploits that icon control expressions return values
         else 0 ) + 
       ( if i ~= 0 then ethiopian(halve(i),double(j)) 
         else 0 )
end   

procedure double(i)
return i * 2
end

procedure halve(i)
return i / 2
end

procedure even(i)
return ( i % 2 = 0, i )
end


procedure ethiopian(i,j)  # iterative tutor
local p,w
w := *j+3
write("Ethiopian Multiplication of ",i," * ",j)

p := 0
until i = 0 do {
   writes(right(i,w),right(j,w))
   if not even(i) then {
      p +:= j
      write(" add")
      }
   else write(" discard")
   i := halve(i)
   j := double(j)
   }
write(right("=",w),right(p,w))
return p
end