Addleq

Addleq is a Turing-complete OISC language invented by Oleg (thank r.e.s.), very similar to Subleq, with the exception that it uses addition operation instead of subtraction. However it is much harder to program in Addleq than in Subleq.

Because of similarity to Subleq, the exactly same assembly notation can be used.

Elementary operations
The following variable definitions can be useful . Z:0 dec:-1 inc:1 t1:0 t2:0 Z is zero and should not be changed, dec and inc are useful for decrementing and incrementing, t's are temporary variables.

If A has value and B is 0, then copying A to B as as simple as A B If B is not zero, it has to be known if it is greater or less than zero. It is possible to clear B, for example, in the following way. Suppose that B is not less than 0, then inc B dec B ?+3 Z Z ?-6 does the trick. Obviously there is a much faster solution (not presented here) which doubles negative unit and recursively builds a negative counterpart.

As in Subleq assembly ? signifies the address of the next memory cell. So the example above is the same as        inc B repeat: dec B do_smth_else Z Z repeat do_smth_else: ...

If B>0 than . Z:0 dec:-1 B:0 dec B ?+3 Z Z ?-6 which compiles into 0 -1 0 1 2 9 0 0 3

Input/Output
Input and output operations can be defined exactly as in Subleq with a specail address (-1). This program echos input: start: -1 x (-1) x (-1) # clear x       dec x start Z Z ?-6 . Z:0 dec:-1 x:0
 * 1) Echo

Hello, World!
"Hello world" program is a bit more complex. For dereferencing operation the same technique as in Subleq can be used. # Hello world! # output *p; dec a ?+3; Z Z ?-6 p a    a:1 (-1) # p++ inc p    # clear temps dec t1 ?+3; Z Z ?-6 dec t2 ?+3; Z Z ?-6 # t2=(-p+1) p t1    dec t1 ?+3 dec t2 ?-6 # check if p0 dec t ?+3; Z Z ?-6 b:1 t (-1) # output a    a:1 (-1) # p++ inc p    Z Z 0 . p:H Z:0 dec:-1 inc:1 t:0 . H:"Hello, World!\n\0"

How to run Addleq programs
Use sqasm.cpp to compile assembly program into the Addleq code. Then sqrun.cpp with the option (-a) to run the compiled code.

External resources

 * Addleq on Oleg Mazonka's site.