nanoWarrior #03

The latest issue of nanoWarrior has finally been completed, containing articles by John Metcalf, German Labarga and me. Check it out for yourself here:

http://corewar.co.uk/nw/nw03.txt

Neo's Mini Challenge - Roy's Idea

Roy suggested a tricky extension to Neo's Mini Challenge in rec.games.corewar:

Lets try to find a solution for this gate:
djn.f #0,>-5
(I haven't got one yet)

It appears a one instruction solution isn't possible. However, 5 players found a solution in two instructions.  Congratulations to Ilmari, John, Rashnok, Roy and me! Also, well done to German and Lukasz who also discovered solutions, albeit slightly longer.

I discovered a five line imp:

imp mov.i #4,   *1
    mov.i #4,   *1
    mov.i #4,   *1
    mov.i #4,   *1
    mov.i #4,   *1

By adding a loop, I managed to reduce the initial size to two instructions:

imp mov.i #4,   *1
    djn.a imp,  #0

John and Rashnok discovered the same 3 line imp and used a loop to reduce the size. Ilmari discovered a 2 line imp. Roy wrote a program to find 58 solutions by brute force!

Full details are on Neo's page for the Harmless Overrun Mini Challenge.

Thoughts on Corewar...

Thoughts on Corewar is John Metcalf's Redcode programming blog, hosted at http://impomatic.blogspot.com. Since John's blog was last reviewed, both the name and design have changed.

The standard template has gone and the sidebar now contains a selection of useful rss feeds, including the latest posts from rec.games.corewar and the most recent additions to the infinite nano and tiny hills.

The most interesting recent posts have been about Semaphores in Redcode, which provide a means of implementing mutual exclusing in Corewar.

What I liked:

• Covers advanced programming topics
• The feeds make it easy to keep up-to-date

Room for improvement:

• More comments on the code would be handy