nano papers: ghoulish and Apis Mellifera

Here are a couple of nano paper/clear I've been playing with recently using a mov.i #1,<1 anti-imp clear.

;redcode-nano
;name ghoulish
;author S.Fernandes
;strategy paper/clear
;assert CORESIZE == 80

pstep   equ     -39
cpos    equ     -18
dpos    equ     27

paper   spl     #-21        ,    <-32
        mov     }paper-1    ,    }pboot
        mov.i   #1          ,    <1
pboot   spl     <pstep      ,    cpos
        djn.f   paper+1     ,    <dpos
        end

;redcode-nano
;name Apis Mellifera
;author S.Fernandes
;strategy paper/clear
;assert CORESIZE == 80

pstep   equ     -22
cpos    equ     -18
dpos    equ     -8

paper   spl     #0          ,    <33
        mov     }paper      ,    }pboot
pboot   spl     <pstep      ,    <-16
        mov.i   #1          ,    <1
        djn     paper+1     ,    #dpos
        end

Redcode Forth

Redcode Forth is an interpreter for a 36 word subset of the Forth programming language. I don't know much about Forth, but fortunately the interpreter is supplied with a summary of the instruction set and a step-by-step example.

The interpreter uses a new Redcode instruction to display text, sts. I wonder if John is also planning to support ARES which has a different system for i/o?

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.

Neo's Mini Challenge - The Results

Neo's Mini Challenge is over and the results are in. Seven players entered, 6 of who discovered an optimal solution - 1 line, 1 process, 100% ties.

Neo and I entered the following code:

mov }0, }1

Ilmari and John entered this:

mov.i #1, *1

While Roy and Rashnok used a variation on the above:

mov.i #1, }1

Finally, mjp entered code which expands to a 6 line imp:

mov 2, @1
djn -1, #6
mov 0, >6

Roy suggested an interesting alternative which Neo will hopefully adopt as the next challenge.