Article 2421 of rec.games.corewar:
Newsgroups: rec.games.corewar
Path: hellgate.utah.edu!dog.ee.lbl.gov!agate!howland.reston.ans.net!paladin.american.edu!darwin.sura.net!news.Vanderbilt.Edu!stst
From: stst@vuse.vanderbilt.edu (Stefan Strack)
Subject: Re: MNCT Lives!
Message-ID: <1994Feb1.032132.14279@news.vanderbilt.edu>
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Organization: Vanderbilt University School of Engineering, Nashville, TN, USA
References: <2ijsa2$rqg@agate.berkeley.edu>
Date: Tue, 1 Feb 1994 03:21:32 GMT
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In article <2ijsa2$rqg@agate.berkeley.edu> mconst@soda.berkeley.edu (Michael Constant) writes:
>Due to popular request (3 letters!), MNCT has returned!  Round 3 was where I
>left off, I think.  Just to refresh your memory, the rules for round 3 are:
>
>  Style:  Standard round-robin (each entry fights each other entry)
>  Standard:  94
>  Coresize:  unknown (that is, your program must function in a variety of
>             coresizes) but always < 64K

What about max. warrior length, max. processes, and, most importantly
cycles-until-tie? Is cycles-until-tie going to scale with coresize (e.g.
10*coresize) or remain fixed? Remember that the fastest complete core-clear
takes 2*coresize cycles.

Also, are you going to run round-robins for more than one coresize?

>BTW, since this round will incorporate large coresizes, this might be a good
>time for me to mention, once again, my optima calculator which handles
>coresize up to 64K.  [....]

Yes, but how is this going to do us any good if we don't know the coresize
beforehand :-) (this might be a good time for me to mention that you need
the 32-bit pMARS executables (pmars04g.zip) for the large coresize)

Things a warrior in a core of unknown dimensions might like to know are 
what divisors coresize has (to calculate imp-steps, self-avoiding bomb/scan
patterns, etc.) and perhaps the approximate size of core (to determine, e.g,
the best number of mini-bombers to launch).

To find out whether the current coresize is divisible by a certain number is
very straightforward in redcode'94:

DIVISOR	equ 5 

	org test

a	dat #-DIVISOR		; if coresize is divisible, so is this
test	mod #DIVISOR,a
	jmz divisible,a
	jmp not_divisible

The code below tries to get an idea of how large the core is by binary
subdivision. This is a reasonable compromise between speed (40 cycles in
a core of 8000) and accuracy (within a power of 2):

;redcode-94
;name sizer
;strategy Get an idea how large core is (within a power of 2)

        org sizer

cs      dat #-1         ;This is coresize-1
sizer   div #2,cs
        add #1,case
        jmn sizer,cs
case    jmp @case       ;jump somewhere depending on coresize

;trace on
ge1     jmp 0           ;core=  1-2  (we would jump to somewhere useful here)
ge3     jmp 0           ;       3-4
ge5     jmp 0           ;       5-8
ge9     jmp 0           ;       9-16
ge17    jmp 0           ;       17-32
ge33    jmp 0           ;       33-64
ge65    jmp 0           ;       65-128
ge129   jmp 0           ;       129-256
ge257   jmp 0           ;       257-512
ge513   jmp 0           ;       513-1024
ge1025  jmp 0           ;       1025-2048
ge2049  jmp 0           ;       2049-4096
ge4097  jmp 0           ;       4097-8192
ge8193  jmp 0           ;       8193-16384
ge16385 jmp 0           ;       16385-32768
ge32769 jmp 0           ;       32769-65536

(actually, this is the first time I find mul/div/mod really useful)

>                      - Michael Constant

Looking forward, Michael!

-Stefan (stst@vuse.vanderbilt.edu)