Sections
Home
Hills
Infinite Hills
Tournaments
Software
Evolving
Optimizer
Community
Newsletter
Discussion
History
Sections
 
For Beginners
First Steps
FAQ
Guides
Lexicon
Benchmarks
For Beginners
> Home > The Corewar Newsletters > The '94 Warrior > Issue #4

March 16, 1994                                                        Issue #4
______________________________________________________________________________

This newletter covers the current status of the ICWS '94 Draft hills,
and also attempts to keep up with the latest ideas in how the new standard
will affect corewars in general.  I hope you enjoy it!

If you are unfamiliar with the '94 draft standard, you can learn more about
it by reading the FAQ for this newsgroup.  In addition, the program pMARS
includes a highly recommended tutorial on the new standard.  Feel free
to send me e-mail if you have any difficulty finding either of them, if you
need to have a corewar item mailed to you, or if you have any other questions.

The FAQ is available through anonymous FTP to rtfm.mit.edu, as
/pub/usenet/news.answers/games/corewar-faq.Z
______________________________________________________________________________

The ICWS '94 Draft Hill:

       Core size:	8000 instrucitons
   Max processes:	8000 per program
        Duration:	After 80,000 cycles, a tie is declared.
Max entry length:	100 instructions

The current ICWS '94 Draft hill:
 #  %W/ %L/ %T                      Name               Author   Score     Age
 1  46/ 31/ 23           Killer instinct         Anders Ivner     162       9
 2  42/ 23/ 34                     NC II       Wayne Sheppard     162      64
 3  41/ 25/ 35               Sphinx v5.1         W. Mintardjo     157      67
 4  37/ 22/ 42                    ttti94        nandor sieben     152      15
 5  46/ 42/ 12           Fire Storm v1.1         W. Mintardjo     151      70
 6  36/ 22/ 43                      ttti        nandor sieben     150      20
 7  38/ 26/ 36        JustTakingALookSee            J.Layland     150      63
 8  43/ 41/ 16            Sylvester v1.0     Brant D. Thomsen     145      46
 9  42/ 40/ 17              Request v2.0     Brant D. Thomsen     144       2
10  35/ 26/ 39                     Snake       Wayne Sheppard     144      19
11  41/ 39/ 20               Christopher       Steven Morrell     143       8
12  41/ 40/ 19            Fast Food v2.1     Brant D. Thomsen     142      22
13  41/ 42/ 16               Ntttgtstitd         Simon Hovell     141      10
14  43/ 45/ 13                    Rave 4        Stefan Strack     141       3
15  41/ 41/ 18       Beholder's Eye v1.7         W. Mintardjo     140      76
16  43/ 46/ 11                      Rave        Stefan Strack     140      47
17  41/ 43/ 16                      SJ-4            J.Layland     140      13
18  40/ 40/ 21                      tiny            J.Layland     140      44
19  42/ 46/ 12           Testing an Idea     Brant D. Thomsen     138       1
20  42/ 48/ 11                Impurge 94     Fredrik Ohrstrom     136       6

The '94 draft hill seems to be getting quite vicious lately.  There were
several attempts at the hill, but not very many made it.

(The program "Testing an Idea" is discussed in this issue's hint section.)
______________________________________________________________________________

th ICWS '94 Draft Experimental Hill:

       Core size:	55,440 instructions
   Max processes:	10,000 per program
        Duration:	After 500,000 cycles, a tie is declared.
Max entry length:	200 instructions

The current ICWS '94 Experimental hill:
 #  %W/ %L/ %T                      Name               Author   Score     Age
 1  53/ 12/ 35                    BigImp        Alex MacAulay     194      25
 2  52/ 17/ 30       Imperfection v1.0 X     Michael Constant     187      21
 3  60/ 34/  6            Rave 3 (55440)        Stefan Strack     185      36
 4  42/ 13/ 45                 Skimp 127              Jay Han     171       6
 5  54/ 42/  4           No Ties Allowed       Wayne Sheppard     166      41
 6  51/ 38/ 10             Dagger v6.0 X     Michael Constant     164      24
 7  41/ 17/ 42                   BigImps        James Layland     164      44
 8  49/ 39/ 12               Sunburst 33              Jay Han     159      14
 9  44/ 31/ 25                   CG-X IV     Brant D. Thomsen     157      35
10  49/ 42/ 10                        BS            J.Layland     156      43
11  41/ 34/ 25                 Iron Gate       Wayne Sheppard     148      40
12  35/ 26/ 39                    FatImp              Jay Han     144       1
13  40/ 50/ 10                   Silly 2         James Ojaste     130       7
14  41/ 54/  5                     Silly         James Ojaste     129       9
15  33/ 46/ 21           testing testing     Fredrik Ohrstrom     121      31
16  32/ 46/ 22                     Crimp              Jay Han     118       2
17  34/ 53/ 13                    VJX-2a         James Ojaste     115      28
18  28/ 42/ 31                     Bloom              Jay Han     114      12
19  30/ 50/ 20                Surprise7b         James Ojaste     109      10
20  32/ 59/  8                     VJX-2         James Ojaste     105      29

WOW!  Due largely to the efforts of Jay Han and James Ojaste, the '94
experimental hill has really changed over the last couple of weeks.  So far,
it looks like imp-spiral/stone combinations and scanners are dominating
the hill.  (Has anyone out there tried a paper or vampiric program?  I'd
be curious to know how it does.)
______________________________________________________________________________

HINTS and HELPS:

One of the most irritating things in corewars is handling those programs
that refuse to die.  You know what I mean:  your scanner/bomber/vampire
has stunned the opponent; and then, suddenly, the enemy comes to life in
the middle of your core-clear and finishes you off.

The '88 solution to this problem has been the two-pass core clear.  (I have
no idea who was the first person to use this technique, but it is now quite
common.)  During the first pass of the core-clearing loop, the code fills
the core with "SPL 0" statements; during the second pass, the code overwrites
the core with "DAT" statements.  The "SPL 0" instructions greatly increase
the odds that the program is no longer a threat, and the "DAT" insructions
are to kill your opponent off altogether.  This method is very efficient,
but it has some disadvantages as well:  multiple-pass core-clears can be
hard to set up, and they are often disabled by fast bombers.

A similar method that can be used with the '94 standard is to use your
core-clearing routine to "confuse" the core instead.  Take a look at the
following code:

	clear	spl.B	#0, <-20	; Equivalent to: SPL.B 0, <-20
		mov.I	2, <-11		; Overwrite the core
	confuse	djn.F	-1, >1		; Confuse the core
		dat.F	<-21, #10	; Give a pointer to work with

The first two lines are the '94 equivalent of a standard core-clear.
The "SPL 0" line generates processes, which the "MOV" uses to fill the
core with "DAT" instructions.

The last two lines are used to "confuse" the core.  The "DJN" instruction
will decrement both the A and B-field values of the instructions as it
proceeds forward through the core.  This decrementing is usually enough to
keep any program it meets from working correctly, so the 
standard part of the core-clear (which is working its way backwards
through the core) will have no problem completely killing the opponent when
it gets to it.  Since the "MOV" instruction in the core-clear gets the
processes created by the "SPL 0" before the "DJN" instruction does, it will
always complete first -- so the confusion will never reach the core-clear
itself.

This technique has several advantages over a two-pass core-clear.
In addition to being at least twice as fast, it is also easy to implement
and fairly rugged.  In fact, the "confuse" line can be bombed by a "DAT"
statement and the core-clear will still work.

There are several attributes of using this core-clearing method that cause
it to work well against imp-spirals as well.  The multiple processes
running during the clear will give your program a tie if the core-clear
is over-run before it has completed, and the imp-gate at the end will
(usually) stop imp-spirals if any remain when the core-clear is completed.

An important thing to notice is that the location pointed to by the
"confuse" line has a positive value.  This is because the "confusion" will
not work correctly if this value is zero.  (The decrementing and incrementing
cancel each other out.)

As a final test to see how well this idea works, I added a "confusion"
core-clear to the program "Rave 3" (from the last issue) and submitted it
to the hill to see how it does.  It is under the name "Testing an Idea".
It looks as if there are currently so many scanners on the hill that the
adding of the two extra lines turned into a disadvantage.  (Perhaps I should
have saved this hint for a later issue instead! :-)
______________________________________________________________________________

Looking to the Future:

The lastest draft of the standard has been on soda.berkeley.edu for over
a month now (as /pub/corewar/documents/icws94.0202.Z).  Take a look at it
and let the newsgroup know what you think.  There are some interesting 
additions to the former '94 draft standard, so it's worth your effort
to get a copy and study it.

Also, please submit your programs to the '94 hills.  We'd love to have your
best KOTH warrior on the standard '94 hill, even if it is still '88 
compliant.

If you have any comments or questions about the '94 hills or the '94
standard that you think might be of general interest, please let me know.

Good luck, and happy computing!
______________________________________________________________________________

Brant D. Thomsen, Editor	   Snail mail:	1197 East 6290 South
(bdthomse@peruvian.cs.utah.edu)			Salt Lake City, UT  84121
University of Utah				U.S.A.
-- 
Brant D. Thomsen                        The teaching of BASIC in schools
(bdthomse@peruvian.cs.utah.edu)         should be considered a criminal act.
University of Utah                                              - Dijkstra
2002-2005 corewar.info. Logo C. Schmidt