A midweek review of Corewar
                            September 15, 1993
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  I.  The Standings:

 #  %W/ %L/ %T                      Name               Author   Score     Age
 1  45/ 42/ 12            Iron Gate 1.01       Wayne Sheppard     148     225
 2  45/ 47/  8                 Agony 6.0        Stefan Strack     142      34
 3  41/ 39/ 20         Beholder's Eye v2         W. Mintardjo     142       2
 4  32/ 23/ 45             Night Crawler       Wayne Sheppard     142    1082
 5  32/ 25/ 43                       ttt        nandor sieben     140     306
 6  37/ 35/ 28           QuickFreeze t24              P.Kline     139       4
 7  42/ 46/ 12              Dragon Spear             c w blue     139    1184
 8  29/ 20/ 51                     pMARS        pMARS project     139     131
 9  30/ 24/ 46               Impact v1.0         Anders Ivner     137     219
10  30/ 25/ 45                Imprimis 7              P.Kline     135     322
11  36/ 37/ 27              Keystone t13              P.Kline     135      40
12  32/ 29/ 39              FlyPaper 3.0            J.Layland     135     506
13  36/ 37/ 26         Winter Werewolf 3         W. Mintardjo     135     400
14  40/ 47/ 13                   Impurge     Fredrik Ohrstrom     134     406
15  36/ 40/ 24             Leprechaun 1b         Anders Ivner     133     150
16  38/ 43/ 20           Grimm's Vampyre             c w blue     132     265
17  29/ 26/ 45               Sphinx v2.8         W. Mintardjo     131    2080
18  38/ 45/ 17                Eclipse II              P.Kline     131       1
19  28/ 27/ 46                     Hydra      Stephen Linhart     129     151
20  34/ 39/ 27                  Herem VI         Anders Ivner     129     254

21  26/ 42/ 32            Disruptor v2.7     Fumitaka Hayashi     110      11

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 II.  The Basics:

       -Core War Archives are available via anonymous FTP at 
        soda.berkeley.edu in pub/corewar...

       -FAQ for this newsgroup is available via anonymous FTP at
        rtfm.mit.edu as pub/usenet/news.answers/games/corewar-faq.z

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III.  The Scoop:

Man, things have been tight on the Hill.  Several days only 15 points
separated the top from the bottom.  When scores are that close, every
challenge mixes up the rankings making it hard to tell what is holding
the top spot.  In part this is due to my own Keystone, which brought
down the scores of those high-flying scanners and also the score of 
Fly Paper.  Keystone looks exactly like Emerald 4 (except for constants),
unless it thinks the opponent is paper, then it goes for the tie.  Any
guesses as to how a stone detects paper?

Last week I suggested that imp-vampire combos like Snake and Incrimination
might have been made obsolete by anti-vamp programs.  For those of you
not getting reports from KotH (you have to have a fighter on KotH),
W. Shepard put up Snake just to see.  It placed 11th. But he knocked it
off because "it takes too many points away from Night Crawler".
Now, I thought we were trying to knock OFF the imps :-)

W. Mintardjo has been recycling some of his old favorites, Medusa and
Beholder's Eye.  They are still tough.  Working on some improvements
or just more constant tweaking?  And what happened to Deck of Many Things
by C. Blue?  Looked very good but he knocked it off.  Seems like there
are a lot of tough programs out there.  Maybe KotH is too small.
Or maybe people are exercising their warriors in preparation for the 
upcoming tournament.

Can anybody give us a report on KotH at Stormking?

Welcome back! to Mark Durham, who is reconnected now, through Delphi.

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 IV.  The Outlook:

 3  30/ 24/ 46       Deck of Many Things             c w blue     137       1
 5  39/ 39/ 23              sub-type-cmp             c w blue     139       1
 5  39/ 40/ 20         Beholder's Eye v2         W. Mintardjo     138       1
 8  36/ 34/ 30           QuickFreeze t24              P.Kline     137       1

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  V.  The Quick Look:

18  38/ 45/ 17                Eclipse II              P.Kline     131       1
19  25/ 39/ 36            Disruptor v2.7     Fumitaka Hayashi     112       1
19  39/ 51/ 10                 Agony 7.0        Stefan Strack     128       1
20   3/ 69/ 28             sub-type-impx             c w blue      37       1
20  11/ 31/ 58                bangle 4.1        Steve Gunnell      90       1
20  16/ 63/ 21            Smart Bomb 2.0     Devin Kilminster      68       1
20  24/ 58/ 18                    ScanR2        Jonathan Wolf      91       1
20  25/ 62/ 13                    Spiral      Stephen Linhart      87       1
20  35/ 44/ 21             Distance v6.5     Brant D. Thomsen     127       1
21   1/ 37/ 62          Clinched Fist v1         Mitch Burton      66       0
21   2/ 50/ 47                     sweep     Fumitaka Hayashi      55       0
21   2/ 78/ 21            Jump! Jump! v1         Mitch Burton      25       0
21   4/ 39/ 56                   impi II                Geoff      69       0
21   4/ 65/ 30                Thief v1.3         Mitch Burton      44       0
21   5/ 88/  7                   Jester3     Fumitaka Hayashi      23       0
21   8/ 56/ 36                    JuMPer         Mitch Burton      61       0
21  11/ 44/ 45              Shwing! v2.1         T. H. Davies      78       0
21  13/ 45/ 42  <oh no not another> test      Campbell Fraser      81       0
21  16/ 62/ 22                    Invest      Andre van Dalen      70       0
21  18/ 75/  7         Daemon's BANE ]I[                Bryan      62       0
21  19/ 78/  3                   Inswarm      Andre van Dalen      60       0
21  20/ 71/  9                     Dwarf           AK Dewdney      69       0
21  24/ 24/ 52        Incrimination v2.0     Brant D. Thomsen     123       0
21  25/ 49/ 26                     BombR        Jonathan Wolf     101       0
21  26/ 56/ 18                       BS1            J.Layland      97       0
21  29/ 60/ 11                     ScanR        Jonathan Wolf      97       0

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 VI.  The Hint:

Let's talk about a little-used bombing technique that I picked up from
'B-scanners-live-in-vain' by Matt Hastings, master of tiny programs.

;redcode quiet
;name B-scanners live in vain
;author Matt Hastings
        add #1226,3
start   jmz -1,@2
b1      mov grave,@1
b2      mov prog,<-2+1226
        jmn -4,-4
prog    spl 0,0
        mov @10,<-1
grave   jmp -1,0

(The labels 'b1' and 'b2' were added for this discussion.)

Notice how b1 moves 'grave' to where b2 is pointing, then b2 moves
'prog' to one position above that by using the 'grave' b1 dropped
as a pointer.  This was Matt's solution to the problem of dropping
a second bomb (prog) without decrementing his bscan pointer, which
would have altered his scan sequence unpredictably.  Also, notice
that prog and grave have zero b-operands, making them invisible
to his own scanning and to other b-scanners.  Today there
are few successful b-scanners so most of us don't bother about zero
b-operands.  And of course, under the '94 standard, you could scan
for a-operands.

Anyway I want to focus on the use of a first bomb as a pointer
for a second.  The pointer can be anywhere.  For example, a dumb
spl-jmp type bomber could be written like this:

step      equ 2936      ; mod-8 step
next      add #step,b2
b1        mov bjmp,@b2
b2        mov bspl,@bspl
b3        jmp next
bspl      spl 0
bclr      mov 10,<-10
bjmp      jmp -1,step-1

In this version, the bjmp's are dropped and used as pointers so the
bspl's are dropped step-minus-1 locations away.  The final bspl is dropped
on b3 to start the core-clear.

Next, look at this dat-bomber which bombs N and N+DIST which is what
QuickFreeze does. (W. Mintardjo and A. Ivner take note :-)

DIST    equ 1000
b1      mov bbmb,@b2
b2      mov bbmb,@-100
        sub #4,b2
        jmp b1
bbmb    dat #DIST

With a little work this could be turned into a bombing loop that would
bomb two and decrement two locations for every four instructions.

Of course any constant could be used, 4000 for instance.

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VII.  The End:

Paul Kline
pk6811s@acad.drake.edu