Article 715 of rec.games.corewar: From: ajpierce@med.unc.edu (Andrew Pierce) Newsgroups: rec.games.corewar Subject: Synch 4 Message-ID: <1992Apr8.133256.7898@samba.oit.unc.edu> Date: 8 Apr 92 13:32:56 GMT References: <1992Apr8.131527.7093@samba.oit.unc.edu> Sender: usenet@samba.oit.unc.edu Organization: UNC-CH School of Medicine Lines: 63 Nntp-Posting-Host: salvo.med.unc.edu Synch 4 has survived more than 10 successful challenges on KotH. Here is the code. I really like this one. When it first appeared on KotH, the Synch series went immediately to #1 and stayed there for about a week. The highest score I saw reported was 978 or so, by Synch 3. Synch 4 is strategically almost identical to Synch 3, yet scored lower -- I take this to be due to random statistical influences on battles on the hill. Synch 4 is an off-axis cmp scanner -- it compares locations to see if they have been changed, but these locations are not coresize/2 apart so that programs cannot use the "mirror defence" of having two identical copies coresize/2 away from each other. Once an altered location has been found, Synch makes a decision: Case 1: the preceding instruction to the altered one has also been altered: In this case Synch 4 assumes it has found executing code and bombs with spl 0, following with a clear routine. Case 2: the preceding instruction to the altered one has not been altered: In this case Synch 4 uses the same strategy which my program "Stoopify" used and which I have learned the program "Hideout" also uses. This is based on the idea that "lightning never strikes twice in the same place". When building a pattern bomber, it is not very efficient to rebomb a location you have already hit (assuming non-motile programs) so Synch 4 transfers a small bombing routine on top of one of the bombs it has found. In some ways then, Synch 4 is somewhat parasitic: it beats the efficient pattern bombers but loses to "poorly designed" pattern bombers. The hill though has lots of efficient bombers on it, such as Small 4, which keep the programs that Synch 4 tends to lose to off the hill. -Andy ajpierce@med.unc.edu ;redcode verbose ;name Synch 4 ;author Andy Pierce (ajpierce@med.unc.edu) ;strategy cmp scan, spl bomb, clear core ;strategy v2: reduce footprint, convert losses to ties, better tactics ;strategy v2a: convert ties to wins, marginally better strategy ;strategy v3: reduce footprint again, more extensive smear routine ;strategy v4: move scan off axis, minor tactics fix start cmp 2939,6988 jmp hit,0 back sub offset,start jmp start,0 hit cmp @start,start-1 jmp 2,0 add flip,start slt #30,start jmp back,0 mov bomb,@start cmp