Author Topic: Core War (or Core Wars) is a programming game of battling programs  (Read 2150 times)

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Core War (or Core Wars) is a programming game of battling programs for Windows

Corewar - An Introduction to Hostile Programming

Corewar is a game from the 1980's, played between computer programs written in Redcode, a language similar to assembly. The programmers design their battle programs to remove opponents from the memory of the MARS virtual computer by any means possible.

Some of the simpler techniques include blindly overwriting memory, searching for the opponent or spawning off new processes. These are commonly known as stone, scissors, paper after the popular playground game. Stone usually wins against scissors, scissors normally defeat paper, and paper mostly beats stone.

Corewar is a game played between two or more computer programs on behalf of the players who create them. Known as warriors, these programs are written in Redcode, a low-level language similar to assembly. Warriors battle to eliminate all opponents in the core memory of the MARS virtual computer.

The hills provide the typical battleground for Redcode programs. When a warrior is submitted to a hill, it fights against warriors currently on the hill. It scores according to the number of wins, ties and losses. The challenger will enter the hill if its score is higher than the lowest achieved by a current hill warrior. The lowest scoring warrior will then be pushed off.

A variety of different hills adds to the diversity of gameplay. Some are round robin, where each warrior fights every other in a one-on-one battle. Others are mêlée (multi-warrior) where all warriors battle simultaneously in core. To this is added a selection of core sizes, number of processes available, etc.

The highest scoring warrior on the hill claims the title King of the Hill. A warrior's age is measured by the number of successful challenges it survives. Interestingly, quite a few of the longest surviving warriors were never KotH.

Core War
From Wikipedia, the free encyclopedia

Core War

Core War (or Core Wars) is a programming game in which two or more battle programs (called "warriors") compete for the control of the "Memory Array Redcode Simulator" virtual computer ("MARS"). These battle programs are written in an abstract assembly language called Redcode. At the start each battle program is put into the memory array at a random location, after which each battle program can execute one instruction in turn. The object of the game is to cause all processes of the opposing program(s) to terminate (which happens if it executes a special instruction), leaving the victorious program in sole possession of the machine.


Warriors are commonly divided into a number of broad categories, although actual warriors may often combine the behavior of two or more of these. Three of the common strategies (replicator, scanner and bomber) are also known as paper, scissors and stone, since their performance against each other approximates that of their namesakes in the well known playground game.

A bomber (or rock) blindly copies a "bomb" at regular intervals in the core, hoping to hit the enemy. The bomb is often a DAT instruction, although other instructions, or even multi-instruction bombs, may be used. A bomber can be small and fast, and they gain an extra edge over scanning opponents since the bombs also serve as convenient distractions. Bombers are often combined with imp spirals (see below) to gain extra resiliency against replicators. The second published warrior in Core War history, Dwarf by A. K. Dewdney, was a bomber.

A replicator (or paper) makes repeated copies of itself and executes them in parallel, eventually filling the entire core with copies of its code. Replicators are hard to kill, but often have difficulty killing their opponents. Replicators therefore tend to score a lot of ties, particularly against other replicators. The earliest example of a replicator is Mice by Chip Wendell.
A silk is a special type of very rapid replicator, named after Silk Warrior by Juha Pohjalainen. Most modern replicators are of this type. Silk replicators use parallel execution to copy their entire code with one instruction, and begin execution of the copy before it is finished.

A scanner (or scissor) is designed to beat replicators, usually by bombing memory with SPL 0 instructions. This causes the enemy to create a huge number of processes which do nothing but create more processes. This slows down useful processes. When the enemy becomes so slow that it is unable to do anything useful, the memory is bombed with DAT instructions.
A scanner doesn't attack blindly, but tries to locate its enemy before launching a targeted attack. This makes it more effective against hard-to-kill opponents like replicators, but also leaves it vulnerable to decoys. Scanners are also generally more complex, and therefore larger and more fragile, than other types of warriors.

A vampire or pit-trapper tries to make its opponent's processes jump into a piece of its own code called a "pit". Vampires can be based on either bombers or scanners. A major weakness of vampires is that they can be easily attacked indirectly, since they must by necessity scatter pointers to their code all over the core. Their attacks are also slow, as it takes an extra round for the processes to reach the pit.

A one-shot is a very simple scanner that only scans the core until it finds the first target, and then permanently switches to an attack strategy, usually a core clear. Myrmidon by Roy van Rijn is a simple, yet effective oneshot.
« Last Edit: March 28, 2014, 12:41:27 PM by Software Santa »


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