Imps are a special sub-type of paper warriors. They replicate by moving all the main body instructions somewhere else, using the mov command.

Besides the normal imp, there are imp-worms, imp-guns, imp-rings, imp-spirals, and gate-crashing imp-spirals.

The basic imp consists of one statement, mov 0,1 .
What this does is move the current instruction to the next instruction (mov 0,1 means "move instruction at relative position 0 to relative position 1". The core will then execute the next instruction, repeating the process.

Note that due to this, normal imps cannot ever win (unless the enemy commits suicide). If an enemy warrior is overwritten with mov 0,1 , it'll just start executing that command as well, creating a tie.

An normal imp is next to useless, since one hit will kill it (a DAT at relative position 1 after mov 0,1 has been executed).

An imp gun continually creates new imps. Its code is as follows:

gun mov imp, 1337 ; move instruction at imp to relative pos 1337
spl @gun          ; start a new process at position 1337
add #1337, gun    ; add 1337 to the b-field of gun
jmp gun           ; and reload
imp mov 0,1       ; the imp
What happens is that it first places a mov 0,1 instruction at 1337. Then it splits to a new process at that location, starting the imp, jumps back to the label "gun", and repeats. This warrior can never win, and is very slow (due to the immense number of processes generated). It is very hard to destroy, but scissors can do it, by subverting one of the processes.

The best passive defense against an imp is known as an imp-gate. The imp-gate is an instruction that decrements some static location prior to the first code instruction of the warrior. E.g:

warrior          ; some attack code here
jmp warrior,<-10 ; decrement relative position -10
If an imp instruction has just been copied to position -10 when the jmp instruction is executed, it will be decremented, meaning that the next instruction the imp executes is not mov 0,1, but mov 0,0, which does absolutely nothing, and the imp dies on the next cycle (the core executes the next command, which is a DAT 0,0 (core is initialized to dat 0,0), which kills it).

An imp-ring is composed of multiple imps that copy each others' instructions, by using multiple processes. This way, if an enemy is overrun by one of the imps, it dies, since it cannot execute the imp instruction and survive without the help of the other imps in the ring. E.g:

one    JMP imp-2666 ; jump to future imp location 1 (+1)
start  SPL c        ; split to the next instruction
       SPL imp+2667 ; split to future imp location 2
imp    MOV 0,2667   ; copy to future imp location 2
end start
The first process will (after the "launch" (the term for using SPLs to initialize the ring)) execute mov 0,2667. This moves the mov instruction to another future imp location plus one, so that the next process can execute it. When the next process executes it, the MOV is copied so that the third process won't die. If the size of core is 8000, then the third process will keep the first one alive, causing the ring to crawl onwards. If an enemy warrior is hit with a mov 0,2667, it'll execute it and die, since there is no process to back it up.

A spiral is a more durable type of ring. A gate-crashing spiral is invulnerable to ordinary imp-gates.

Imps are often combined with a bomber, because imp as a paper beats stones, and the bomber as a stone beats scissors.

Log in or register to write something here or to contact authors.