x86 Asm of a very different syntax (neither Intel nor AT&T), to be fair. For a second, I thought it was ARM. Then I started to parse some of the syntax and realised it could be made even more minimal, e.g. this function

    ;; in_set function 
    ;; Receives a Char in R0, char* in R1 
    ;; Return result in R0 

based on what it seems to do, can almost certainly be replaced with a simple repnz scasb.