Compare in forth

Compare is a string comparison word in Forth
compare (c-addr-1 len1 c-addr-2 len2 -- n )

This takes two strings and leaves a flag. (0 for a match. -1 less than. +1 greater than.)
Typically this is written in either C or Assembler and documented in some kind of psuedo-pascal such as source-index := source-index + 1;