21. The search engine of claim 18 , wherein: a second of the commands comprises a count command embodying the specified range of instances; and a second of the co-processors is dedicated to execute the count command to generate a range signal indicating whether the number of input characters in the selected portion falls within the specified range of instances.
21. The search engine of claim 18 , wherein: a second of the commands comprises a count command embodying the specified range of instances; and a second of the co-processors is dedicated to execute the count command to generate a range signal indicating whether the number of input characters in the selected portion falls within the specified range of instances. 26. The search engine of claim 21 , wherein: the regular expression further includes an exact pattern; a third of the commands comprises a check string command embodying the exact pattern; and a third of the co-processors is dedicated to execute the check string command to determine whether the input string matches the exact pattern.