1. An integrated circuit comprising: processing logic operable to execute a program; watchpoint monitoring logic operable to review values of one or more signals occurring within the integrated circuit as a result of execution of said program, the watchpoint monitoring logic comprising: a storage element for storing configuration data; an interface via which the configuration data is software programmable having regard to a set of watchpoint values of said one or more signals to be monitored; and hash logic operable for a value to be reviewed to perform a hash operation on that value in order to reference the configuration data to determine whether that value is either definitely not a value within said set of watchpoint values or is potentially a value within said set of watchpoint values; the watchpoint monitoring logic being operable to generate a trigger signal if it is determined that that value is potentially a value within said set of watchpoint values, the trigger signal being used to trigger a further monitoring process, wherein the trigger signal is used to trigger as at least part of said further monitoring process a checking operation to determine whether the value causing the trigger signal to be generated is a value within said set of watchpoint values; and if the number of watchpoint values in said set of watchpoint values is increased, the configuration data being reprogrammed via the interface without increasing the size of the storage element.