Translation of "if one is decoding" into Cornish

The impersonal form in Cornish is a specialised verb form that does not specify a subject (no ‘I’, ‘you’, ‘he/she’ or ‘one’ is mentioned), acting similarly to the English ‘one’ (as in ‘one does’) or ‘they’ (as in ‘they do’) or ‘you’ (as in ‘you do’) or the passive voice (‘it is done’ / ‘it is seen’). It is often used to express general, habitual, or indefinite actions. It can be used as an independent verb or with an auxiliary verb like GUL (‘do’) or BOS (‘be’). EDER is an impersonal indicative present form of BOS.