What happens with a repeated string (prefixes REP, REPZ and REPNZ) when the resume flag is set? Is it cleared after a single repeat, or after all repeats execute?

Logically each repeat is one instruction(without fetching), so after the first repeat it will trap (again), but for speed purposes it might actually be after all repeats are done?

What happens in such a case? Currently UniPCemu clears the flag after the first I/O step(so (E)CX will have decremented once before faulting into the debugger on the next repeat or instruction after the string instruction), but perhaps that isn't the case?