According to the Catholic Church, is the priest in persona Christi during the mass?

I know that the Catholic Church teaches during confession the priest acts "in persona Christi" (in the person of Christ). Since the mass is meant to be a re-presentation of Christ's sacrifice on the cross, and this occurs in the re-enactment of the Last Supper, does the priest act in persona Christi? Are there only certain points when this is the case (for instance is he not during the Homily)?