AT91_TWI_IMR
dev->imr = at91_twi_read(dev, AT91_TWI_IMR) & AT91_TWI_INT_MASK;
const unsigned irqstatus = status & at91_twi_read(dev, AT91_TWI_IMR);
const unsigned irqstatus = status & at91_twi_read(dev, AT91_TWI_IMR);