I think I forgot the reason for this SFR manipulation in microcontrollers; like, checking the TWSR in twi.
The technique for checking the values of the TWSR is by masking it with another variable or a value.
So, why not checking the TWSR directly in; for example, switch function for checking the values of TWSR?
Status = TWSR & 0xF8;
Or, substitute it in any function; like,
digitalRead(TWSR);. DO I have to mask it? If so then why?