Indian citizen. I have been granted 6 month multientry Schengen visa from Spanish embassy in Dublin. However duration of stay is mentioned as 40. I don't know what that means. I thought we are allowed to stay 90 days in 180 day period. Does duration here refer to continuous stay, meaning I cannot stay in Schengen continuously for more than 40 days. Before it exceeds 40, I should exit and re-enter again. Please advise.

Indian citizen. I have been granted a 6-month multi-entry Schengen visa by the Spanish embassy in Dublin. However, the duration of stay is mentioned as 40. I don't know what that means. I thought we are allowed to stay 90 days in a 180-day period. Does duration here refer to continuous stay, meaning I cannot stay in Schengen continuously for more than 40 days, and before it exceeds 40, I should exit and re-enter again? Please advise.