In case of nomenclature of unsaturated diastereomeric compounds which are geometric isomers, a different nomenclature is allowed. However, the CIP rules for determining priority are still used. Then the groups on each carbon of the double bond are marked according to priority. Now if the groups having higher priority are on the same side, then the group is labelled Z while if the groups of higher priority are not on the same side of the double bond then the compound is labelled as E. This system may be understood from the examples below.

For the chiral centre, 
Following rule 1, bromo group gets first priority

Following rule 3, group gets second priority.

Following rule 2, methyl group gets third priority.