Methods and apparatus are disclosed using an index array and finite state machine for scatter/gather operations. Embodiment of apparatus may comprise: decode logic to decode scatter/gather instructions and generate micro-operations. An index array holds a set of indices and a corresponding set of mask elements. A finite state machine facilitates the scatter operation. Address generation logic generates an address from an index of the set of indices for at least each of the corresponding mask elements having a first value. Storage is allocated in a buffer for each of the set of addresses being generated. Data elements corresponding to the set of addresses being generated are copied to the buffer. Addresses from the set are accessed to store data elements if a corresponding mask element has said first value and the mask element is changed to a second value responsive to completion of their respective stores.