There are 128 bits stored in the Pre Fetch Buffer, and instructions are supplied from the buffer. As soon as you transfer data into the Pre Fetch Buffer, another speculative fetch is done by fetching another 128-bit-wide memory chunk from the Flash memory, bringing it into the data latch. Then, once the last instruction in the Pre Fetch Buffer is reached, the data latch contents are then transferred to the Pre Fetch Buffer and another fetch sequence starts.