30In this particular example, the mask value is FFFF hexadecimal, which means all 1’s in a 16-bit field. This mask value tells the sequencer instruction to regard all bits of each B3 word that is read. To contrast, if the mask were set to a value of 000F hexadecimal instead, the sequencer would only pay attention to the four least-significant bits of each B3 word that is read, while ignoring the 12 more-significant bits of each 16-bit word. The mask allows the SQO instruction to only write to selected bits of the destination word, rather than always writing all 16 bits of the indexed word to the destination word.