A method and apparatus are described for using a previous column pointer to read a subset of entries of an array in a processor. The array may have a plurality of rows and columns of entries, and each entry in the subset may reside on a different row of the array. A previous column pointer may be generated for each of the rows of the array based on a plurality of bits indicating the number of valid entries in the subset to be read, the previous column pointer indicating whether each entry is in a current column or a previous column. The entries in the subset may be read and re-ordered, and invalid entries in the subset may be replaced with nulls. The valid entries and nulls may then be outputted.