1. A method of using a previous column pointer to read a subset of entries of an array in a processor, the array having a plurality of rows and columns of entries, each entry in the subset residing on a different row of the array, the method comprising: generating a previous column pointer 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.