Expand

The expand operation (or qpl_operation.qpl_op_expand) is in some sense the inverse of the qpl_operation.qpl_op_select operation (see Select for more information). This also reads a bit vector from source-2. If you take the output of expand and perform a select operation on it (with the same bit vector as source-2), then you get back the same data as the original source-1.

Note

The output of expand may not be in a format readable by the select operation (for example, in the case mentioned in Output Modification for Nominal Bit Vector Output)

In this operation, the bit-width of the output is the same as the bit width of source-1 (unless explicitly changed by qpl_job.out_bit_width) but the number of output elements is equal to the number of input elements on source-2. So for this operation, the job field qpl_job.num_input_elements actually contains the number of elements in source-2 rather than source-1.

Each 0-bit from source-2 writes a zero to the output. Each 1-bit writes the next entry from source-1.