How do I implement the input shift register feature for the multiply-only mode in the Stratix™ device digital signal processing (DSP) block?

Description

When implementing the input shift register feature in the multiply-only mode, you can use the LPM_MULT MegaWizard^® Plug-In. However, if you want to use other features, (for example the input shift register or the dynamic sign control feature of the DSP block,) you will need to use the ALTMULT_ADD megafunction, and specify the number of multipliers to be "1" in order to bypass the adder stage.