Here’s an app note from Xilinx on calculating power consumption for a CPLD.
The goal of this application note is to discuss XC9500XL CPLD power estimation and optimization and provide the reader with an understanding of sense-amplifier based CPLD power dissipation. A brief discussion of the process for estimation is given. With this information, you can accurately assess the power dissipation for a design. You will also be given guidelines permitting you to make key choi ces to manage the power dissipation of your design and understand the package thermal limits.