The two best papers describing some of the SPADE features are:

• “Automatic Generation of Systolic Array Designs For Reconfigurable Computing”, Proc. Int. Conf. Engineering of Reconfigurable Systems and Algorithms (ERSA 2002), Las Vegas, Nevada, June 24–27, 2002, pages 176–182. CSREA Press, provides much more background on related tool work and plus additional mathematical details  (associated presentation).
• “Constraint Directed CAD Tool For Automatic Latency-Optimal Implementation of 1-D and 2-D Fourier Transforms” deals primarily with issues related to use of a CAD tool to automatically derive the base-4 systolic architecture (associated presentation).