A novel architecture based on mixed mode BIST for sharing among multiple logic cores on an system-on-a-chip is presented. In the architecture a single-polynomial LFSR with maximum degree in the multiple cores can be selected to generate pseudo-random patterns to cover the easy to detect faults for the all cores. For the remaining faults of the each core deterministic test patterns can be compressed by a two-dimensional compression scheme, where the LFSR encodes the seeds of a folding counter as the seeds of the LFSR so as to reduce amount of test data storage, and all of the cores under test can use the unique LFSR to decompress the encoded seeds. Experimental results indicate that the proposed scheme can achieve a significant amount of compression for test data storage, and the simple and flexible architecture can be directly embedded on chip for systems-on-a-chip test.