A built-in self-test (BIST) based on a signature-analysis (one of the data compression techniques) has been implemented in a 24 bit floating point digital signal processor (DSP). By using only a single pair of linear feedback shift registers (LFSR's) and 253 words of instruction of the DSP, 95% of the functional blocks are self-tested. The number of test patterns is 35 million. It takes only 2.6 seconds for the test at fc26.7 MHz. The overhead of the BIST hardware is about 2.0% of the die size. By comparing the pass rate in a conventional function test to the BIST, nearly the same fault coverage is obtained. This result shows that the BIST is effective for VLSI processors, such as DSPs. By improving this method, manufacturing go/no-go tests without expensive test equipment will be possible.