This paper proposes a low-power ASIP generation method by automatically extracting minimum execution conditions of pipeline registers for clock gating. For highly effective power reduction by clock gating, it is important to create minimum execution conditions, which can shut off redundant clock supplies for registers. To automatically extract the conditions, our proposed method employs micro-operation descriptions (MODs) that specify ASIP architecture. Utilizing MODs through the ASIP generation processes, our proposed method automatically extracts the minimum execution conditions. Experimental results show that the power consumption of the pipeline registers in ASIPs generated with the proposed method is reduced about 80% compared to ASIPs that are not clock gated, and about 60% compared to ASIPs that are clock gated by Power Compiler with negligible delay and area overhead.