: In this research, a fixed-point multimedia co-processor is designed and tested into an ARM-10 based mobile graphics processor for portable 2-D and 3-D multimedia applications. The fixed-point co-processor architecture with dual operations realizes advanced 3-D graphics algorithms and various streaming multimedia functions in a single hardware while consuming low power. The instruction-wise clock gating on fixed-point SIMD datapath allows fine-grained power control in application-specific manner. The co-processor takes 10.2mm2 in 0.18µm 6-metal standard CMOS logic process and achieves 50Mvertices/s graphics performance with 75.4mW power consumption. The implemented chip is successfully demonstrated on the development board equipped with software graphics library and evaluation environment.