Energy-efficient and low-power designs issues are becoming more important in modern processors. In this paper we propose an energy-efficient adaptive multiple-issue architecture for portable systems. The architecture utilizes a hardware-software cooperation approach to minimize hardware overhead while providing control flexibilities to programs and operating systems. Optimizations are made based on the program execution profile. Simulation results show that the adaptive architecture improves the performance by an average 20% with a maximum 8% reduction in energy consumption compared with the baseline model. The increase in power dissipation is restricted to less than 6%.