Thesis (M.Sc.)--Chulalongkorn University, 2013

Energy consumption around the world increases exponentially. One of the causes to blame is electronic devices such as personal computers, embedded devices, and smartphones. To reckon with reducing energy consumption involves efficient hardware and software. This research focuses on the software part, in particular, how to write a program that is energy efficient. The proposed technique is based primarily on local variable reallocation in C programs to exploit the advantages of global variables and register variables. The experiment was conducted on 24 test programs by comparing between local variables and modified program using global variables and register variables. Analysing the amount of energy consumed is performed at the instruction level. It was found that global variables were the best choice. The benefits are fewer redundant allocations and memory accesses, thereby less energy will be consumed and will help the program execute faster.