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Operation Reduction for Low Power is a ASIC Program transformation technique used to reduce the power consumed by a specific application. A program transformation is any operation that changes the computational structure such as nature and type of computational models, their interconnections, sequencing of operations keeping the input output behavior intact. We basically use Operation reduction to reduce the number of operations to be done to perform a task which reduces the hardware required and in turn power consumption. For example in a given Application specific IC reducing the number of independent additions required automatically reduces the adders required and also the power consumed. == Operation Substitution == Operation Substitution is one of the operation reduction techniques where certain costly operations are substituted by relatively cheaper operations which reduce power consumption. Some typical examples of operation substitution techniques are given as follows: #Multiplication by Adds/Subtracts: The multiplication of two numbers if costly compared to addition of two numbers therefore substituting it with addition is profitable. For example to calculate y = x2 + Ax + B we can calculate x2, Ax, and add both of them to B which has 2 multiplications, 3 additions or we can convert it into y = x(x+A) + B where we can calculate x+A multiply it with x and add B where we have 1 multiplication and 2 additions, both approaches have same critical path length but 2nd one has lesser multiplications which saves power. #Computation of Sine/cosine/tan: Computing trigonometric functions might also turn out to be quite costly where as substituting them with lesser order Taylor expansion makes them less power consuming but we may lose on approximation grounds which is a trade-off one should keep in mind. #Multiply-add by MAC: Multiply–accumulate operation is a common step that computes the product of two numbers and adds that product to an accumulator. The hardware used for this purpose is called multiplier–accumulator (MAC). Using MAC's also decrease the power consumed. Basically a MAC does multiplication and addition in one unit. #Reducing Memory Access: Changing the structure of the program by replacing the operations which require frequent memory access with those need less memory access is also profitable as memory access is a costly operation. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Operation Reduction for Low Power」の詳細全文を読む スポンサード リンク
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