1. A method to automatically determine an optimal number format representation for a model or code to be implemented in a custom integrated circuit (IC), comprising: a. determining a ratio of dynamic range to static range in the model or code, and selecting a floating point or a fixed point number representation based on the ratio; b. determining an optimal number representation format based on a cost function that includes hardware area cost and power cost associated with a predetermined bit precision arithmetic; c. automatically generating a processor architecture customized to the optimal number representation format; and d. synthesizing the generated processor architecture into a computer readable description of the custom integrated circuit for semiconductor fabrication.