Automatic floating to fixed point translation and its application to post-rendering 3D warping

The automatic conversion of floating point software implementations of algorithms to a equivalent fixed point implementation which can be efficiently implemented in an FCCM remains an obstacle in the rapid systems prototyping design flow. Floating point to fixed point conversion is tedious, error prone and requires a good knowledge of fixed point computer arithmetic. This paper describes a software system called fp designed to automate the process. It consists of a fixed point C++ class; a profiler which is used to determine the number of bits of precision required for each signal in the hardware implementation; an optimiser which finds the minimal number of bits required for a specified degree of accuracy in the implementation and finally and a compiler which takes the information collected by the system and outputs synthesisable VHDL code. A post-rendering 3D image warping application designed using this system is used as an example.