25 - Fixed Point Arithmetic in VHDL

Abstract

This chapter introduces the concept of fixed point arithmetic in VHSIC hardware description language (VHDL), where VHSIC stands for very high speed integrated circuit. It also provides a package of functions and types to get started using VHDL. It describes the basic idea about what fixed point arithmetic is and how it can be used in field programmable gate arrays (FPGAs) design. A simple approach is used in this chapter that illustrates how the basic functions operate. The chapter begins with an introduction to fixed point functions. Further, it also provides description of testing the fixed point function. However, it is stressed that this package of functions and types to get started using VHDL is purely for exemplar designs. One can use this package in a VHDL model by compiling the package into the current work library. This provides access to all the fixed point functions and types required. Thus, the chapter encourages the reader to either use commercially available libraries for optimum performance or to develop their own libraries.