1. Introduction

complexpack is a simple complex arithmetic package written in VHDL. It is based ona code example present in the RASSP series of VHDL lectures. Compared to the RASSP version, the following have beed added:

• conjugate function.

A complex number is defined by the pair (real-part, imaginary-part) where both items of the pair are numbers. A common algebraic representation for complex numbers is:

where:

• z is the resulting complex number
• a is the real part of the number also written as a = Re(z)
• b is the imaginary part of the number also written as b = Im(z)
• i is the imaginary unit and has the value of sqrt(-1).

Currently, the complexpack package implements the following:

• the constants re and im, which specify addresses for an array-based representation of a complex number
• type definition for a complex number
• interface and implementation for complex arithmetic functionality
  • to_complex (real, real): form a complex number
  • +: add two complex numbers
  • -: subtract one complex number from another
  • *: multiply two complex numbers
  • /: divide two complex numbers
  • conjugate(complex): return the conjugate of the given complex number

All of the above functions return an item of the complex data type.

complexpack is distributed along with a simple VHDL testbench exercising basic functionalities.

2. File listing

The complexpack distribution includes the following files:

/complexpack	Top-level directory
/bench/vhdl	Benchmarks VHDL directory
complexpack_tb.vhd	A simple testbench.
/doc	Documentation directory
AUTHORS	List of complexpack authors.
BUGS	Bug list.
ChangeLog	A log for code changes.
COPYING	The LGPL, version 3, governs complexpack.
README	This file.
README.html	HTML version of README.
README.pdf	PDF version of README.
rst2docs.sh	Bash script for generating the HTML and PDF versions.
THANKS	Acknowledgements.
TODO	A list of future enhancements.
VERSION	Current version of the project sources.
/rtl/vhdl	RTL source code directory for the package
complexpack.vhd	The complex arithmetic package.
/sim/rtl_sim	RTL simulation files directory
/sim/rtl_sim/out	RTL simulation output files directory
complexpack_results- .txt	Output generated by the complexpack_tb.vhd test.
/sim/rtl_sim/run	RTL simulation run scripts directory
complexpack.mk	GNU Makefile for running GHDL simulations.
run.sh	A bash script for running the GNU Makefile for GHDL.

3. complexpack usage

The complexpack package test script can be used as follows:

as run from within the ./sim/rtl_sim/run subdirectory.

After this process, the complexpack_results.txt file is generated containing simulation results.

4. Prerequisities

• Standard UNIX-based tools (tested on cygwin/x86 and MinGW/x86 and MinGW/x64)

  • make
  • bash

• GHDL simulator (http://ghdl.free.fr)

  Provides the "ghdl" executable and corresponding simulation environment. Versions throughtout 0.26 to 0.31 (mcode) have been used for testing.