Subversion Repositories fixed_extensions

------------------------------------------------------------------------------
-- Title            : fixed_extensions (VHDL fixed-point arithmetic         --
--                  : extensions package).                                  --
-- Author           : Nikolaos Kavvadias                                    --
-- Contact          : nikolaos.kavvadias@gmail.com                          --
--                  : http://www.nkavvadias.com                             --
-- Release Date     : 25 July 2011                                          --
-- Version          : 0.0.5                                                 --
--------------------:---------------------------------------------------------
-- Revision history :                                                       --
--           v0.0.5 : 2011-07-25                                            --
--                  : Initial release.                                      --
------------------------------------------------------------------------------


1. INTRODUCTION
---------------

"fixed_extensions_pkg" is a fixed-point arithmetic package written in VHDL 
according to the VHDL-2008 update of the standard. It uses VHDL-2008 back-
compatible libraries (by David Bishop) that are included in this distribution 
for the sake of completeness.

Currently, the "fixed_extensions_pkg" package implements the following:

  - ceil      : round towards plus infinity.
  - fix       : round towards zero.
  - floor     : round towards minus infinity.
  - round     : round to nearest; ties to greatest absolute value.
  - nearest   : round to nearest; ties to plus infinity.
  - convergent: round to nearest; ties to closest even.
  - bitinsert : bit-field insertion to word
  - bitextract: bit-field extraction from word

"fixed_extensions" is distributed along with a tool (gentestround) to generate 
customized VHDL test designs.


2. FILE LISTING
---------------

  The fixed_extensions distributions includes the following files:

  /fixed_extensions-<version>
    /bench/vhdl
      testrounding_tb.vhd  Standard testbench file.  
    /doc
      AUTHORS              List of "fixed_extensions" authors.
      BUGS                 Bug list.
      ChangeLog            A log for code changes.
      COPYING.BSD          The Modified BSD License.
      README               This file.
      THANKS               Acknowledgements.
      TODO                 A list of future enhancements.
    /gen/vhdl
      testroundings.vhd    Auto-generated test file for sfixed arithmetic.
      testroundingu.vhd    Auto-generated test file for ufixed arithmetic.
    /rtl/vhdl
      fixed_extensions_pkg_sim.vhd
                           The VHDL package for simulation-oriented use.
      fixed_extensions_pkg_synth.vhd
                           The VHDL package for synthesis-oriented use.
    /sim/rtl_sim/bin
      run.sh               A bash script for testing the package.
      testroundings.do     Modelsim macro script for testing sfixed arithmetic.
      testroundings.sh     Bash script for running an sfixed simulation.
      testroundingu.do     Modelsim macro script for testing ufixed arithmetic.
      testroundingu.sh     Bash script for running an ufixed simulation.
    /sim/rtl_sim/src
      fixed_float_types_custom.vhd
                           VHDL package with definitions for fixed-point arith.
      fixed_pkg_c.vhd      VHDL package implementing fixed-point arithmetic.
      math_real.vhd        VHDL package with some real arithmetic functions.    
    /sw
      gentestround.c       Test design generator written in ANSI C.
      Makefile             Makefile for compiling the test design generator.


3. FIXED_EXTENSIONS USAGE
-------------------------

  The fixed_extensions package can be used as follows:
  $./run.sh


4. PREREQUISITIES
-----------------

- Standard UNIX-based tools (tested on cygwin/x86)
  make, bash
- [optional] Mentor Modelsim ("mti") (http://www.mentor.com)
  Provides a simulation environment to run the tests.


5. CONTACT
----------

You may contact me for further questions/suggestions/corrections at:

  Nikolaos Kavvadias <nkavv@physics.auth.gr>
                     <nkavv@uop.gr>
                     <nikolaos.kavvadias@gmail.com>
  http://www.nkavvadias.com