Re: [vhdl-200x] Regarding Fixed Point Algorithmic User's Guide

From: Sharad Sinha <>
Date: Wed Oct 09 2013 - 08:21:12 PDT
Hi Jim,

  I guess that brings up the question if the package itself has been
verified and validated carefully and if so what are its limitations in
terms of accuracy of results and whether they have been quantified. The
associated documentation says: "These algorithms are not exhaustively
debugged....use at your own risk..".

  Besides, I am not sure why I would want to validate a hardware
implementation of these functions if I am using pre-verified
implementations of these in my overall design which is generally the case
in complex designs. I understand that if I do an implementation of my own,
then I would like to verify it. But do I really need to verify my
implementation this way? If verification is indeed an objective of
including such packages, then the documentation should be more rigorous
with more insight into how the package code works.

  The reason I am a bit picky about such parts of packages like these is
that it makes me feel that probably VHDL equivalent packages of BLAS,
LINPACK etc. would be better. Of course based on how packages are being
proposed now, it is possible that we can have packages for statistical
calculations and likewise.


On Wed, Oct 9, 2013 at 10:50 PM, Jim Lewis <> wrote:

> Hi Sharad,
> There are certainly more applications than just synthesis.
> The most obvious is verification.  When you create a hardware
> block that implements one of these operations, it is nice
> having a package of operators available for independent
> validation of the hardware.
> On the other hand, keep in mind that very little in numeric_std
> is actually synthesized.  Most is guided by pragmas and
> metacomments to a particular implementation.  As such having
> these functions gives users a mechanism to ask their vendors
> to implement a particular operation - and hence, provide
> a vendor independent way to achieve the functionality.
> Best Regards,
> Jim
>  Hi group,
>>    I had a look at the Fixed Point Algorithmic User's Guide. I am not
>> sure about the utility of including functions to calculate exp(), log() and
>> some trigonometric functions like sin(). The reason I
>> am not sure is that vendors, at least the FPGA ones, provide IP cores to
>> do these operations. Of course they have their own limitations etc. but
>> that is another issue.
>>   Is there really a need to include some of those functions in the
>> package? If yes, where would they find most utility? Synthesis, testbench
>> or both?
>> Regard,
>> Sharad
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Received on Wed Oct 9 08:21:50 2013

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