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-   -   synthesis question of fixed point library (http://www.velocityreviews.com/forums/t668855-synthesis-question-of-fixed-point-library.html)

sanborne 02-04-2009 09:59 PM

synthesis question of fixed point library
 
I am having a problem synthesizing a design where I utilized David
Bishop's fixed point library extensively. There might be 2 causes to
this problem and I am hoping there is someone out there who can help.

First of all I am using the Xilinx 10.1 webpack. I am not sure if the
fixed point library will work with this free synthesis tool. I could
get a commercial license if necessary, but I have not read in any of
the documentation where it explicitly states that I need the
commercial product.

Second, I am wondering if I am attempting to synthesize the wrong
file. The error that I am getting is "HDLParsers:1014 - "//infnas-00-
ah/slittle/Projects/redesign/custom_vhdl/zigg_synth/
standard_additions_c.vhdl" Line 1884. Allocators unsupported." I did a
search in this newsgroup for the above error, and I found a thread
that seems to indicate that "allocators" are the VHDL equivalent of
dynamic memory allocation, which is impossible in hardware synthesis.
So the question is what should I do? Is there another version of
"standard_additions_c.vhdl" that I should be using? Where could I get
that a copy of the fixed point library that is synthesizable? I
suspect that I would need a whole different library, because if
"standard_additions_c.vhdl" has a synthesis error, then the other
files that I am referencing will also.

Is there another reason that I might be getting this error? I
appreciate any insight.

SY

sanborne 03-03-2009 06:55 PM

Re: synthesis question of fixed point library
 
On Feb 4, 10:29*pm, "KJ" <kkjenni...@sbcglobal.net> wrote:
> "sanborne" <sanbo...@fastmail.fm> wrote in message
>
> news:f9e0f6fe-47f8-4b82-b785-a37d882d0e4a@t26g2000prh.googlegroups.com...
>
> > First of all I am using the Xilinx 10.1 webpack. I am not sure if the
> > fixed point library will work with this free synthesis tool.

>
> Xilinx didn't used to support negative indices for vectors which are
> required in order to implement the fixed point lib stuff since negative
> indices are used for the 'fractional' part of the representation. *I've
> heard Xilinx will be supporting it and maybe 10.1 does.
>
>
>
> > Second, I am wondering if I am attempting to synthesize the wrong
> > file. The error that I am getting is "HDLParsers:1014 - "//infnas-00-
> > ah/slittle/Projects/redesign/custom_vhdl/zigg_synth/
> > standard_additions_c.vhdl" Line 1884. Allocators unsupported." I did a
> > search in this newsgroup for the above error, and I found a thread
> > that seems to indicate that "allocators" are the VHDL equivalent of
> > dynamic memory allocation, which is impossible in hardware synthesis.

>
> For the fixed point package you only need the files 'fixed_pkg_c.vhdl' and
> 'math_utility_pkg.vhdl' source files. *The file 'standard_additions_c.vhdl'
> does have allocators, it is not synthesizable, but you shouldn't need to use
> it either. *Per the comments in the 'standard_additions_c.vhdl' file...
> -- "standard_additions" package contains the additions to the built in
> -- "standard.std" package. *In the final version this package will be
> implicit.
> -- *Created for VHDL-200X par, David Bishop (dbis...@vhdl.org)
>
> But if you peruse the source file 'fixed_pkg_c.vhdl' you'll see that the
> only other package dependencies are:
> -- use ieee.std_logic_1164.all;
> -- use ieee.numeric_std.all;
> -- use ieee_proposed.math_utility_pkg.all;
> -- use ieee_proposed.fixed_pkg.all;
>
> > So the question is what should I do?

>
> Don't use that file for synthesis, it is not needed to implement fixed
> point.
>
> Kevin Jennings


Ok, this is really frustrating. I finally was able to get access to
Synplify-Pro (version 8.6.2), thinking that after all the issues I had
with Xilinx, I would finally be able to synthesize my project. But
there seem to be compilation errors in Synplify! I have searched this
group, and I am definitely not the only person who has had this
problem, but no one has posted an answer this question. See:
http://groups.google.com/group/comp....38601448b04a5a
http://groups.google.com/group/comp....d7f8ae3fa069e2

I am new to using Synplicity products, and maybe I am doing something
terribly and trivially wrong, but I sure can't figure out what the
problem is...

Steps:

1) Downloaded the Synplicity version of the fixed point library from:
http://www.eda-stds.org/fphdl/synplicity.zip

2) Create a new project in Synplify and load my VHDL files.
I set my top level entity name under Options->Configure VHDL Compiler,
and select the VHDL tab.

3) Add the following files from the downloaded Synplicity library:
math_utility_pkg_c.vhdl
fixed_pkg_c.vhdl

The files above are set to the library ieee_proposed using the Project-
>Set VHDL Library option.


4) When compiling the project, I get the following compilation errors
(copied from the compilation log file):
@I:: "H:\Projects\redesign\custom_vhdl\synplicity_fp\fi xed_pkg_c.vhdl"
@E: CD415 :"H:\Projects\redesign\custom_vhdl\synplicity_f p
\fixed_pkg_c.vhdl":1164:61:1164:61|Expecting keyword return
@E: CD428 :"H:\Projects\redesign\custom_vhdl\synplicity_f p
\fixed_pkg_c.vhdl":1460:21:1460:21|Duplicate definition of package
fixed_pkg
@E: CD200 :"H:\Projects\redesign\custom_vhdl\synplicity_f p
\fixed_pkg_c.vhdl":8086:4:8086:13|Misspelled variable, signal or
procedure name?
@E: CD415 :"H:\Projects\redesign\custom_vhdl\synplicity_f p
\fixed_pkg_c.vhdl":8607:26:8607:26|Expecting keyword is
4 errors parsing file H:\Projects\redesign\custom_vhdl\synplicity_fp
\fixed_pkg_c.vhdl

This is going to be a huge bummer if I cannot get this code to
synthesize. I would really appreciate any pointers from anyone.

Thanks,

SY

Mike Treseler 03-03-2009 10:51 PM

Re: synthesis question of fixed point library
 
sanborne wrote:

> @E: CD428 :"H:\Projects\redesign\custom_vhdl\synplicity_f p
> \fixed_pkg_c.vhdl":1460:21:1460:21|Duplicate definition of package
> fixed_pkg


Sounds like you included code for fixed_pkg twice,
or synplicity already knows about it.

-- Mike Treseler

sanborne 03-04-2009 02:12 PM

Re: synthesis question of fixed point library
 
On Mar 3, 5:51*pm, Mike Treseler <mtrese...@gmail.com> wrote:
> sanborne wrote:
> > @E: CD428 :"H:\Projects\redesign\custom_vhdl\synplicity_f p
> > \fixed_pkg_c.vhdl":1460:21:1460:21|Duplicate definition of package
> > fixed_pkg

>
> Sounds like you included code for fixed_pkg twice,
> or synplicity already knows about it.
>
> * * *-- Mike Treseler


So I figured out the problem. I updated to Synplify 9.6.2, and the
design synthesized successfully.

Is it normal that there are 62 warnings produced in the
fixed_pkg_c.vhdl file? I have learned not to just ignore warnings when
synthesizing hardware.

SY

Mike Treseler 03-04-2009 05:33 PM

Re: synthesis question of fixed point library
 
sanborne wrote:

> So I figured out the problem. I updated to Synplify 9.6.2, and the
> design synthesized successfully.


Did it sim successfully?

> Is it normal that there are 62 warnings produced in the
> fixed_pkg_c.vhdl file?


Like you said, you may be the first to have tried this.
Talk to the package author, and to the synthesis vendor.

-- Mike Treseler


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