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RE: [oc] Any using VHDL procedures with Xilinx Webpack?
Peter Ashenden's book "The Designers guide to VHDL" 1st Edition discusses
Impure and Pure Functions.
There is an example of a Impure Function on Page 213. The reason the
Function is Impure appears to
be that the Function creates a Variable inside the function that is of the
same type of Variable
Declared in the "Parent" Process. The Process that contains the Function.
Gary Olson
-----Original Message-----
From: Paul McFeeters [mailto:paul.mcfeeters@ntlworld.com]
Sent: Thursday, December 06, 2001 5:52 PM
To: cores@opencores.org
Subject: RE: [oc] Any using VHDL procedures with Xilinx Webpack?
Jim,
if it is a recursion then I can't see it. Each procedure is literally just
around 5 lines each "pin <= value" format, no special procedure/function
calls at all. One procedure does have a "if param = value then -- else --
end if" statement and uses an alias to reference the low byte in a word but
nothing more than that, definitely nothing I would even suspect as 'a little
dodgy'. All of these statements in their current form were used fine in the
expanded code so still clueless as to why Webpack should bomb.
Okay, I've changed the procedures to functions each returning a bit value
(fixed value of '1') which I just use for conditional execution of the
following statement. It complained that both functions were not "PURE" so I
had to but "IMPURE" in front of each function definition but even then
Webpack still bombs with its out of memory error same as before.
I can't find anything on PURE/IMPURE functions in any of my VHDL reference
material so if anybody knows what it means please let me know. Does anybody
know if its say 'illegal to use procedure/function calls in clock sensitive
functions' perhaps? Now I'm really fishing. I may try keeping the clocked
state_machine loop but creating a process that is sensitive to the
state_machine signal. Thus when the clock changes the state_machine it will
trigger my new process and a case loop in there can call the pin
assignments.
Failing that desperate stab in the dark I may look at putting the
procedures/functions into a separate component/library and using that method
instead but for now its time for a few hours of reading all 268 pages of the
Handel-C language manual to see if this dog really does hunt. ;-))
Paul
"If ignorance is bliss why am I not happy?"
-----Original Message-----
From: owner-cores@opencores.org [mailto:owner-cores@opencores.org]On
Behalf Of Jim Dempsey
Sent: 06 December 2001 15:28
To: cores@opencores.org
Subject: Re: [oc] Any using VHDL procedures with Xilinx Webpack?
When this type of thing happens to a C/C++ program one of the common
culprits is caused by a recursion in #include files. Might this be happening
with your modifications?
Jim Dempsey
----- Original Message -----
From: "Paul McFeeters" <paul.mcfeeters@ntlworld.com>
To: <cores@opencores.org>
Sent: Thursday, December 06, 2001 1:52 AM
Subject: [oc] Any using VHDL procedures with Xilinx Webpack?
> Hi,
>
> I seem to have run into a strange problem with the Xilinx webpack and was
> just wondering if anybody had encountered/beaten it. My VHDL module
compiled
> fine, it wasn't the prettiest module around so I decided to move some
> repetitive code into procedures just to make it more readable. Then the
fun
> started, Xilinx Webpack now says:
>
> ERROR:Portability:3 - This Xilinx application has run out of memory or has
> encountered a memory conflict. Current memory usage is 25856 kb. Memory
> problems may require a simple increase in available system memory, or
> possibly a fix to the software or a special workaround. To troubleshoot
or
> remedy the problem, first: Try increasing your system's RAM.
> Alternatively, you may try increasing your system's virtual memory or swap
> space. If this does not fix the problem, please try the following:
Search
> the Answers Database at support.xilinx.com to locate information on this
> error message. If neither of the above resources produces an available
> solution, please use Web Support to open a case with Xilinx Technical
> Support off of support.xilinx.com. As it is likely that this may be an
> unforeseen problem, please be prepared to submit relevant design files if
> necessary.
>
> Ah ha I say, I'll try compiling it under Win2k instead of 98 as it has
> better memory management (doesn't penalise when you use more than 128MB
> physical memory). So I install Webpack under Win2k on a PC and run it with
> exactly the same project so now the error is:
>
> FATAL_ERROR:Xst:Portability/export/Port_Main.h:116:1.9 - This application
> has discovered an exceptional condition from which
> it cannot recover.Process will terminate. To resolve this error, please
> consult the Answers Database and other online resources at
> http://support.xilinx.com
>
> I've looked at support.xilinx.com but would rather understand why exactly
> the same instructions but just rearranged as little 5 line procedures
should
> be so explosive to Xilinx software. I'm just off to try converting them to
> functions (fingers crossed) as a work-around but thought I would check to
> see what others more proficient in VHDL had encountered in the past. Also
> maybe a procedure inside a component would work better? If all ease fails
> then I'll see about downloading a service pack but would rather
investigate
> the error first than simply patch it and forget it. Probably the decade I
> spent as a professional programmer rubbing off.
>
> Thanks in advance
>
> Paul McFeeters
> mailto:paul.mcfeeters@ntlworld.com
>
>
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