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Comp.Arch.FPGA | Xilinx multiplier out of slices

There are 5 messages in this thread.

You are currently looking at messages 0 to 5.

Xilinx multiplier out of slices - Peter Sommerfeld - 2005-04-22 17:16:00

Hi,

I'm new to the Xilinx tools. How do I tell Xilinx ISE 7.1 to synthesise
the following statement:

y <= a * b;

to NOT use dedicated multipliers?

Thanks a bunch, Pete



Re: Xilinx multiplier out of slices - Symon - 2005-04-22 20:14:00

Pete,
Synplify uses an attribute called syn_multsyle. I know this doesn't answer
your question but it might help in your google searches?
Good luck, Syms.
"Peter Sommerfeld" <p...@gmail.com> wrote in message
news:1...@z14g2000cwz.googlegroups.com...
> Hi,
>
> I'm new to the Xilinx tools. How do I tell Xilinx ISE 7.1 to synthesise
> the following statement:
>
> y <= a * b;
>
> to NOT use dedicated multipliers?
>
> Thanks a bunch, Pete
>
______________________________
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Re: Xilinx multiplier out of slices - Ken McElvain - 2005-04-22 21:09:00

Synplify counts the number of multiplier uses and
and if
you overflow the available resources, then it puts the
smaller mults into the logic fabric.   So you do not
normally need to use the syn_multstyle attribute.   If you
are doing bottom up design there is an available resources
attribute that lets you set the budgets for your block.

Ken McElvain
Synplicity, Inc.


Symon wrote:

> Pete,
> Synplify uses an attribute called syn_multsyle. I know this doesn't answer
> your question but it might help in your google searches?
> Good luck, Syms.
> "Peter Sommerfeld" <p...@gmail.com> wrote in message
> news:1...@z14g2000cwz.googlegroups.com...
> 
>>Hi,
>>
>>I'm new to the Xilinx tools. How do I tell Xilinx ISE 7.1 to synthesise
>>the following statement:
>>
>>y <= a * b;
>>
>>to NOT use dedicated multipliers?
>>
>>Thanks a bunch, Pete
>>
> 
> 
>
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Re: Xilinx multiplier out of slices - Brian Drummond - 2005-04-23 07:13:00

On 22 Apr 2005 14:16:31 -0700, "Peter
Sommerfeld"
<p...@gmail.com> wrote:

>Hi,
>
>I'm new to the Xilinx tools. How do I tell Xilinx ISE 7.1 to synthesise
>the following statement:
>
>y <= a * b;
>
>to NOT use dedicated multipliers?
>

Attribute mult_style:String;
Attribute mult_style of y : signal is "lut";

(I believe you can apply the attribute to component or label names too)

- Brian
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Re: Xilinx multiplier out of slices - Jerzy Gbur - 2005-04-23 10:44:00

Hello
> 
> I'm new to the Xilinx tools. How do I tell Xilinx ISE 7.1 to synthesise
> the following statement:
> 
> y <= a * b;
> 
> to NOT use dedicated multipliers?

If you have coregen, use it for generate multiplier core and set it, not
to use multipliers. If you haven't mhm... 

Jerzy Gbur