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Anonymous
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## Two’s Complement Multiplier with DSP48E1

Hello Everyone,

I would to know more about output on multiplier in DSP48E1.

I saw in another documentation about Two’s Complement Multiplier, when we multiply two arrays with N bits on output will have one array with width 2N and have two signed bits.

I need implement several DSP in Cascate, like it "7 Series DSP48E1 Slice" (UG479) pág. 49.

I believe that for every multiplication done I'll have a bit more than you can change the value end of my filter.

I would to know if output the multipler need these handling or this already handled by the partial products.

I maked test with DSP48E1 primitive and did not recognize the two-bit signal.

I studied "7 Series DSP48E1 Slice" (UG479), but I didn't find this information.

Sorry guys if there is already any post with this information, I lookup all forum but could not find any post that can solve my question.

It is my first post. I hope first of many.

Any help is welcome.

Best Regards,

Raphael Augusto José

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Scholar
5,047 Views
Registered: ‎02-27-2008

r,

A signd multiplier takes two signed numbers, and provides you with the signed product (answer).

Thwe DSP48 uses 2's complement signed number format.  The result is a 2's complement result.

In general, the only thing you need to decide, is how to throw away the lower part of the products, or how to form a longer sum (beyond 28 bits).

Austin Lesea
Principal Engineer
Xilinx San Jose
2 Replies
Highlighted
Scholar
5,048 Views
Registered: ‎02-27-2008

r,

A signd multiplier takes two signed numbers, and provides you with the signed product (answer).

Thwe DSP48 uses 2's complement signed number format.  The result is a 2's complement result.

In general, the only thing you need to decide, is how to throw away the lower part of the products, or how to form a longer sum (beyond 28 bits).

Austin Lesea
Principal Engineer
Xilinx San Jose
Highlighted
Anonymous
Not applicable
4,326 Views
Hello Austin,

Sorry for my delay in my reply.