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Altera_Forum
Honored Contributor I
925 Views

ALTFP_MULT and ALTFP_ADD_SUB issues

Hi there, 

 

When I simulate the ALTFP_MULT and ALTFP_ADD_SUB megafunctions in modelsim (directly from my testbench, not through my main design) I get zero results from both. Has anyone else encountered this, or perhaps have any ideas why this might be happening? 

 

I'm using this code to simulate them: 

 

 

--- Quote Start ---  

 

FIRadd addtest( 

add_rst, 

add_en, 

CLOCK_50, 

dataa, 

datab, 

add_result 

); 

 

initial 

begin 

add_rst = 1'b1; 

add_en = 1'b0; 

dataa = 32'h00000000; 

datab = 32'h00000000; 

# 50ns; 

add_rst = 1'b0; 

add_en = 1'b1; 

dataa = 32'h0000000F; 

datab = 32'h0000F001; 

end 

 

 

--- Quote End ---  

0 Kudos
4 Replies
Altera_Forum
Honored Contributor I
46 Views

Solved - parts of these megafunctions were being synthesised away, as the registers driving them (in my actual design) weren't driving them properly.

Altera_Forum
Honored Contributor I
46 Views

jacki2ya, I am having the same problem and you wrote here as solved but I could not understand how you solved. Please, could you write how you solve it?

Altera_Forum
Honored Contributor I
46 Views

My fix was fairly design specific. That is, I fixed a part of my design that drove these units and then they started synthesising properly. 

 

As it was a little while back, the most I remember it being was that the registers that drove my ALTFP_MULT (which then fed the adders) were incorrectly specified. Once I fixed this small issue, everything else fell into place. 

 

I wish I could give more information then that. I wish you the best of luck though, I know how frustrating it is!
Altera_Forum
Honored Contributor I
46 Views

Thank you jacki2ya. My problem was the same as yours. I solved it as well. Thanks.

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