Re: ALTFP_MULT and ALTFP_ADD_SUB issues

Altera_Forum · ‎04-17-2012

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 ---

Altera_Forum · ‎04-17-2012

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 · ‎06-09-2012

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 · ‎06-09-2012

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 · ‎06-10-2012

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