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synthesis of ieee.math_in Vivado

Posts: 14
Registered: ‎01-26-2010

synthesis of ieee.math_in Vivado

I use a function to calculate some sinus values into the RAM for filter coefficients. THese are static values.


Vivado miss the ieee.math_real library. I have read the satic use is possible.


How can I set up correctly?

Posts: 1,779
Registered: ‎06-24-2013

Re: synthesis of ieee.math_in Vivado

Hey @doss,


Something like this should do the trick:

library IEEE;
use IEEE.std_logic_1164.ALL;
use IEEE.numeric_std.ALL;
use IEEE.math_real.ALL;

constant AWIDTH : integer := 8; constant DWIDTH : integer := 32; constant MDEPTH : integer := 2**AWIDTH; type mem_t is array (0 to MDEPTH-1) of signed(DWIDTH-1 downto 0); function init_mem return mem_t is constant SCALE : real := 2**(real(DWIDTH-2)); constant STEP : real := 1.0/real(MDEPTH); variable mem : mem_t; begin for I in 0 to MDEPTH-1 loop mem(I) := to_signed(integer(
cos(2.0*MATH_PI*real(I)*STEP)*SCALE), DWIDTH); end loop; return mem; end; constant sin : mem_t := init_mem;

Hope this helps,


-------------- Yes, I do this for fun!
Posts: 292
Registered: ‎04-26-2012

Re: synthesis of ieee.math_in Vivado

[ Edited ]

@doss "Vivado miss the ieee.math_real library."


 Vivado synthesis *DOES* suppport ieee.math_real for elaboration-time calculations, but unfortunately:

   - the online syntax checker in the VIvado editor mistakenly flags ieee.math_real as an error

   - some Xilinx documentation mistakenly claims ieee.math_real is unsupported


See these posts for more info and documentation links: