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Altera_Forum's avatar
Altera_Forum
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14 years ago

VHDL code for logarithme

Hi, There are somoene that release a vhdl code for log or have any idea about it. I need any tutorial or helps to start release it. Thank you.
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
14 years ago

like log base 2?

this function will return the nearest log2 of a number (but I wouldnt recommend synthesising as a real time function) Its useful for determining how many bits you need for a vector. 


function log2(x : integer) return integer is
  variable temp : integer :=x;
  variable n : integer := 1;
begin
  while temp > 1 loop
    temp := temp/2;
    n := n + 1;
  end loop;
 
  return n;
end function log2;