division.division_arc Architecture Reference

Division by constant power of two. More...

Inheritance diagram for division.division_arc:

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Collaboration diagram for division.division_arc:

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List of all members.

Functions
integer	safe_div ( A: in integer )
	make sure divisor is a power of two
Processes
div	( CLK )
	Division.
Constants
c_divisor	integer := safe_div ( DIVISOR )
	divisor

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Detailed Description

Division by constant power of two.

This entity divides an unsigned input of 14 bits by a constant that needs to be a power of two (otherwise XST can't infer a division by arithmetic shift). Output value is latched.

Definition at line 52 of file division.vhd.

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Member Function Documentation

[Process]

div

( CLK )

Division.

Definition at line 84 of file division.vhd.

  div : process (CLK)
  begin  -- process div
    if CLK'event and CLK = '1' then     -- rising clock edge
      if RES = '1' then
        C <= (others => '0');
      else
        C <= A / c_divisor;
      end if;
    end if;
  end process div;

[Function]

integer safe_div

( A in integer )

make sure divisor is a power of two

Definition at line 55 of file division.vhd.

  function safe_div (
    A : integer)
    return integer is
    variable Ai  : integer;
    variable ret : integer := 2;
  begin  -- safe_div
    Ai := A;
    while 0 < 1 loop
      if Ai < 2 then
        ret := 2;
        exit;
      else
        if Ai mod 2 /= 0 then
          Ai := Ai - 1;
        else
          ret := Ai;
          exit;
        end if;
      end if;
    end loop;
    return ret;
  end safe_div;

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Member Data Documentation

c_divisor integer := safe_div ( DIVISOR ) [Constant]

divisor

Definition at line 79 of file division.vhd.

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The documentation for this class was generated from the following file:

• division.vhd