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davidklun |
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---- ----
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---- FPU ----
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---- Floating Point Unit (Double precision) ----
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---- ----
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---- Author: David Lundgren ----
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---- davidklun@gmail.com ----
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---- ----
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---------------------------------------------------------------------
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---- ----
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---- Copyright (C) 2009 David Lundgren ----
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---- davidklun@gmail.com ----
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---- ----
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---- This source file may be used and distributed without ----
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---- restriction provided that this copyright statement is not ----
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---- removed from the file and that any derivative work contains ----
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---- the original copyright notice and the associated disclaimer.----
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---- ----
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---- THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY ----
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---- EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED ----
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---- TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS ----
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---- FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL THE AUTHOR ----
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---- OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, ----
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---- INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES ----
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---- (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE ----
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---- GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR ----
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---- BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF ----
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---- LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT ----
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---- (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT ----
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---- OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE ----
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---- POSSIBILITY OF SUCH DAMAGE. ----
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---- ----
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---------------------------------------------------------------------
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library ieee;
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use ieee.std_logic_1164.all;
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use ieee.std_logic_unsigned.all;
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package fpupack is
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-- count the number of zeros starting from the left
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function count_l_zeros (signal s_vector: std_logic_vector) return std_logic_vector;
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function count_zeros_mul (signal s_vector: std_logic_vector) return std_logic_vector;
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end fpupack;
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package body fpupack is
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function count_l_zeros (signal s_vector: std_logic_vector) return std_logic_vector is
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variable v_count : std_logic_vector(5 downto 0);
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begin
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v_count := "000000";
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for i in s_vector'range loop
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case s_vector(i) is
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when '0' => v_count := v_count + "000001";
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when others => exit;
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end case;
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end loop;
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return v_count;
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end count_l_zeros;
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-- count the zeros from the left for multiply
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function count_zeros_mul (signal s_vector: std_logic_vector) return std_logic_vector is
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variable v_count : std_logic_vector(5 downto 0);
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begin
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v_count := "000000";
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for i in 105 downto 52 loop
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case s_vector(i) is
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when '0' => v_count := v_count + "000001";
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when others => exit;
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end case;
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end loop;
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return v_count;
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end count_zeros_mul;
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end fpupack;
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