library ieee;
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-- RAYTRAC
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use ieee.std_logic_1164.all;
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-- Author Julian Andres Guarin
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-- cla_logic_block.vhd
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-- This file is part of raytrac.
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--
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-- raytrac is free software: you can redistribute it and/or modify
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-- it under the terms of the GNU General Public License as published by
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-- the Free Software Foundation, either version 3 of the License, or
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-- (at your option) any later version.
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--
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-- raytrac is distributed in the hope that it will be useful,
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-- but WITHOUT ANY WARRANTY; without even the implied warranty of
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-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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-- GNU General Public License for more details.
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--
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-- You should have received a copy of the GNU General Public License
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-- along with raytrac. If not, see <http://www.gnu.org/licenses/>.library ieee;
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-- Check out arithpack.vhd to understand in general terms what this file describes,
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-- or checkout this file to check in detailed way what this file intends to.
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use ieee.std_logic_1164.all;
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entity cla_logic_block is
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entity cla_logic_block is
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generic (
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generic (
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w : integer := 4
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w : integer := 4 -- Carry Look Ahead Block Default Size
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);
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);
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port (
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port (
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p,g : in std_logic_vector(w-1 downto 0);
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p,g : in std_logic_vector(w-1 downto 0); -- Propagation and Generation Inputs
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cin : in std_logic;
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cin : in std_logic; -- Carry In input
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c : out std_logic_vector(w downto 1)
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c : out std_logic_vector(w downto 1) -- Generated Carry Out outputs
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);
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);
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end cla_logic_block;
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end cla_logic_block;
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architecture cla_logic_block_arch of cla_logic_block is
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architecture cla_logic_block_arch of cla_logic_block is
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begin
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begin
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claProc: -- claProc instancia funciones combinatorias en las variables iCarry,
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claProc: -- claProc instancia funciones combinatorias en las variables iCarry,
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-- pero notese que los valores de iCarry(i) no dependen jamas de iCarry(i-1) a diferencia de rcaProc
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-- pero notese que los valores de iCarry(i) no dependen jamas de iCarry(i-1) a diferencia de rcaProc
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process(p,g,cin)
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process(p,g,cin)
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variable i,j,k : integer range 0 to w; -- Variables de control de loop
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variable i,j,k : integer range 0 to w; -- Variables de control de loop
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variable iCarry: std_logic_vector(w downto 1); -- Carry Interno
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variable iCarry: std_logic_vector(w downto 1); -- Carry Interno
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variable iResults: std_logic_vector(((w+w**2)/2)-1 downto 0); -- Resultados intermedios
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variable iResults: std_logic_vector(((w+w**2)/2)-1 downto 0); -- Resultados intermedios
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variable index: integer;
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variable index: integer;
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begin
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begin
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iCarry(w downto 1) := g(w-1 downto 0);
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iCarry(w downto 1) := g(w-1 downto 0);
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index := 0;
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index := 0;
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for j in 0 to w-1 loop
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for j in 0 to w-1 loop
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for i in 1 to j+1 loop
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for i in 1 to j+1 loop
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iResults(index) := '1';
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iResults(index) := '1';
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for k in j-i+1 to j loop
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for k in j-i+1 to j loop
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iResults(index) := iResults(index) and p(k);
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iResults(index) := iResults(index) and p(k);
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end loop;
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end loop;
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if j>=i then
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if j>=i then
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iResults(index) := iResults(index) and g(j-i);
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iResults(index) := iResults(index) and g(j-i);
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else
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else
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iResults(index) := iResults(index) and cin;
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iResults(index) := iResults(index) and cin;
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end if;
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end if;
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iCarry(j+1) := iCarry(j+1) or iResults(index);
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iCarry(j+1) := iCarry(j+1) or iResults(index);
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index := index + 1;
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index := index + 1;
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end loop;
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end loop;
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c(j+1) <= iCarry(j+1);
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c(j+1) <= iCarry(j+1);
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end loop;
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end loop;
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end process claProc;
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end process claProc;
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end cla_logic_block_arch;
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end cla_logic_block_arch;
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