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[/] [raytrac/] [trunk/] [sqrtdiv/] [RLshifter.vhd] - Rev 105
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------------------------------------------------ --! @file RLshifter.vhd --! @brief RayTrac Arithmetic Shifter --! @author Julián Andrés Guarín Reyes -------------------------------------------------- -- RAYTRAC -- Author Julian Andres Guarin -- RLshifter.vhd -- This file is part of raytrac. -- -- raytrac is free software: you can redistribute it and/or modify -- it under the terms of the GNU General Public License as published by -- the Free Software Foundation, either version 3 of the License, or -- (at your option) any later version. -- -- raytrac is distributed in the hope that it will be useful, -- but WITHOUT ANY WARRANTY; without even the implied warranty of -- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -- GNU General Public License for more details. -- -- You should have received a copy of the GNU General Public License -- along with raytrac. If not, see <http://www.gnu.org/licenses/> library ieee; use ieee.std_logic_1164.all; use ieee.std_logic_arith.all; use ieee.std_logic_unsigned.all; use ieee.math_real.all; entity RLshifter is generic ( shiftFunction : string := "SQUARE_ROOT"; mantissa_width : integer := 18; iwidth : integer := 32; owidth : integer := 16 ); port ( exp : in std_logic_vector (integer(ceil(log(real(iwidth),2.0)))-1 downto 0); mantis : in std_logic_vector (mantissa_width-1 downto 0); result : out std_logic_vector (owidth-1 downto 0) ); end RLshifter; architecture RLshifter_arch of RLshifter is begin inverse: process (mantis,exp) variable expi : integer ; begin expi:= conv_integer(exp(exp'high downto 1)); --! Por qu'e hasta 1 y no hasta 0!? Porque el corrimiento de la raiz cuadrada es 2^(N/2) for i in owidth-1 downto 0 loop result(i)<='0'; if shiftFunction="INVERSION" then if i<=owidth-1-expi and i>=owidth-expi-mantissa_width then result(i)<=mantis(mantissa_width-owidth+expi+i); end if; end if; if shiftFunction="SQUARE_ROOT" then if i<=expi then result(i)<=mantis(mantissa_width-1-expi+i); end if; end if; end loop; end process inverse; end RLshifter_arch;
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