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[/] [raytrac/] [trunk/] [sqrtdiv/] [shift.vhd] - Rev 104
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------------------------------------------------ --! @file shift.vhd --! @brief RayTrac TestBench --! @author Julián Andrés Guarín Reyes -------------------------------------------------- -- RAYTRAC -- Author Julian Andres Guarin -- shift.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_signed.all; use ieee.math_real.all; --! \brief Dado que cualquier número entero A, se puede escribir 2^n * f, es importante obtener una representación del valor de f en base 2. Una vez hallado este valor y evaluado en una función bastara con realizar un corrimiento a la izquierda n bits del resultado, para calcular funciones como A^-1 o A^0.5. entity shifter is generic ( address_width : integer := 9; width : integer := 32; --! Cuando even shifter es "YES" se hara la busqueda del primer bit con valor 1, de izquierda a derecha, pero NO de uno en uno. even_shifter : string := "YES" ); port ( data : in std_logic_vector(width - 1 downto 0); exp : out std_logic_vector(integer(ceil(log(real(width),2.0)))-1 downto 0); address : out std_logic_vector (address_width-1 downto 0); zero : out std_logic ); end shifter; architecture shifter_arch of shifter is begin sanityLost: process (data) variable index: integer range-1 to width+address_width-1:=width+address_width-1; begin address<=(others=>'0'); exp<=(others=>'0'); zero<=data(0); if even_shifter="YES" then index:=width-1; else index:=width-2; end if; while index>=1 loop if data(index)='1' then zero<='0'; exp<=CONV_STD_LOGIC_VECTOR(index, exp'high+1); if index>=address_width then address <= data (index-1 downto index-address_width); else address(address_width-1 downto address_width-index) <= data (index-1 downto 0); address(address_width-index-1 downto 0) <= (others =>'0'); end if; exit; end if; index:=index-2; --Boost end loop; end process sanityLost; end shifter_arch;
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