------------------------------------------------
|
------------------------------------------------
|
--! @file RLshifter.vhd
|
--! @file RLshifter.vhd
|
--! @brief RayTrac Arithmetic Shifter
|
--! @brief RayTrac Arithmetic Shifter
|
--! @author Julián Andrés Guarín Reyes
|
--! @author Julián Andrés Guarín Reyes
|
--------------------------------------------------
|
--------------------------------------------------
|
|
|
|
|
-- RAYTRAC
|
-- RAYTRAC
|
-- Author Julian Andres Guarin
|
-- Author Julian Andres Guarin
|
-- RLshifter.vhd
|
-- RLshifter.vhd
|
-- This file is part of raytrac.
|
-- This file is part of raytrac.
|
--
|
--
|
-- raytrac is free software: you can redistribute it and/or modify
|
-- raytrac is free software: you can redistribute it and/or modify
|
-- it under the terms of the GNU General Public License as published by
|
-- it under the terms of the GNU General Public License as published by
|
-- the Free Software Foundation, either version 3 of the License, or
|
-- the Free Software Foundation, either version 3 of the License, or
|
-- (at your option) any later version.
|
-- (at your option) any later version.
|
--
|
--
|
-- raytrac is distributed in the hope that it will be useful,
|
-- raytrac is distributed in the hope that it will be useful,
|
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
|
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
|
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
-- GNU General Public License for more details.
|
-- GNU General Public License for more details.
|
--
|
--
|
-- You should have received a copy of the GNU General Public License
|
-- You should have received a copy of the GNU General Public License
|
-- along with raytrac. If not, see <http://www.gnu.org/licenses/>
|
-- along with raytrac. If not, see <http://www.gnu.org/licenses/>
|
|
|
|
|
library ieee;
|
library ieee;
|
use ieee.std_logic_1164.all;
|
use ieee.std_logic_1164.all;
|
use ieee.std_logic_arith.all;
|
use ieee.std_logic_arith.all;
|
use ieee.std_logic_unsigned.all;
|
use ieee.std_logic_unsigned.all;
|
use ieee.math_real.all;
|
use ieee.math_real.all;
|
|
|
|
|
|
|
|
|
entity RLshifter is
|
entity RLshifter is
|
generic (
|
generic (
|
shiftFunction : string := "SQUARE_ROOT";
|
shiftFunction : string := "SQUARE_ROOT";
|
mantissa_width : integer := 18;
|
mantissa_width : integer := 18;
|
iwidth : integer := 32;
|
iwidth : integer := 32;
|
owidth : integer := 16
|
owidth : integer := 16
|
|
|
);
|
);
|
port (
|
port (
|
exp : in std_logic_vector (integer(ceil(log(real(iwidth),2.0)))-1 downto 0);
|
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);
|
mantis : in std_logic_vector (mantissa_width-1 downto 0);
|
result : out std_logic_vector (owidth-1 downto 0)
|
result : out std_logic_vector (owidth-1 downto 0)
|
);
|
);
|
end RLshifter;
|
end RLshifter;
|
|
|
|
|
architecture RLshifter_arch of RLshifter is
|
architecture RLshifter_arch of RLshifter is
|
begin
|
begin
|
|
|
inverse:
|
inverse:
|
process (mantis,exp)
|
process (mantis,exp)
|
variable expi : integer ;
|
variable expi : integer ;
|
begin
|
begin
|
if shiftFunction="INVERSION" then
|
if shiftFunction="INVERSION" then
|
expi:= conv_integer(exp);
|
expi:= conv_integer(exp);
|
else
|
else
|
expi:= conv_integer(exp(exp'high downto 1));
|
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)
|
end if;
|
end if;
|
|
|
for i in owidth-1 downto 0 loop
|
for i in owidth-1 downto 0 loop
|
|
|
result(i)<='0';
|
result(i)<='0';
|
|
|
if shiftFunction="INVERSION" then
|
if shiftFunction="INVERSION" then
|
if i<=owidth-1-expi and i>=owidth-expi-mantissa_width then
|
if i<=owidth-1-expi and i>=owidth-expi-mantissa_width then
|
result(i)<=mantis(mantissa_width-owidth+expi+i);
|
result(i)<=mantis(mantissa_width-owidth+expi+i);
|
end if;
|
end if;
|
end if;
|
end if;
|
|
|
if shiftFunction="SQUARE_ROOT" then
|
if shiftFunction="SQUARE_ROOT" then
|
if i<=expi then
|
if i<=expi then
|
result(i)<=mantis(mantissa_width-1-expi+i);
|
result(i)<=mantis(mantissa_width-1-expi+i);
|
end if;
|
end if;
|
end if;
|
end if;
|
|
|
end loop;
|
end loop;
|
|
|
end process inverse;
|
end process inverse;
|
|
|
end RLshifter_arch;
|
end RLshifter_arch;
|
|
|
|
|
