--
-- Copyright 2021 Ettus Research, a National Instruments Brand
--
-- SPDX-License-Identifier: LGPL-3.0-or-later
--
-- Module: scale_2x
--
-- Description:
--
--   This block does the scaling of IQ data by 2. The data from the mixer is
--   1/2 the full scale and the upper two bits will only have the signed bits,
--   so it is okay to multiply the data by 2 and resize it back to 16 bits.
--
-- Parameters:
--
--   kDataWidth: Data width, should be a multiple of 16 bits.
--

library IEEE;
  use IEEE.std_logic_1164.all;
  use IEEE.numeric_std.all;

library WORK;
  use WORK.PkgRf.all;

entity scale_2x is
  generic(
    kDataWidth : integer range 1 to 256 := 32
  );
  port(
    -- [..Q1,I1,Q0,I0] (I in LSBs). Each I and Q data is 16 bits wide, but
    -- since the data is only 1/2 full scale. Useful information is only
    -- in the lower 15 bits, with upper two bits used as a signed bit.
    cDataIn          : in std_logic_vector(kDataWidth-1 downto 0);
    cDataValidIn     : in std_logic;

    -- [..Q1,I1,Q0,I0] (I in LSBs). 16 bit output with a gain of 2x.
    cDataOut         : out std_logic_vector(kDataWidth-1 downto 0);
    cDataValidOut    : out std_logic
  );
end scale_2x;

architecture RTL of scale_2x is

begin

 -- Scale the date by 2 by shifting the data to the left by 1 bit.
 cDataOut      <= Gain2x(cDataIn);
 cDataValidOut <= cDataValidIn;

end RTL;