Apply g_fft.out_gain_w (no functional change when g_fft.out_gain_w is 0).

libraries/dsp/fft/src/vhdl/fft_r2_par.vhd

@@ -128,9 +128,9 @@ architecture str of fft_r2_par is
   constant c_in_scale_w_tester  : integer := g_fft.stage_dat_w - g_fft.in_dat_w - sel_a_b(g_fft.guard_enable, g_fft.guard_w, 0);
   constant c_in_scale_w         : natural := sel_a_b(c_in_scale_w_tester > 0, c_in_scale_w_tester, 0);  -- Only scale when in_dat_w is not too big. 
   
-  constant c_out_scale_w_tester : integer := g_fft.stage_dat_w - g_fft.out_dat_w;                -- Estimate number of LSBs to throw away. 
+  constant c_out_scale_w_tester : integer := g_fft.stage_dat_w - g_fft.out_dat_w - g_fft.out_gain_w;    -- Estimate number of LSBs to throw away. 
   constant c_out_scale_w        : natural := sel_a_b(c_out_scale_w_tester > 0,  c_out_scale_w_tester, 0);
-  constant c_out_gain_w         : natural := sel_a_b(c_out_scale_w_tester < 0, -c_out_scale_w_tester, 0) + g_fft.out_gain_w;
+  constant c_out_gain_w         : natural := sel_a_b(c_out_scale_w_tester < 0, -c_out_scale_w_tester, 0);
   
   type   t_stage_dat_arr   is array (integer range <>)     of std_logic_vector(g_fft.stage_dat_w-1 downto 0);
   type   t_stage_sum_arr   is array (integer range <>)     of std_logic_vector(g_fft.stage_dat_w   downto 0);

libraries/dsp/fft/src/vhdl/fft_r2_pipe.vhd

@@ -79,9 +79,9 @@ architecture str of fft_r2_pipe is
   constant c_nof_stages         : natural := ceil_log2(g_fft.nof_points);
   constant c_stage_offset       : natural := true_log2(g_fft.wb_factor);                         -- Stage offset is required for twiddle generation in wideband fft
   constant c_in_scale_w         : natural := g_fft.stage_dat_w - g_fft.in_dat_w - sel_a_b(g_fft.guard_enable, g_fft.guard_w, 0);              
-  constant c_out_scale_w_tester : integer := g_fft.stage_dat_w - g_fft.out_dat_w;                -- Estimate number of LSBs to throw away. 
+  constant c_out_scale_w_tester : integer := g_fft.stage_dat_w - g_fft.out_dat_w - g_fft.out_gain_w;  -- Estimate number of LSBs to throw away. 
   constant c_out_scale_w        : natural := sel_a_b(c_out_scale_w_tester > 0,  c_out_scale_w_tester, 0);
-  constant c_out_gain_w         : natural := sel_a_b(c_out_scale_w_tester < 0, -c_out_scale_w_tester, 0) + g_fft.out_gain_w;
+  constant c_out_gain_w         : natural := sel_a_b(c_out_scale_w_tester < 0, -c_out_scale_w_tester, 0);
 
   -- number the stage instances from c_nof_stages:1
   -- . the data input for the first stage has index c_nof_stages

libraries/dsp/fft/src/vhdl/fft_r2_wide.vhd

@@ -92,7 +92,7 @@ architecture rtl of fft_r2_wide is
       v_return(I).nof_points     := v_nof_points;      -- Set the nof points 
       v_return(I).in_dat_w       := input.stage_dat_w; -- Set the input width  
       v_return(I).out_dat_w      := input.stage_dat_w; -- Set the output width. 
-      v_return(I).out_gain_w     := 0;                 -- Output gain is forced to 0 for pipeline FFT, because it is taken care of in parallel FFT
+      v_return(I).out_gain_w     := 0;                 -- Output gain is forced to 0
       v_return(I).guard_w        := 0;                 -- Set the guard_w to 0 to enable scaling at every stage. 
       v_return(I).guard_enable   := false;             -- No input guard. 
     end loop;                               
@@ -112,20 +112,20 @@ architecture rtl of fft_r2_wide is
       v_return.nof_points     := input.wb_factor;   -- Set the number of points to wb_factor
       v_return.in_dat_w       := input.stage_dat_w; -- Specify the input width
       v_return.out_dat_w      := input.stage_dat_w; -- Output width 
-      v_return.out_gain_w     := input.out_gain_w;  -- Output gain
+      v_return.out_gain_w     := 0;                 -- Output gain is forced to 0, because it is taken care of outside parallel fft
       v_return.guard_w        := input.guard_w;     -- Set the guard_w here to skip the scaling on the last stages
       v_return.guard_enable   := false;             -- No input guard. 
     return v_return; 
   end;
   
-  constant c_fft_r2_par       : t_fft   := func_create_generic_for_par_fft(g_fft);
   constant c_fft_r2_pipe_arr  : t_fft_arr(g_fft.wb_factor-1 downto 0) := func_create_generic_for_pipe_fft(g_fft); 
+  constant c_fft_r2_par       : t_fft                                 := func_create_generic_for_par_fft(g_fft);
   
   constant c_in_scale_w       : natural := g_fft.stage_dat_w - g_fft.in_dat_w - sel_a_b(g_fft.guard_enable, g_fft.guard_w, 0);              
   
-  constant c_out_scale_w_tester : integer := c_fft_r2_par.out_dat_w - g_fft.out_dat_w;                -- Estimate number of LSBs to throw away. 
+  constant c_out_scale_w_tester : integer := c_fft_r2_par.out_dat_w - g_fft.out_dat_w - g_fft.out_gain_w;  -- Estimate number of LSBs to throw away. 
   constant c_out_scale_w        : natural := sel_a_b(c_out_scale_w_tester > 0,  c_out_scale_w_tester, 0);
-  constant c_out_gain_w         : natural := sel_a_b(c_out_scale_w_tester < 0, -c_out_scale_w_tester, 0) + c_fft_r2_par.out_gain_w;
+  constant c_out_gain_w         : natural := sel_a_b(c_out_scale_w_tester < 0, -c_out_scale_w_tester, 0);
 
   signal in_fft_pipe_re_arr   : t_fft_slv_arr(g_fft.wb_factor-1 downto 0);
   signal in_fft_pipe_im_arr   : t_fft_slv_arr(g_fft.wb_factor-1 downto 0);