diff --git a/libraries/dsp/fft/src/vhdl/fft_pkg.vhd b/libraries/dsp/fft/src/vhdl/fft_pkg.vhd
index 987eeadf40aac6e6623f578ea1bfdb457944bee9..2649fcc8d6b9b6b46f6889e2440e3b9822be2490 100644
--- a/libraries/dsp/fft/src/vhdl/fft_pkg.vhd
+++ b/libraries/dsp/fft/src/vhdl/fft_pkg.vhd
@@ -67,9 +67,9 @@ package body fft_pkg is
   function fft_r2_parameter_asserts(g_fft : t_fft) return boolean is
   begin
     -- nof_points
-    assert g_fft.nof_points=2**ceil_log2(g_fft.nof_points) report "fft_r2: nof_points must be a power of 2" severity failure;
+    assert g_fft.nof_points=2**true_log2(g_fft.nof_points) report "fft_r2: nof_points must be a power of 2" severity failure;
     -- wb_factor
-    assert g_fft.wb_factor=2**ceil_log2(g_fft.wb_factor) report "fft_r2: wb_factor must be a power of 2" severity failure;
+    assert g_fft.wb_factor=2**true_log2(g_fft.wb_factor) report "fft_r2: wb_factor must be a power of 2" severity failure;
     -- nof_chan
     if g_fft.nof_chan>0 then
       assert g_fft.wb_factor=1 report "fft_r2: nof_chan > 0 is only supported for wb_factor = 1" severity failure;