Move width calculation function to separate package

vunit/builtins.py

@@ -237,6 +237,7 @@ def add_vhdl_builtins(self, external=None):
             "dictionary",
             "run",
             "path",
+            "helpers",
         ):
             self._add_files(VHDL_PATH / path / "src" / "*.vhd")
 

vunit/vhdl/helpers/src/helpers_pkg.vhd

@@ -0,0 +1,22 @@
+-- This Source Code Form is subject to the terms of the Mozilla Public
+-- License, v. 2.0. If a copy of the MPL was not distributed with this file,
+-- You can obtain one at http://mozilla.org/MPL/2.0/.
+--
+-- Copyright (c) 2014-2020, Lars Asplund lars.anders.asplund@gmail.com
+
+package helpers_pkg is
+    function calc_width(d : positive) return natural;
+end package;
+
+package body helpers_pkg is
+    function calc_width(d : positive) return natural is
+      variable i : natural;
+      variable v : natural := d-1;
+    begin
+      while v > 0 loop
+        v := v/2;
+        i := i + 1;
+      end loop;
+      return i;
+    end;
+end package body;

vunit/vhdl/verification_components/src/avalon_stream_pkg.vhd

@@ -10,6 +10,7 @@ use ieee.std_logic_1164.all;
 use work.logger_pkg.all;
 use work.stream_master_pkg.all;
 use work.stream_slave_pkg.all;
+use work.helpers_pkg.all;
 context work.com_context;
 context work.data_types_context;
 
@@ -45,7 +46,6 @@ package avalon_stream_pkg is
                                        channel_length : natural := 0) return avalon_sink_t;
   impure function data_length(source : avalon_source_t) return natural;
   impure function data_length(source : avalon_sink_t) return natural;
-  function calc_empty_length(data_width : positive) return natural;
   impure function empty_length(source : avalon_source_t) return natural;
   impure function empty_length(source : avalon_sink_t) return natural;
   impure function channel_length(source : avalon_source_t) return natural;
@@ -147,27 +147,16 @@ package body avalon_stream_pkg is
     return source.p_data_length;
   end;
 
-  function calc_empty_length(data_width : positive) return natural is
-    variable v : natural;
-    variable i : natural;
-  begin
-    assert data_width mod 8 = 0;
-    v := data_width/8-1;
-    while v > 0 loop
-      v := v/2;
-      i := i + 1;
-    end loop;
-    return i;
-  end;
-
   impure function empty_length(source : avalon_source_t) return natural is
   begin
-    return calc_empty_length(source.p_data_length);
+    assert source.p_data_length mod 8 = 0;
+    return calc_width(source.p_data_length/8);
   end;
 
   impure function empty_length(source : avalon_sink_t) return natural is
   begin
-    return calc_empty_length(source.p_data_length);
+    assert source.p_data_length mod 8 = 0;
+    return calc_width(source.p_data_length/8);
   end;
 
   impure function channel_length(source : avalon_source_t) return natural is

vunit/vhdl/verification_components/test/tb_avalon_stream_pkg.vhd

@@ -15,6 +15,7 @@ context work.data_types_context;
 use work.avalon_stream_pkg.all;
 use work.stream_master_pkg.all;
 use work.stream_slave_pkg.all;
+use work.helpers_pkg.all;
 
 entity tb_avalon_stream_pkg is
   generic (runner_cfg : string);
@@ -78,12 +79,12 @@ begin
       end loop;
 
     elsif run("calculate empty length") then
-      check_equal(calc_empty_length(8), 0);
-      check_equal(calc_empty_length(16), 1);
-      check_equal(calc_empty_length(24), 2);
-      check_equal(calc_empty_length(32), 2);
-      check_equal(calc_empty_length(40), 3);
-      check_equal(calc_empty_length(256), 5);
+      check_equal(calc_width(8/8), 0);
+      check_equal(calc_width(16/8), 1);
+      check_equal(calc_width(24/8), 2);
+      check_equal(calc_width(32/8), 2);
+      check_equal(calc_width(40/8), 3);
+      check_equal(calc_width(256/8), 5);
     end if;
     wait until rising_edge(clk);
     test_runner_cleanup(runner);