diff --git a/README.md b/README.md
index 9ec6049..890f82f 100644
--- a/README.md
+++ b/README.md
@@ -6,19 +6,24 @@ A LGPLv3 licensed library of reusable components for VHDL designs and testbenche
 (Non) synthesible components for testbenches
 
 ##### AssertP
-Package with various assertion procedures
+Package with various assertion procedures.
 
-* `assert_true(x[, str])` checks if boolean x = false, prints string str to console str when given
-* `assert_false(x[, str])` checks if boolean x = false, prints string str to console str when given
-* `assert_equal(x, y[, str])` checks if x = y, prints string str to console str when given
-* `assert_unequal(x, y[, str])` checks if x /= y, prints string str to console str when given
+* `assert_true(x[, str, level])` checks if boolean x = false
+* `assert_false(x[, str, level])` checks if boolean x = false
+* `assert_equal(x, y[, str, level])` checks if x = y
+* `assert_unequal(x, y[, str, level])` checks if x /= y
+
+All of the assert_* procedures have following optional parameters:
+
+* `str` print string str to console instead implemented one
+* `level` severity level (note, warning, error, failure)
 
 ##### SimP
 Package with various components general useful for simulation
 
 * `wait_cycles(x, n)` waits for n rising edges on std_logic signal x
-* `spi_master()` configurable master for SPI protocol
-* `spi_slave()` configurable slave for SPI protocol
+* `spi_master()` configurable master for SPI protocol, supports all cpol/cpha modes
+* `spi_slave()` configurable slave for SPI protocol, supports all cpol/cpha modes
 
 ##### StringP
 Package with various functions to convert to string
diff --git a/sim/AssertP.vhd b/sim/AssertP.vhd
index a3f93d5..3cad3fc 100644
--- a/sim/AssertP.vhd
+++ b/sim/AssertP.vhd
@@ -9,25 +9,39 @@ library libvhdl;
 package AssertP is
 
 
-  procedure assert_true (a : in boolean);
-  procedure assert_true (a : in boolean; str : in string);
+  procedure assert_true (    a : in boolean;
+                           str : in string := "a should be evaluate to true";
+                         level : in severity_level := failure);
 
-  procedure assert_false (a : in boolean);
-  procedure assert_false (a : in boolean; str : in string);
+  procedure assert_false (    a : in boolean;
+                            str : in string := "a should be evaluate to false";
+                          level : in severity_level := failure);
 
-  procedure assert_equal (a : in integer; b : in integer);
-  procedure assert_equal (a : in integer; b : in integer; str : in string);
-  procedure assert_equal (a : in std_logic_vector; b : in std_logic_vector);
-  procedure assert_equal (a : in std_logic_vector; b : in std_logic_vector; str : in string);
-  procedure assert_equal (a : in string; b : in string);
-  procedure assert_equal (a : in string; b : in string; str : in string);
+  procedure assert_equal (a, b  : in integer;
+                          str   : in string := "";
+                          level : in severity_level := failure);
 
-  procedure assert_unequal (a : in integer; b : in integer);
-  procedure assert_unequal (a : in integer; b : in integer; str : in string);
-  procedure assert_unequal (a : in std_logic_vector; b : in std_logic_vector);
-  procedure assert_unequal (a : in std_logic_vector; b : in std_logic_vector; str : in string);
-  procedure assert_unequal (a : in string; b : in string);
-  procedure assert_unequal (a : in string; b : in string; str : in string);
+  procedure assert_equal ( a, b : in std_logic_vector;
+                            str : in string := "";
+                          level : in severity_level := failure);
+
+
+  procedure assert_equal ( a, b : in string;
+                            str : in string := "";
+                          level : in severity_level := failure);
+
+  procedure assert_unequal (a, b  : in integer;
+                            str   : in string := "";
+                            level : in severity_level := failure);
+
+  procedure assert_unequal ( a, b : in std_logic_vector;
+                              str : in string := "";
+                            level : in severity_level := failure);
+
+
+  procedure assert_unequal ( a, b : in string;
+                              str : in string := "";
+                            level : in severity_level := failure);
 
 
 end package AssertP;
@@ -37,116 +51,119 @@ end package AssertP;
 package body AssertP is
 
 
-  procedure assert_true (a : in boolean) is
+  procedure assert_true (    a : in boolean;
+                           str : in string := "a should be evaluate to true";
+                         level : in severity_level := failure) is
   begin
     assert a
-      report "FAILURE: a should be evaluate to true"
-      severity failure;
+      report str
+      severity level;
   end procedure assert_true;
 
-  procedure assert_true (a : in boolean; str : in string) is
-  begin
-    assert a
-      report "FAILURE: " & str
-      severity failure;
-  end procedure assert_true;
 
-  procedure assert_false (a : in boolean) is
+  procedure assert_false (   a : in boolean;
+                           str : in string := "a should be evaluate to false";
+                         level : in severity_level := failure) is
   begin
     assert not(a)
-      report "FAILURE: a should be evaluate to false"
-      severity failure;
+      report str
+      severity level;
   end procedure assert_false;
 
-  procedure assert_false (a : in boolean; str : in string) is
-  begin
-    assert not(a)
-      report "FAILURE: " & str
-      severity failure;
-  end procedure assert_false;
 
-  procedure assert_equal (a : in integer; b : in integer) is
+  procedure assert_equal ( a, b : in integer;
+                            str : in string := "";
+                          level : in severity_level := failure) is
   begin
-    assert a = b
-      report "FAILURE: " & integer'image(a) & " should be equal to " & integer'image(b)
-      severity failure;
+    if (str'length = 0) then
+      assert a = b
+        report integer'image(a) & " should be equal to " & integer'image(b)
+        severity level;
+    else
+      assert a = b
+        report str
+        severity level;
+    end if;
   end procedure assert_equal;
 
-  procedure assert_equal (a : in integer; b : in integer; str : in string) is
-  begin
-    assert a = b
-      report "FAILURE: " & str
-      severity failure;
-  end procedure assert_equal;
-
-  procedure assert_equal (a : in std_logic_vector; b : in std_logic_vector) is
-  begin
-    assert a = b
-      report "FAILURE: " & to_string(a) & " should be equal to " & to_string(b)
-      severity failure;
-  end procedure assert_equal;
 
-  procedure assert_equal (a : in std_logic_vector; b : in std_logic_vector; str : in string) is
+  procedure assert_equal ( a, b : in std_logic_vector;
+                            str : in string := "";
+                          level : in severity_level := failure) is
   begin
-    assert a = b
-      report "FAILURE: " & str
-      severity failure;
+    if (str'length = 0) then
+      assert a = b
+        report "FAILURE: " & to_string(a) & " should be equal to " & to_string(b)
+        severity level;
+    else
+      assert a = b
+        report str
+        severity level;
+    end if;
   end procedure assert_equal;
 
-  procedure assert_equal (a : in string; b : in string) is
-  begin
-    assert a = b
-      report "FAILURE: " & a & " should be equal to " & b
-      severity failure;
-  end procedure assert_equal;
 
-  procedure assert_equal (a : in string; b : in string; str : in string) is
+  procedure assert_equal (  a,b : in string;
+                            str : in string := "";
+                          level : in severity_level := failure) is
   begin
-    assert a = b
-      report "FAILURE: " & str
-      severity failure;
+    if (str'length = 0) then
+      assert a = b
+        report "FAILURE: " & a & " should be equal to " & b
+        severity level;
+    else
+      assert a = b
+        report str
+        severity level;
+    end if;
   end procedure assert_equal;
 
-  procedure assert_unequal (a : in integer; b : in integer) is
-  begin
-    assert a /= b
-      report "FAILURE: " & integer'image(a) & " should be unequal to " & integer'image(b)
-      severity failure;
-  end procedure assert_unequal;
 
-  procedure assert_unequal (a : in integer; b : in integer; str : in string) is
+  procedure assert_unequal ( a, b : in integer;
+                              str : in string := "";
+                            level : in severity_level := failure) is
   begin
-    assert a /= b
-      report "FAILURE: " & str
-      severity failure;
+    if (str'length = 0) then
+      assert a /= b
+        report integer'image(a) & " should not be equal to " & integer'image(b)
+        severity level;
+    else
+      assert a /= b
+        report str
+        severity level;
+    end if;
   end procedure assert_unequal;
 
-  procedure assert_unequal (a : in std_logic_vector; b : in std_logic_vector) is
-  begin
-    assert a /= b
-      report "FAILURE: " & to_string(a) & " should be unequal to " & to_string(b)
-      severity failure;
-  end procedure assert_unequal;
 
-  procedure assert_unequal (a : in std_logic_vector; b : in std_logic_vector; str : in string) is
+  procedure assert_unequal ( a, b : in std_logic_vector;
+                              str : in string := "";
+                            level : in severity_level := failure) is
   begin
-    assert a /= b
-      report "FAILURE: " & str
-      severity failure;
+    if (str'length = 0) then
+      assert a /= b
+        report "FAILURE: " & to_string(a) & " should not be equal to " & to_string(b)
+        severity level;
+    else
+      assert a /= b
+        report str
+        severity level;
+    end if;
   end procedure assert_unequal;
 
-  procedure assert_unequal (a : in string; b : in string) is
-   begin
-    assert a /= b
-      report "FAILURE: " & a & " should be unequal to " & b
-      severity failure;
-  end procedure assert_unequal;
 
-  procedure assert_unequal (a : in string; b : in string; str : in string) is
-   begin
-    assert a /= b
-      report "FAILURE: " & str
-      severity failure;
+  procedure assert_unequal (  a,b : in string;
+                              str : in string := "";
+                            level : in severity_level := failure) is
+  begin
+    if (str'length = 0) then
+      assert a /= b
+        report "FAILURE: " & a & " should not be equal to " & b
+        severity level;
+    else
+      assert a /= b
+        report str
+        severity level;
+    end if;
   end procedure assert_unequal;