vhdl 2008: handle sized bit strings.

10 files changed, 878 insertions, 397 deletions

diff --git a/src/ghdldrv/ghdlprint.adb b/src/ghdldrv/ghdlprint.adb
index 1ab1cad4c..d4e0f5f8a 100644
--- a/src/ghdldrv/ghdlprint.adb
+++ b/src/ghdldrv/ghdlprint.adb
@@ -434,6 +434,7 @@ package body Ghdlprint is
               | Tok_Comma .. Tok_Dot
               | Tok_Equal_Equal
               | Tok_Integer
+              | Tok_Integer_Letter
               | Tok_Real
               | Tok_Equal .. Tok_Slash
               | Tok_Invalid =>
diff --git a/src/vhdl/iirs.adb b/src/vhdl/iirs.adb
index 1462bb371..6864213b6 100644
--- a/src/vhdl/iirs.adb
+++ b/src/vhdl/iirs.adb
@@ -903,16 +903,58 @@ package body Iirs is
    begin
       pragma Assert (Lit /= Null_Iir);
       pragma Assert (Has_Bit_String_Base (Get_Kind (Lit)));
-      return Base_Type'Val (Get_State2 (Lit));
+      return Base_Type'Val (Get_Odigit1 (Lit));
    end Get_Bit_String_Base;
 
    procedure Set_Bit_String_Base (Lit : Iir; Base : Base_Type) is
    begin
       pragma Assert (Lit /= Null_Iir);
       pragma Assert (Has_Bit_String_Base (Get_Kind (Lit)));
-      Set_State2 (Lit, Base_Type'Pos (Base));
+      Set_Odigit1 (Lit, Base_Type'Pos (Base));
    end Set_Bit_String_Base;
 
+   function Get_Has_Signed (Lit : Iir) return Boolean is
+   begin
+      pragma Assert (Lit /= Null_Iir);
+      pragma Assert (Has_Has_Signed (Get_Kind (Lit)));
+      return Get_Flag1 (Lit);
+   end Get_Has_Signed;
+
+   procedure Set_Has_Signed (Lit : Iir; Flag : Boolean) is
+   begin
+      pragma Assert (Lit /= Null_Iir);
+      pragma Assert (Has_Has_Signed (Get_Kind (Lit)));
+      Set_Flag1 (Lit, Flag);
+   end Set_Has_Signed;
+
+   function Get_Has_Sign (Lit : Iir) return Boolean is
+   begin
+      pragma Assert (Lit /= Null_Iir);
+      pragma Assert (Has_Has_Sign (Get_Kind (Lit)));
+      return Get_Flag2 (Lit);
+   end Get_Has_Sign;
+
+   procedure Set_Has_Sign (Lit : Iir; Flag : Boolean) is
+   begin
+      pragma Assert (Lit /= Null_Iir);
+      pragma Assert (Has_Has_Sign (Get_Kind (Lit)));
+      Set_Flag2 (Lit, Flag);
+   end Set_Has_Sign;
+
+   function Get_Has_Length (Lit : Iir) return Boolean is
+   begin
+      pragma Assert (Lit /= Null_Iir);
+      pragma Assert (Has_Has_Length (Get_Kind (Lit)));
+      return Get_Flag3 (Lit);
+   end Get_Has_Length;
+
+   procedure Set_Has_Length (Lit : Iir; Flag : Boolean) is
+   begin
+      pragma Assert (Lit /= Null_Iir);
+      pragma Assert (Has_Has_Length (Get_Kind (Lit)));
+      Set_Flag3 (Lit, Flag);
+   end Set_Has_Length;
+
    function Get_Literal_Origin (Lit : Iir) return Iir is
    begin
       pragma Assert (Lit /= Null_Iir);
diff --git a/src/vhdl/iirs.ads b/src/vhdl/iirs.ads
index 6d3c45ae8..0387f2783 100644
--- a/src/vhdl/iirs.ads
+++ b/src/vhdl/iirs.ads
@@ -284,9 +284,21 @@ package Iirs is
    --
    --   Get/Set_String8_Id (Field5)
    --
-   --   Get/Set_Bit_String_Base (State2)
+   --  Base of the bit_string (corresponds to letters 'b', 'o', 'd' or 'x' in
+   --  the base specifier).
+   --   Get/Set_Bit_String_Base (Odigit1)
    --
    --   Get/Set_Expr_Staticness (State1)
+   --
+   --  True if the bit string is signed, (ie letter 's' is present in the base
+   --  specifier).
+   --   Get/Set_Has_Signed (Flag1)
+   --
+   --  True if the letter 'u' is present in the base specifier.
+   --   Get/Set_Has_Sign (Flag2)
+   --
+   --  True if the integer specifying the length is present.
+   --   Get/Set_Has_Length (Flag3)
 
    -- Iir_Kind_Integer_Literal (Int)
    --
@@ -4579,7 +4591,7 @@ package Iirs is
    --  Purity depth of an impure subprogram.
    Iir_Depth_Impure : constant Iir_Int32 := -1;
 
-   type Base_Type is (Base_None, Base_2, Base_8, Base_16);
+   type Base_Type is (Base_None, Base_2, Base_8, Base_10, Base_16);
 
    -- design file
    subtype Iir_Design_File is Iir;
@@ -5028,11 +5040,36 @@ package Iirs is
    function Get_Simple_Aggregate_List (Target : Iir) return Iir_List;
    procedure Set_Simple_Aggregate_List (Target : Iir; List : Iir_List);
 
-   --  Base of a bit string.
-   --  Field: State2 (pos)
+   --  For a string literal: the string identifier.
+   --  Field: Field5 (uc)
+   function Get_String8_Id (Lit : Iir) return String8_Id;
+   procedure Set_String8_Id (Lit : Iir; Id : String8_Id);
+
+   --  For a string literal: the string length.
+   --  Field: Field4 (uc)
+   function Get_String_Length (Lit : Iir) return Int32;
+   procedure Set_String_Length (Lit : Iir; Len : Int32);
+
+   --  Base of a bit string.  Base_None for a string literal.
+   --  Field: Odigit1 (pos)
    function Get_Bit_String_Base (Lit : Iir) return Base_Type;
    procedure Set_Bit_String_Base (Lit : Iir; Base : Base_Type);
 
+   --  Bit string is signed.
+   --  Field: Flag1
+   function Get_Has_Signed (Lit : Iir) return Boolean;
+   procedure Set_Has_Signed (Lit : Iir; Flag : Boolean);
+
+   --  Bit string sign is explicit
+   --  Field: Flag2
+   function Get_Has_Sign (Lit : Iir) return Boolean;
+   procedure Set_Has_Sign (Lit : Iir; Flag : Boolean);
+
+   --  Bit string length is explicit
+   --  Field: Flag3
+   function Get_Has_Length (Lit : Iir) return Boolean;
+   procedure Set_Has_Length (Lit : Iir; Flag : Boolean);
+
    --  The origin of a literal can be null_iir for a literal generated by the
    --  parser, or a node which was statically evaluated to this literal.
    --  Such nodes are created by eval_expr.
@@ -6232,16 +6269,6 @@ package Iirs is
    function Get_End_Location (Target : Iir) return Location_Type;
    procedure Set_End_Location (Target : Iir; Loc : Location_Type);
 
-   --  For a string literal: the string identifier.
-   --  Field: Field5 (uc)
-   function Get_String8_Id (Lit : Iir) return String8_Id;
-   procedure Set_String8_Id (Lit : Iir; Id : String8_Id);
-
-   --  For a string literal: the string length.
-   --  Field: Field4 (uc)
-   function Get_String_Length (Lit : Iir) return Int32;
-   procedure Set_String_Length (Lit : Iir; Len : Int32);
-
    --  For a declaration: true if the declaration is used somewhere.
    --  Field: Flag6
    function Get_Use_Flag (Decl : Iir) return Boolean;
diff --git a/src/vhdl/nodes_meta.adb b/src/vhdl/nodes_meta.adb
index 9890310f8..62a893563 100644
--- a/src/vhdl/nodes_meta.adb
+++ b/src/vhdl/nodes_meta.adb
@@ -49,6 +49,9 @@ package body Nodes_Meta is
       Field_Fp_Value => Type_Iir_Fp64,
       Field_Simple_Aggregate_List => Type_Iir_List,
       Field_Bit_String_Base => Type_Base_Type,
+      Field_Has_Signed => Type_Boolean,
+      Field_Has_Sign => Type_Boolean,
+      Field_Has_Length => Type_Boolean,
       Field_Literal_Origin => Type_Iir,
       Field_Range_Origin => Type_Iir,
       Field_Literal_Subtype => Type_Iir,
@@ -373,6 +376,12 @@ package body Nodes_Meta is
             return "simple_aggregate_list";
          when Field_Bit_String_Base =>
             return "bit_string_base";
+         when Field_Has_Signed =>
+            return "has_signed";
+         when Field_Has_Sign =>
+            return "has_sign";
+         when Field_Has_Length =>
+            return "has_length";
          when Field_Literal_Origin =>
             return "literal_origin";
          when Field_Range_Origin =>
@@ -1427,6 +1436,12 @@ package body Nodes_Meta is
             return Attr_None;
          when Field_Bit_String_Base =>
             return Attr_None;
+         when Field_Has_Signed =>
+            return Attr_None;
+         when Field_Has_Sign =>
+            return Attr_None;
+         when Field_Has_Length =>
+            return Attr_None;
          when Field_Literal_Origin =>
             return Attr_None;
          when Field_Range_Origin =>
@@ -2004,8 +2019,11 @@ package body Nodes_Meta is
       --  Iir_Kind_String_Literal8
       Field_String_Length,
       Field_String8_Id,
-      Field_Expr_Staticness,
+      Field_Has_Signed,
+      Field_Has_Sign,
+      Field_Has_Length,
       Field_Bit_String_Base,
+      Field_Expr_Staticness,
       Field_Literal_Origin,
       Field_Literal_Subtype,
       Field_Type,
@@ -3789,234 +3807,234 @@ package body Nodes_Meta is
       Iir_Kind_Integer_Literal => 45,
       Iir_Kind_Floating_Point_Literal => 49,
       Iir_Kind_Null_Literal => 51,
-      Iir_Kind_String_Literal8 => 58,
-      Iir_Kind_Physical_Int_Literal => 63,
-      Iir_Kind_Physical_Fp_Literal => 68,
-      Iir_Kind_Simple_Aggregate => 73,
-      Iir_Kind_Overflow_Literal => 76,
-      Iir_Kind_Waveform_Element => 79,
-      Iir_Kind_Conditional_Waveform => 82,
-      Iir_Kind_Association_Element_By_Expression => 89,
-      Iir_Kind_Association_Element_By_Individual => 95,
-      Iir_Kind_Association_Element_Open => 100,
-      Iir_Kind_Association_Element_Package => 106,
-      Iir_Kind_Choice_By_Others => 111,
-      Iir_Kind_Choice_By_Expression => 118,
-      Iir_Kind_Choice_By_Range => 125,
-      Iir_Kind_Choice_By_None => 130,
-      Iir_Kind_Choice_By_Name => 136,
-      Iir_Kind_Entity_Aspect_Entity => 138,
-      Iir_Kind_Entity_Aspect_Configuration => 139,
-      Iir_Kind_Entity_Aspect_Open => 139,
-      Iir_Kind_Block_Configuration => 145,
-      Iir_Kind_Block_Header => 149,
-      Iir_Kind_Component_Configuration => 155,
-      Iir_Kind_Binding_Indication => 161,
-      Iir_Kind_Entity_Class => 163,
-      Iir_Kind_Attribute_Value => 171,
-      Iir_Kind_Signature => 174,
-      Iir_Kind_Aggregate_Info => 181,
-      Iir_Kind_Procedure_Call => 185,
-      Iir_Kind_Record_Element_Constraint => 191,
-      Iir_Kind_Array_Element_Resolution => 192,
-      Iir_Kind_Record_Resolution => 193,
-      Iir_Kind_Record_Element_Resolution => 196,
-      Iir_Kind_Attribute_Specification => 204,
-      Iir_Kind_Disconnection_Specification => 209,
-      Iir_Kind_Configuration_Specification => 214,
-      Iir_Kind_Access_Type_Definition => 221,
-      Iir_Kind_Incomplete_Type_Definition => 228,
-      Iir_Kind_File_Type_Definition => 235,
-      Iir_Kind_Protected_Type_Declaration => 244,
-      Iir_Kind_Record_Type_Definition => 254,
-      Iir_Kind_Array_Type_Definition => 266,
-      Iir_Kind_Array_Subtype_Definition => 281,
-      Iir_Kind_Record_Subtype_Definition => 292,
-      Iir_Kind_Access_Subtype_Definition => 300,
-      Iir_Kind_Physical_Subtype_Definition => 309,
-      Iir_Kind_Floating_Subtype_Definition => 319,
-      Iir_Kind_Integer_Subtype_Definition => 328,
-      Iir_Kind_Enumeration_Subtype_Definition => 337,
-      Iir_Kind_Enumeration_Type_Definition => 346,
-      Iir_Kind_Integer_Type_Definition => 352,
-      Iir_Kind_Floating_Type_Definition => 358,
-      Iir_Kind_Physical_Type_Definition => 367,
-      Iir_Kind_Range_Expression => 373,
-      Iir_Kind_Protected_Type_Body => 380,
-      Iir_Kind_Subtype_Definition => 384,
-      Iir_Kind_Scalar_Nature_Definition => 388,
-      Iir_Kind_Overload_List => 389,
-      Iir_Kind_Type_Declaration => 395,
-      Iir_Kind_Anonymous_Type_Declaration => 400,
-      Iir_Kind_Subtype_Declaration => 408,
-      Iir_Kind_Nature_Declaration => 414,
-      Iir_Kind_Subnature_Declaration => 420,
-      Iir_Kind_Package_Declaration => 430,
-      Iir_Kind_Package_Instantiation_Declaration => 441,
-      Iir_Kind_Package_Body => 448,
-      Iir_Kind_Configuration_Declaration => 457,
-      Iir_Kind_Entity_Declaration => 469,
-      Iir_Kind_Architecture_Body => 481,
-      Iir_Kind_Package_Header => 483,
-      Iir_Kind_Unit_Declaration => 492,
-      Iir_Kind_Library_Declaration => 499,
-      Iir_Kind_Component_Declaration => 509,
-      Iir_Kind_Attribute_Declaration => 516,
-      Iir_Kind_Group_Template_Declaration => 522,
-      Iir_Kind_Group_Declaration => 529,
-      Iir_Kind_Element_Declaration => 536,
-      Iir_Kind_Non_Object_Alias_Declaration => 544,
-      Iir_Kind_Psl_Declaration => 552,
-      Iir_Kind_Terminal_Declaration => 558,
-      Iir_Kind_Free_Quantity_Declaration => 567,
-      Iir_Kind_Across_Quantity_Declaration => 579,
-      Iir_Kind_Through_Quantity_Declaration => 591,
-      Iir_Kind_Enumeration_Literal => 602,
-      Iir_Kind_Function_Declaration => 626,
-      Iir_Kind_Procedure_Declaration => 648,
-      Iir_Kind_Function_Body => 658,
-      Iir_Kind_Procedure_Body => 668,
-      Iir_Kind_Object_Alias_Declaration => 680,
-      Iir_Kind_File_Declaration => 695,
-      Iir_Kind_Guard_Signal_Declaration => 708,
-      Iir_Kind_Signal_Declaration => 725,
-      Iir_Kind_Variable_Declaration => 738,
-      Iir_Kind_Constant_Declaration => 752,
-      Iir_Kind_Iterator_Declaration => 764,
-      Iir_Kind_Interface_Constant_Declaration => 780,
-      Iir_Kind_Interface_Variable_Declaration => 796,
-      Iir_Kind_Interface_Signal_Declaration => 817,
-      Iir_Kind_Interface_File_Declaration => 833,
-      Iir_Kind_Interface_Package_Declaration => 842,
-      Iir_Kind_Identity_Operator => 846,
-      Iir_Kind_Negation_Operator => 850,
-      Iir_Kind_Absolute_Operator => 854,
-      Iir_Kind_Not_Operator => 858,
-      Iir_Kind_Condition_Operator => 862,
-      Iir_Kind_Reduction_And_Operator => 866,
-      Iir_Kind_Reduction_Or_Operator => 870,
-      Iir_Kind_Reduction_Nand_Operator => 874,
-      Iir_Kind_Reduction_Nor_Operator => 878,
-      Iir_Kind_Reduction_Xor_Operator => 882,
-      Iir_Kind_Reduction_Xnor_Operator => 886,
-      Iir_Kind_And_Operator => 891,
-      Iir_Kind_Or_Operator => 896,
-      Iir_Kind_Nand_Operator => 901,
-      Iir_Kind_Nor_Operator => 906,
-      Iir_Kind_Xor_Operator => 911,
-      Iir_Kind_Xnor_Operator => 916,
-      Iir_Kind_Equality_Operator => 921,
-      Iir_Kind_Inequality_Operator => 926,
-      Iir_Kind_Less_Than_Operator => 931,
-      Iir_Kind_Less_Than_Or_Equal_Operator => 936,
-      Iir_Kind_Greater_Than_Operator => 941,
-      Iir_Kind_Greater_Than_Or_Equal_Operator => 946,
-      Iir_Kind_Match_Equality_Operator => 951,
-      Iir_Kind_Match_Inequality_Operator => 956,
-      Iir_Kind_Match_Less_Than_Operator => 961,
-      Iir_Kind_Match_Less_Than_Or_Equal_Operator => 966,
-      Iir_Kind_Match_Greater_Than_Operator => 971,
-      Iir_Kind_Match_Greater_Than_Or_Equal_Operator => 976,
-      Iir_Kind_Sll_Operator => 981,
-      Iir_Kind_Sla_Operator => 986,
-      Iir_Kind_Srl_Operator => 991,
-      Iir_Kind_Sra_Operator => 996,
-      Iir_Kind_Rol_Operator => 1001,
-      Iir_Kind_Ror_Operator => 1006,
-      Iir_Kind_Addition_Operator => 1011,
-      Iir_Kind_Substraction_Operator => 1016,
-      Iir_Kind_Concatenation_Operator => 1021,
-      Iir_Kind_Multiplication_Operator => 1026,
-      Iir_Kind_Division_Operator => 1031,
-      Iir_Kind_Modulus_Operator => 1036,
-      Iir_Kind_Remainder_Operator => 1041,
-      Iir_Kind_Exponentiation_Operator => 1046,
-      Iir_Kind_Function_Call => 1054,
-      Iir_Kind_Aggregate => 1060,
-      Iir_Kind_Parenthesis_Expression => 1063,
-      Iir_Kind_Qualified_Expression => 1067,
-      Iir_Kind_Type_Conversion => 1072,
-      Iir_Kind_Allocator_By_Expression => 1076,
-      Iir_Kind_Allocator_By_Subtype => 1080,
-      Iir_Kind_Selected_Element => 1086,
-      Iir_Kind_Dereference => 1091,
-      Iir_Kind_Implicit_Dereference => 1096,
-      Iir_Kind_Slice_Name => 1103,
-      Iir_Kind_Indexed_Name => 1109,
-      Iir_Kind_Psl_Expression => 1111,
-      Iir_Kind_Sensitized_Process_Statement => 1130,
-      Iir_Kind_Process_Statement => 1148,
-      Iir_Kind_Concurrent_Conditional_Signal_Assignment => 1159,
-      Iir_Kind_Concurrent_Selected_Signal_Assignment => 1171,
-      Iir_Kind_Concurrent_Assertion_Statement => 1179,
-      Iir_Kind_Psl_Default_Clock => 1183,
-      Iir_Kind_Psl_Assert_Statement => 1192,
-      Iir_Kind_Psl_Cover_Statement => 1201,
-      Iir_Kind_Concurrent_Procedure_Call_Statement => 1207,
-      Iir_Kind_Block_Statement => 1220,
-      Iir_Kind_Generate_Statement => 1232,
-      Iir_Kind_Component_Instantiation_Statement => 1242,
-      Iir_Kind_Simple_Simultaneous_Statement => 1249,
-      Iir_Kind_Signal_Assignment_Statement => 1258,
-      Iir_Kind_Null_Statement => 1262,
-      Iir_Kind_Assertion_Statement => 1269,
-      Iir_Kind_Report_Statement => 1275,
-      Iir_Kind_Wait_Statement => 1282,
-      Iir_Kind_Variable_Assignment_Statement => 1288,
-      Iir_Kind_Return_Statement => 1294,
-      Iir_Kind_For_Loop_Statement => 1302,
-      Iir_Kind_While_Loop_Statement => 1309,
-      Iir_Kind_Next_Statement => 1315,
-      Iir_Kind_Exit_Statement => 1321,
-      Iir_Kind_Case_Statement => 1328,
-      Iir_Kind_Procedure_Call_Statement => 1333,
-      Iir_Kind_If_Statement => 1341,
-      Iir_Kind_Elsif => 1346,
-      Iir_Kind_Character_Literal => 1353,
-      Iir_Kind_Simple_Name => 1360,
-      Iir_Kind_Selected_Name => 1368,
-      Iir_Kind_Operator_Symbol => 1373,
-      Iir_Kind_Selected_By_All_Name => 1378,
-      Iir_Kind_Parenthesis_Name => 1382,
-      Iir_Kind_Base_Attribute => 1384,
-      Iir_Kind_Left_Type_Attribute => 1389,
-      Iir_Kind_Right_Type_Attribute => 1394,
-      Iir_Kind_High_Type_Attribute => 1399,
-      Iir_Kind_Low_Type_Attribute => 1404,
-      Iir_Kind_Ascending_Type_Attribute => 1409,
-      Iir_Kind_Image_Attribute => 1415,
-      Iir_Kind_Value_Attribute => 1421,
-      Iir_Kind_Pos_Attribute => 1427,
-      Iir_Kind_Val_Attribute => 1433,
-      Iir_Kind_Succ_Attribute => 1439,
-      Iir_Kind_Pred_Attribute => 1445,
-      Iir_Kind_Leftof_Attribute => 1451,
-      Iir_Kind_Rightof_Attribute => 1457,
-      Iir_Kind_Delayed_Attribute => 1465,
-      Iir_Kind_Stable_Attribute => 1473,
-      Iir_Kind_Quiet_Attribute => 1481,
-      Iir_Kind_Transaction_Attribute => 1489,
-      Iir_Kind_Event_Attribute => 1493,
-      Iir_Kind_Active_Attribute => 1497,
-      Iir_Kind_Last_Event_Attribute => 1501,
-      Iir_Kind_Last_Active_Attribute => 1505,
-      Iir_Kind_Last_Value_Attribute => 1509,
-      Iir_Kind_Driving_Attribute => 1513,
-      Iir_Kind_Driving_Value_Attribute => 1517,
-      Iir_Kind_Behavior_Attribute => 1517,
-      Iir_Kind_Structure_Attribute => 1517,
-      Iir_Kind_Simple_Name_Attribute => 1524,
-      Iir_Kind_Instance_Name_Attribute => 1529,
-      Iir_Kind_Path_Name_Attribute => 1534,
-      Iir_Kind_Left_Array_Attribute => 1541,
-      Iir_Kind_Right_Array_Attribute => 1548,
-      Iir_Kind_High_Array_Attribute => 1555,
-      Iir_Kind_Low_Array_Attribute => 1562,
-      Iir_Kind_Length_Array_Attribute => 1569,
-      Iir_Kind_Ascending_Array_Attribute => 1576,
-      Iir_Kind_Range_Array_Attribute => 1583,
-      Iir_Kind_Reverse_Range_Array_Attribute => 1590,
-      Iir_Kind_Attribute_Name => 1598
+      Iir_Kind_String_Literal8 => 61,
+      Iir_Kind_Physical_Int_Literal => 66,
+      Iir_Kind_Physical_Fp_Literal => 71,
+      Iir_Kind_Simple_Aggregate => 76,
+      Iir_Kind_Overflow_Literal => 79,
+      Iir_Kind_Waveform_Element => 82,
+      Iir_Kind_Conditional_Waveform => 85,
+      Iir_Kind_Association_Element_By_Expression => 92,
+      Iir_Kind_Association_Element_By_Individual => 98,
+      Iir_Kind_Association_Element_Open => 103,
+      Iir_Kind_Association_Element_Package => 109,
+      Iir_Kind_Choice_By_Others => 114,
+      Iir_Kind_Choice_By_Expression => 121,
+      Iir_Kind_Choice_By_Range => 128,
+      Iir_Kind_Choice_By_None => 133,
+      Iir_Kind_Choice_By_Name => 139,
+      Iir_Kind_Entity_Aspect_Entity => 141,
+      Iir_Kind_Entity_Aspect_Configuration => 142,
+      Iir_Kind_Entity_Aspect_Open => 142,
+      Iir_Kind_Block_Configuration => 148,
+      Iir_Kind_Block_Header => 152,
+      Iir_Kind_Component_Configuration => 158,
+      Iir_Kind_Binding_Indication => 164,
+      Iir_Kind_Entity_Class => 166,
+      Iir_Kind_Attribute_Value => 174,
+      Iir_Kind_Signature => 177,
+      Iir_Kind_Aggregate_Info => 184,
+      Iir_Kind_Procedure_Call => 188,
+      Iir_Kind_Record_Element_Constraint => 194,
+      Iir_Kind_Array_Element_Resolution => 195,
+      Iir_Kind_Record_Resolution => 196,
+      Iir_Kind_Record_Element_Resolution => 199,
+      Iir_Kind_Attribute_Specification => 207,
+      Iir_Kind_Disconnection_Specification => 212,
+      Iir_Kind_Configuration_Specification => 217,
+      Iir_Kind_Access_Type_Definition => 224,
+      Iir_Kind_Incomplete_Type_Definition => 231,
+      Iir_Kind_File_Type_Definition => 238,
+      Iir_Kind_Protected_Type_Declaration => 247,
+      Iir_Kind_Record_Type_Definition => 257,
+      Iir_Kind_Array_Type_Definition => 269,
+      Iir_Kind_Array_Subtype_Definition => 284,
+      Iir_Kind_Record_Subtype_Definition => 295,
+      Iir_Kind_Access_Subtype_Definition => 303,
+      Iir_Kind_Physical_Subtype_Definition => 312,
+      Iir_Kind_Floating_Subtype_Definition => 322,
+      Iir_Kind_Integer_Subtype_Definition => 331,
+      Iir_Kind_Enumeration_Subtype_Definition => 340,
+      Iir_Kind_Enumeration_Type_Definition => 349,
+      Iir_Kind_Integer_Type_Definition => 355,
+      Iir_Kind_Floating_Type_Definition => 361,
+      Iir_Kind_Physical_Type_Definition => 370,
+      Iir_Kind_Range_Expression => 376,
+      Iir_Kind_Protected_Type_Body => 383,
+      Iir_Kind_Subtype_Definition => 387,
+      Iir_Kind_Scalar_Nature_Definition => 391,
+      Iir_Kind_Overload_List => 392,
+      Iir_Kind_Type_Declaration => 398,
+      Iir_Kind_Anonymous_Type_Declaration => 403,
+      Iir_Kind_Subtype_Declaration => 411,
+      Iir_Kind_Nature_Declaration => 417,
+      Iir_Kind_Subnature_Declaration => 423,
+      Iir_Kind_Package_Declaration => 433,
+      Iir_Kind_Package_Instantiation_Declaration => 444,
+      Iir_Kind_Package_Body => 451,
+      Iir_Kind_Configuration_Declaration => 460,
+      Iir_Kind_Entity_Declaration => 472,
+      Iir_Kind_Architecture_Body => 484,
+      Iir_Kind_Package_Header => 486,
+      Iir_Kind_Unit_Declaration => 495,
+      Iir_Kind_Library_Declaration => 502,
+      Iir_Kind_Component_Declaration => 512,
+      Iir_Kind_Attribute_Declaration => 519,
+      Iir_Kind_Group_Template_Declaration => 525,
+      Iir_Kind_Group_Declaration => 532,
+      Iir_Kind_Element_Declaration => 539,
+      Iir_Kind_Non_Object_Alias_Declaration => 547,
+      Iir_Kind_Psl_Declaration => 555,
+      Iir_Kind_Terminal_Declaration => 561,
+      Iir_Kind_Free_Quantity_Declaration => 570,
+      Iir_Kind_Across_Quantity_Declaration => 582,
+      Iir_Kind_Through_Quantity_Declaration => 594,
+      Iir_Kind_Enumeration_Literal => 605,
+      Iir_Kind_Function_Declaration => 629,
+      Iir_Kind_Procedure_Declaration => 651,
+      Iir_Kind_Function_Body => 661,
+      Iir_Kind_Procedure_Body => 671,
+      Iir_Kind_Object_Alias_Declaration => 683,
+      Iir_Kind_File_Declaration => 698,
+      Iir_Kind_Guard_Signal_Declaration => 711,
+      Iir_Kind_Signal_Declaration => 728,
+      Iir_Kind_Variable_Declaration => 741,
+      Iir_Kind_Constant_Declaration => 755,
+      Iir_Kind_Iterator_Declaration => 767,
+      Iir_Kind_Interface_Constant_Declaration => 783,
+      Iir_Kind_Interface_Variable_Declaration => 799,
+      Iir_Kind_Interface_Signal_Declaration => 820,
+      Iir_Kind_Interface_File_Declaration => 836,
+      Iir_Kind_Interface_Package_Declaration => 845,
+      Iir_Kind_Identity_Operator => 849,
+      Iir_Kind_Negation_Operator => 853,
+      Iir_Kind_Absolute_Operator => 857,
+      Iir_Kind_Not_Operator => 861,
+      Iir_Kind_Condition_Operator => 865,
+      Iir_Kind_Reduction_And_Operator => 869,
+      Iir_Kind_Reduction_Or_Operator => 873,
+      Iir_Kind_Reduction_Nand_Operator => 877,
+      Iir_Kind_Reduction_Nor_Operator => 881,
+      Iir_Kind_Reduction_Xor_Operator => 885,
+      Iir_Kind_Reduction_Xnor_Operator => 889,
+      Iir_Kind_And_Operator => 894,
+      Iir_Kind_Or_Operator => 899,
+      Iir_Kind_Nand_Operator => 904,
+      Iir_Kind_Nor_Operator => 909,
+      Iir_Kind_Xor_Operator => 914,
+      Iir_Kind_Xnor_Operator => 919,
+      Iir_Kind_Equality_Operator => 924,
+      Iir_Kind_Inequality_Operator => 929,
+      Iir_Kind_Less_Than_Operator => 934,
+      Iir_Kind_Less_Than_Or_Equal_Operator => 939,
+      Iir_Kind_Greater_Than_Operator => 944,
+      Iir_Kind_Greater_Than_Or_Equal_Operator => 949,
+      Iir_Kind_Match_Equality_Operator => 954,
+      Iir_Kind_Match_Inequality_Operator => 959,
+      Iir_Kind_Match_Less_Than_Operator => 964,
+      Iir_Kind_Match_Less_Than_Or_Equal_Operator => 969,
+      Iir_Kind_Match_Greater_Than_Operator => 974,
+      Iir_Kind_Match_Greater_Than_Or_Equal_Operator => 979,
+      Iir_Kind_Sll_Operator => 984,
+      Iir_Kind_Sla_Operator => 989,
+      Iir_Kind_Srl_Operator => 994,
+      Iir_Kind_Sra_Operator => 999,
+      Iir_Kind_Rol_Operator => 1004,
+      Iir_Kind_Ror_Operator => 1009,
+      Iir_Kind_Addition_Operator => 1014,
+      Iir_Kind_Substraction_Operator => 1019,
+      Iir_Kind_Concatenation_Operator => 1024,
+      Iir_Kind_Multiplication_Operator => 1029,
+      Iir_Kind_Division_Operator => 1034,
+      Iir_Kind_Modulus_Operator => 1039,
+      Iir_Kind_Remainder_Operator => 1044,
+      Iir_Kind_Exponentiation_Operator => 1049,
+      Iir_Kind_Function_Call => 1057,
+      Iir_Kind_Aggregate => 1063,
+      Iir_Kind_Parenthesis_Expression => 1066,
+      Iir_Kind_Qualified_Expression => 1070,
+      Iir_Kind_Type_Conversion => 1075,
+      Iir_Kind_Allocator_By_Expression => 1079,
+      Iir_Kind_Allocator_By_Subtype => 1083,
+      Iir_Kind_Selected_Element => 1089,
+      Iir_Kind_Dereference => 1094,
+      Iir_Kind_Implicit_Dereference => 1099,
+      Iir_Kind_Slice_Name => 1106,
+      Iir_Kind_Indexed_Name => 1112,
+      Iir_Kind_Psl_Expression => 1114,
+      Iir_Kind_Sensitized_Process_Statement => 1133,
+      Iir_Kind_Process_Statement => 1151,
+      Iir_Kind_Concurrent_Conditional_Signal_Assignment => 1162,
+      Iir_Kind_Concurrent_Selected_Signal_Assignment => 1174,
+      Iir_Kind_Concurrent_Assertion_Statement => 1182,
+      Iir_Kind_Psl_Default_Clock => 1186,
+      Iir_Kind_Psl_Assert_Statement => 1195,
+      Iir_Kind_Psl_Cover_Statement => 1204,
+      Iir_Kind_Concurrent_Procedure_Call_Statement => 1210,
+      Iir_Kind_Block_Statement => 1223,
+      Iir_Kind_Generate_Statement => 1235,
+      Iir_Kind_Component_Instantiation_Statement => 1245,
+      Iir_Kind_Simple_Simultaneous_Statement => 1252,
+      Iir_Kind_Signal_Assignment_Statement => 1261,
+      Iir_Kind_Null_Statement => 1265,
+      Iir_Kind_Assertion_Statement => 1272,
+      Iir_Kind_Report_Statement => 1278,
+      Iir_Kind_Wait_Statement => 1285,
+      Iir_Kind_Variable_Assignment_Statement => 1291,
+      Iir_Kind_Return_Statement => 1297,
+      Iir_Kind_For_Loop_Statement => 1305,
+      Iir_Kind_While_Loop_Statement => 1312,
+      Iir_Kind_Next_Statement => 1318,
+      Iir_Kind_Exit_Statement => 1324,
+      Iir_Kind_Case_Statement => 1331,
+      Iir_Kind_Procedure_Call_Statement => 1336,
+      Iir_Kind_If_Statement => 1344,
+      Iir_Kind_Elsif => 1349,
+      Iir_Kind_Character_Literal => 1356,
+      Iir_Kind_Simple_Name => 1363,
+      Iir_Kind_Selected_Name => 1371,
+      Iir_Kind_Operator_Symbol => 1376,
+      Iir_Kind_Selected_By_All_Name => 1381,
+      Iir_Kind_Parenthesis_Name => 1385,
+      Iir_Kind_Base_Attribute => 1387,
+      Iir_Kind_Left_Type_Attribute => 1392,
+      Iir_Kind_Right_Type_Attribute => 1397,
+      Iir_Kind_High_Type_Attribute => 1402,
+      Iir_Kind_Low_Type_Attribute => 1407,
+      Iir_Kind_Ascending_Type_Attribute => 1412,
+      Iir_Kind_Image_Attribute => 1418,
+      Iir_Kind_Value_Attribute => 1424,
+      Iir_Kind_Pos_Attribute => 1430,
+      Iir_Kind_Val_Attribute => 1436,
+      Iir_Kind_Succ_Attribute => 1442,
+      Iir_Kind_Pred_Attribute => 1448,
+      Iir_Kind_Leftof_Attribute => 1454,
+      Iir_Kind_Rightof_Attribute => 1460,
+      Iir_Kind_Delayed_Attribute => 1468,
+      Iir_Kind_Stable_Attribute => 1476,
+      Iir_Kind_Quiet_Attribute => 1484,
+      Iir_Kind_Transaction_Attribute => 1492,
+      Iir_Kind_Event_Attribute => 1496,
+      Iir_Kind_Active_Attribute => 1500,
+      Iir_Kind_Last_Event_Attribute => 1504,
+      Iir_Kind_Last_Active_Attribute => 1508,
+      Iir_Kind_Last_Value_Attribute => 1512,
+      Iir_Kind_Driving_Attribute => 1516,
+      Iir_Kind_Driving_Value_Attribute => 1520,
+      Iir_Kind_Behavior_Attribute => 1520,
+      Iir_Kind_Structure_Attribute => 1520,
+      Iir_Kind_Simple_Name_Attribute => 1527,
+      Iir_Kind_Instance_Name_Attribute => 1532,
+      Iir_Kind_Path_Name_Attribute => 1537,
+      Iir_Kind_Left_Array_Attribute => 1544,
+      Iir_Kind_Right_Array_Attribute => 1551,
+      Iir_Kind_High_Array_Attribute => 1558,
+      Iir_Kind_Low_Array_Attribute => 1565,
+      Iir_Kind_Length_Array_Attribute => 1572,
+      Iir_Kind_Ascending_Array_Attribute => 1579,
+      Iir_Kind_Range_Array_Attribute => 1586,
+      Iir_Kind_Reverse_Range_Array_Attribute => 1593,
+      Iir_Kind_Attribute_Name => 1601
      );
 
    function Get_Fields (K : Iir_Kind) return Fields_Array
@@ -4062,6 +4080,12 @@ package body Nodes_Meta is
    begin
       pragma Assert (Fields_Type (F) = Type_Boolean);
       case F is
+         when Field_Has_Signed =>
+            return Get_Has_Signed (N);
+         when Field_Has_Sign =>
+            return Get_Has_Sign (N);
+         when Field_Has_Length =>
+            return Get_Has_Length (N);
          when Field_Whole_Association_Flag =>
             return Get_Whole_Association_Flag (N);
          when Field_Collapse_Signal_Flag =>
@@ -4158,6 +4182,12 @@ package body Nodes_Meta is
    begin
       pragma Assert (Fields_Type (F) = Type_Boolean);
       case F is
+         when Field_Has_Signed =>
+            Set_Has_Signed (N, V);
+         when Field_Has_Sign =>
+            Set_Has_Sign (N, V);
+         when Field_Has_Length =>
+            Set_Has_Length (N, V);
          when Field_Whole_Association_Flag =>
             Set_Whole_Association_Flag (N, V);
          when Field_Collapse_Signal_Flag =>
@@ -5924,6 +5954,21 @@ package body Nodes_Meta is
       return K = Iir_Kind_String_Literal8;
    end Has_Bit_String_Base;
 
+   function Has_Has_Signed (K : Iir_Kind) return Boolean is
+   begin
+      return K = Iir_Kind_String_Literal8;
+   end Has_Has_Signed;
+
+   function Has_Has_Sign (K : Iir_Kind) return Boolean is
+   begin
+      return K = Iir_Kind_String_Literal8;
+   end Has_Has_Sign;
+
+   function Has_Has_Length (K : Iir_Kind) return Boolean is
+   begin
+      return K = Iir_Kind_String_Literal8;
+   end Has_Has_Length;
+
    function Has_Literal_Origin (K : Iir_Kind) return Boolean is
    begin
       case K is
diff --git a/src/vhdl/nodes_meta.ads b/src/vhdl/nodes_meta.ads
index a120a769a..a04a31114 100644
--- a/src/vhdl/nodes_meta.ads
+++ b/src/vhdl/nodes_meta.ads
@@ -88,6 +88,9 @@ package Nodes_Meta is
       Field_Fp_Value,
       Field_Simple_Aggregate_List,
       Field_Bit_String_Base,
+      Field_Has_Signed,
+      Field_Has_Sign,
+      Field_Has_Length,
       Field_Literal_Origin,
       Field_Range_Origin,
       Field_Literal_Subtype,
@@ -548,6 +551,9 @@ package Nodes_Meta is
    function Has_Fp_Value (K : Iir_Kind) return Boolean;
    function Has_Simple_Aggregate_List (K : Iir_Kind) return Boolean;
    function Has_Bit_String_Base (K : Iir_Kind) return Boolean;
+   function Has_Has_Signed (K : Iir_Kind) return Boolean;
+   function Has_Has_Sign (K : Iir_Kind) return Boolean;
+   function Has_Has_Length (K : Iir_Kind) return Boolean;
    function Has_Literal_Origin (K : Iir_Kind) return Boolean;
    function Has_Range_Origin (K : Iir_Kind) return Boolean;
    function Has_Literal_Subtype (K : Iir_Kind) return Boolean;
diff --git a/src/vhdl/parse.adb b/src/vhdl/parse.adb
index dedcee1a7..0633cad67 100644
--- a/src/vhdl/parse.adb
+++ b/src/vhdl/parse.adb
@@ -3943,6 +3943,176 @@ package body Parse is
       return Res;
    end Parse_Allocator;
 
+   --  precond : tok_bit_string
+   --  postcond: tok_bit_string
+   --
+   --  Simply create the node for a bit string.
+   function Parse_Bit_String return Iir
+   is
+      Res : Iir;
+      C : Character;
+      B : Base_Type;
+   begin
+      Res := Create_Iir (Iir_Kind_String_Literal8);
+      Set_Location (Res);
+      Set_String8_Id (Res, Current_String_Id);
+      Set_String_Length (Res, Current_String_Length);
+      if Name_Table.Name_Buffer (1) = 's' then
+         Set_Has_Sign (Res, True);
+         Set_Has_Signed (Res, True);
+         pragma Assert (Name_Table.Name_Length = 2);
+         C := Name_Table.Name_Buffer (2);
+      elsif Name_Table.Name_Buffer (1) = 'u' then
+         Set_Has_Sign (Res, True);
+         Set_Has_Signed (Res, False);
+         pragma Assert (Name_Table.Name_Length = 2);
+         C := Name_Table.Name_Buffer (2);
+      else
+         Set_Has_Sign (Res, False);
+         Set_Has_Signed (Res, False);
+         pragma Assert (Name_Table.Name_Length = 1);
+         C := Name_Table.Name_Buffer (1);
+      end if;
+
+      case C is
+         when 'b' =>
+            B := Base_2;
+         when 'o' =>
+            B := Base_8;
+         when 'd' =>
+            B := Base_10;
+         when 'x' =>
+            B := Base_16;
+         when others =>
+            raise Internal_Error;
+      end case;
+      Set_Bit_String_Base (Res, B);
+
+      return Res;
+   end Parse_Bit_String;
+
+   --  Scan returns an expanded bit value.  Adjust the expanded bit value as
+   --  required by the length.
+   procedure Resize_Bit_String (Lit : Iir; Nlen : Nat32)
+   is
+      use Str_Table;
+
+      Old_Len : constant Nat32 := Get_String_Length (Lit);
+      Is_Signed : constant Boolean := Get_Has_Signed (Lit);
+      Id : constant String8_Id := Get_String8_Id (Lit);
+      C : Nat8;
+   begin
+      if Nlen > Old_Len then
+         --  Extend.
+
+         --  LRM08 15.8
+         --  -- If the length is greater than the number of characters in the
+         --     expanded bit value and the base specifier is B, UB, O, UO, X,
+         --     UX or D, the bit string value is obtained by concatenating a
+         --     string of 0 digits to the left of the expanded bit value.  The
+         --     number of 0 digits in the string is such that the number of
+         --     characters in the result of the concatenation is the length of
+         --     the bit string literal.
+         --
+         --  -- If the length is greater than the number of characters in the
+         --     expanded bit value and the base specifier is SB, SO or SX, the
+         --     bit string value is obtained by concatenating the the left of
+         --     the expanded bit value a string, each of whose characters is
+         --     the leftmost character of the expanded bit value.  The number
+         --     of characters in the string is such that the number of
+         --     characters in the result of the concatenation is the length of
+         --     the bit string literal.
+         if Is_Signed then
+            if Old_Len = 0 then
+               Error_Msg_Parse
+                 ("cannot expand an empty signed bit string", Lit);
+               C := Character'Pos ('0');
+            else
+               C := Element_String8 (Id, 1);
+            end if;
+         else
+            C := Character'Pos ('0');
+         end if;
+         Resize_String8 (Nlen);
+         --  Shift (position 1 is the MSB).
+         for I in reverse 1 .. Old_Len loop
+            Set_Element_String8 (Id, I + Nlen - Old_Len,
+                                 Element_String8 (Id, I));
+         end loop;
+         for I in 1 .. Nlen - Old_Len loop
+            Set_Element_String8 (Id, I, C);
+         end loop;
+         Set_String_Length (Lit, Nlen);
+
+      elsif Nlen < Old_Len then
+         --  Reduce.
+
+         --  LRM08 15.8
+         --  -- If the length is less than the number of characters in the
+         --     expanded bit value and the base specifier is B, UB, O, UO, X,
+         --     UX or D, the bit string value is obtained by deleting
+         --     sufficient characters from the left of the expanded bit value
+         --     to yield a string whose length is the length of the bit string
+         --     literal.  It is an error if any of the character so deleted is
+         --     other than the digit 0.
+         --
+         --  -- If the length is less than the number of characters in the
+         --     expanded bit value and the base specifier is SB, SO or SX, the
+         --     bit string value is obtained by deleting sufficient characters
+         --     from the left of the expanded bit value to yield a string whose
+         --     length is the length of the bit string literal.  It is an error
+         --     if any of the characters so deleted differs from the leftmost
+         --     remaining character.
+         if Is_Signed then
+            C := Element_String8 (Id, 1 + Old_Len - Nlen);
+         else
+            C := Character'Pos ('0');
+         end if;
+         for I in 1 .. Old_Len - Nlen loop
+            if Element_String8 (Id, I) /= C then
+               Error_Msg_Parse
+                 ("truncation of bit string changes the value", Lit);
+               --  Avoid error storm.
+               exit;
+            end if;
+         end loop;
+         --  Shift (position 1 is the MSB).
+         for I in 1 .. Nlen loop
+            Set_Element_String8 (Id, I,
+                                 Element_String8 (Id, I + Old_Len - Nlen));
+         end loop;
+         Resize_String8 (Nlen);
+         Set_String_Length (Lit, Nlen);
+
+      else
+         --  LRM08 15.8
+         --  -- If the length is equal to the number of characters in the
+         --     expanded bit value, the string literal value is the expanded
+         --     bit value itself.
+         null;
+      end if;
+   end Resize_Bit_String;
+
+   --  Precond : next token after tok_integer
+   --  postcond: likewise
+   --
+   --  Return an integer_literal or a physical_literal.
+   function Parse_Integer_Literal (Val : Iir_Int64) return Iir
+   is
+      Res : Iir;
+   begin
+      if Current_Token = Tok_Identifier then
+         -- physical literal
+         Res := Create_Iir (Iir_Kind_Physical_Int_Literal);
+         Set_Unit_Name (Res, Parse_Name (Allow_Indexes => False));
+      else
+         -- integer literal
+         Res := Create_Iir (Iir_Kind_Integer_Literal);
+      end if;
+      Set_Value (Res, Val);
+      return Res;
+   end Parse_Integer_Literal;
+
    --  precond : next token
    --  postcond: next token
    --
@@ -3987,16 +4157,8 @@ package body Parse is
             --  Skip integer
             Scan;
 
-            if Current_Token = Tok_Identifier then
-               -- physical literal
-               Res := Create_Iir (Iir_Kind_Physical_Int_Literal);
-               Set_Unit_Name (Res, Parse_Name (Allow_Indexes => False));
-            else
-               -- integer literal
-               Res := Create_Iir (Iir_Kind_Integer_Literal);
-            end if;
+            Res := Parse_Integer_Literal (Int);
             Set_Location (Res, Loc);
-            Set_Value (Res, Int);
             return Res;
 
          when Tok_Real =>
@@ -4043,23 +4205,39 @@ package body Parse is
             return Res;
          when Tok_New =>
             return Parse_Allocator;
+
+         when Tok_Integer_Letter =>
+            Int := Current_Iir_Int64;
+            Loc := Get_Token_Location;
+
+            --  Skip integer
+            Scan;
+
+            if Current_Token = Tok_Bit_String then
+               Res := Parse_Bit_String;
+
+               --  Skip bit string
+               Scan;
+
+               --  Resize.
+               Resize_Bit_String (Res, Nat32 (Int));
+            else
+               Error_Msg_Parse
+                 ("space is required between number and unit name",
+                  Get_Token_Location);
+               Res := Parse_Integer_Literal (Int);
+            end if;
+            Set_Location (Res, Loc);
+            return Res;
+
          when Tok_Bit_String =>
-            Res := Create_Iir (Iir_Kind_String_Literal8);
-            Set_Location (Res);
-            Set_String8_Id (Res, Current_String_Id);
-            Set_String_Length (Res, Current_String_Length);
-            case Current_Iir_Int64 is
-               when 1 =>
-                  Set_Bit_String_Base (Res, Base_2);
-               when 3 =>
-                  Set_Bit_String_Base (Res, Base_8);
-               when 4 =>
-                  Set_Bit_String_Base (Res, Base_16);
-               when others =>
-                  raise Internal_Error;
-            end case;
+            Res := Parse_Bit_String;
+
+            --  Skip bit string
             Scan;
+
             return Res;
+
          when Tok_Minus
            | Tok_Plus =>
             Error_Msg_Parse
diff --git a/src/vhdl/scanner.adb b/src/vhdl/scanner.adb
index 632e24081..02cd752fd 100644
--- a/src/vhdl/scanner.adb
+++ b/src/vhdl/scanner.adb
@@ -361,7 +361,7 @@ package body Scanner is
    begin
       --  String delimiter.
       Mark := Source (Pos);
-      pragma Assert (Mark = Quotation or else Mark = '%');
+      pragma Assert (Mark = '"' or else Mark = '%');
 
       Pos := Pos + 1;
       Length := 0;
@@ -427,40 +427,25 @@ package body Scanner is
    --
    --  The current character must be a base specifier, followed by '"' or '%'.
    --  The base must be valid.
-   procedure Scan_Bit_String
+   procedure Scan_Bit_String (Base_Log : Nat32)
    is
-      -- The base specifier.
-      Base_Log : Nat32 range 1 .. 4;
+      --  Position of character '0'.
+      Pos_0 : constant Nat8 := Character'Pos ('0');
+
+      --  Used for the base.
+      subtype Nat4 is Natural range 1 .. 4;
+      Base : constant Nat32 := 2 ** Nat4 (Base_Log);
+
       -- The quotation character (can be " or %).
-      Mark: Character;
+      Mark : constant Character := Source (Pos);
       -- Current character.
       C : Character;
       --  Current length.
       Length : Nat32;
       --  Digit value.
       V, D : Nat8;
-      --  Position of character '0'.
-      Pos_0 : constant Nat8 := Character'Pos ('0');
    begin
-      --  LRM93 13.7
-      --  A letter in a bit string literal (... or the base specificer) can be
-      --  written either in lowercase or in upper case, with the same meaning.
-      --
-      --  LRM08 15.8 Bit string literals
-      --  Not present!
-      case Source (Pos) is
-         when 'x' | 'X' =>
-            Base_Log := 4;
-         when 'o' | 'O' =>
-            Base_Log := 3;
-         when 'b' | 'B' =>
-            Base_Log := 1;
-         when others =>
-            raise Internal_Error;
-      end case;
-      Pos := Pos + 1;
-      Mark := Source (Pos);
-      pragma Assert (Mark = Quotation or else Mark = '%');
+      pragma Assert (Mark = '"' or else Mark = '%');
       Pos := Pos + 1;
       Length := 0;
       Current_Context.Str_Id := Str_Table.Create_String8;
@@ -512,47 +497,212 @@ package body Scanner is
                  ("'%' cannot close a bit string opened by '""'");
                exit;
             when others =>
+               if Characters_Kind (C) in Graphic_Character then
+                  if Vhdl_Std >= Vhdl_08 then
+                     V := Nat8'Last;
+                  else
+                     Error_Msg_Scan ("invalid character in bit string");
+                     --  Continue the bit string
+                     V := 0;
+                  end if;
+               else
+                  Error_Msg_Scan ("bit string not terminated");
+                  Pos := Pos - 1;
+                  exit;
+               end if;
+         end case;
+
+         --  Expand bit value.
+         if Vhdl_Std >= Vhdl_08 and V > Base then
+            --  Expand as graphic character.
+            for I in 1 .. Base_Log loop
+               Str_Table.Append_String8_Char (C);
+            end loop;
+         else
+            --  Expand as extended digits.
+            case Base_Log is
+               when 1 =>
+                  if V > 1 then
+                     Error_Msg_Scan
+                       ("invalid character in a binary bit string");
+                     V := 1;
+                  end if;
+                  Str_Table.Append_String8 (Pos_0 + V);
+               when 3 =>
+                  if V > 7 then
+                     Error_Msg_Scan
+                       ("invalid character in a octal bit string");
+                     V := 7;
+                  end if;
+                  for I in 1 .. 3 loop
+                     D := V / 4;
+                     Str_Table.Append_String8 (Pos_0 + D);
+                     V := (V - 4 * D) * 2;
+                  end loop;
+               when 4 =>
+                  for I in 1 .. 4 loop
+                     D := V / 8;
+                     Str_Table.Append_String8 (Pos_0 + D);
+                     V := (V - 8 * D) * 2;
+                  end loop;
+               when others =>
+                  raise Internal_Error;
+            end case;
+         end if;
+
+         Length := Length + Base_Log;
+      end loop;
+
+      if Length = 0 then
+         Error_Msg_Scan ("empty bit string is not allowed");
+      end if;
+      Current_Token := Tok_Bit_String;
+      Current_Context.Str_Len := Length;
+   end Scan_Bit_String;
+
+   procedure Scan_Dec_Bit_String
+   is
+      use Str_Table;
+
+      Id : String8_Id;
+
+      --  Position of character '0'.
+      Pos_0 : constant Nat8 := Character'Pos ('0');
+
+      -- Current character.
+      C : Character;
+      --  Current length.
+      Length : Nat32;
+      --  Digit value.
+      V, D : Nat8;
+
+      type Carries_Type is array (0 .. 3) of Nat8;
+      Carries : Carries_Type;
+      No_Carries : constant Carries_Type := (others => Pos_0);
+
+      --  Shift right carries.  Note the Carries (0) is the LSB.
+      procedure Shr_Carries is
+      begin
+         Carries := (Carries (1), Carries (2), Carries (3), Pos_0);
+      end Shr_Carries;
+
+      procedure Append_Carries is
+      begin
+         --  Expand the bit string.  Note that position 1 of the string8 is
+         --  the MSB.
+         while Carries /= No_Carries loop
+            Append_String8 (Pos_0);
+            Length := Length + 1;
+            for I in reverse 2 .. Length loop
+               Set_Element_String8 (Id, I, Element_String8 (Id, I - 1));
+            end loop;
+            Set_Element_String8 (Id, 1, Carries (0));
+            Shr_Carries;
+         end loop;
+      end Append_Carries;
+
+      procedure Add_One_To_Carries is
+      begin
+         for I in Carries'Range loop
+            if Carries (I) = Pos_0 then
+               Carries (I) := Pos_0 + 1;
+               --  End of propagation.
+               exit;
+            else
+               Carries (I) := Pos_0;
+               --  Continue propagation.
+            end if;
+         end loop;
+      end Add_One_To_Carries;
+   begin
+      pragma Assert (Source (Pos) = '"');
+      Pos := Pos + 1;
+      Length := 0;
+      Id := Create_String8;
+      Current_Context.Str_Id := Id;
+      loop
+         << Again >> null;
+         C := Source (Pos);
+         Pos := Pos + 1;
+         exit when C = '"';
+
+         if C in '0' .. '9' then
+            V := Character'Pos (C) - Character'Pos ('0');
+         elsif C = '_' then
+            if Source (Pos) = '_' then
+               Error_Msg_Scan
+                 ("double underscore not allowed in a bit string");
+            end if;
+            if Source (Pos - 2) = '"' then
+               Error_Msg_Scan
+                 ("underscore not allowed at the start of a bit string");
+            elsif Source (Pos) = '"' then
+               Error_Msg_Scan
+                 ("underscore not allowed at the end of a bit string");
+            end if;
+            goto Again;
+         else
+            if Characters_Kind (C) in Graphic_Character then
+               Error_Msg_Scan
+                 ("graphic character not allowed in decimal bit string");
+               --  Continue the bit string
+               V := 0;
+            else
                Error_Msg_Scan ("bit string not terminated");
                Pos := Pos - 1;
                exit;
-         end case;
+            end if;
+         end if;
 
-         case Base_Log is
-            when 1 =>
-               if V > 1 then
-                  Error_Msg_Scan ("invalid character in a binary bit string");
-                  V := 1;
-               end if;
-               Str_Table.Append_String8 (Pos_0 + V);
-            when 2 =>
-               raise Internal_Error;
-            when 3 =>
-               if V > 7 then
-                  Error_Msg_Scan ("invalid character in a octal bit string");
-                  V := 7;
-               end if;
-               for I in 1 .. 3 loop
-                  D := V / 4;
-                  Str_Table.Append_String8 (Pos_0 + D);
-                  V := (V - 4 * D) * 2;
-               end loop;
-            when 4 =>
-               for I in 1 .. 4 loop
-                  D := V / 8;
-                  Str_Table.Append_String8 (Pos_0 + D);
-                  V := (V - 8 * D) * 2;
+         --  Multiply by 10.
+         Carries := (others => Pos_0);
+         for I in reverse 1 .. Length loop
+            --  Shift by 1 (*2).
+            D := Element_String8 (Id, I);
+            Set_Element_String8 (Id, I, Carries (0));
+            Shr_Carries;
+            --  Add D and D * 4.
+            if D /= Pos_0 then
+               Add_One_To_Carries;
+               --  Add_Four_To_Carries:
+               for I in 2 .. 3 loop
+                  if Carries (I) = Pos_0 then
+                     Carries (I) := Pos_0 + 1;
+                     --  End of propagation.
+                     exit;
+                  else
+                     Carries (I) := Pos_0;
+                     --  Continue propagation.
+                  end if;
                end loop;
-         end case;
-         Length := Length + Base_Log;
+            end if;
+         end loop;
+         Append_Carries;
+
+         --  Add V.
+         for I in Carries'Range loop
+            D := V / 2;
+            Carries (I) := Pos_0 + (V - 2 * D);
+            V := D;
+         end loop;
+         for I in reverse 1 .. Length loop
+            D := Element_String8 (Id, I);
+            if D /= Pos_0 then
+               Add_One_To_Carries;
+            end if;
+            Set_Element_String8 (Id, I, Carries (0));
+            Shr_Carries;
+            exit when Carries = No_Carries;
+         end loop;
+         Append_Carries;
       end loop;
 
       if Length = 0 then
          Error_Msg_Scan ("empty bit string is not allowed");
       end if;
       Current_Token := Tok_Bit_String;
-      Current_Context.Int64 := Iir_Int64 (Base_Log);
       Current_Context.Str_Len := Length;
-   end Scan_Bit_String;
+   end Scan_Dec_Bit_String;
 
    -- LRM93 13.3.1
    -- Basic Identifiers
@@ -632,6 +782,7 @@ package body Scanner is
          Len := Len - 1;
          C := '_';
       end if;
+      Name_Length := Len;
 
       -- LRM93 13.2
       -- At least one separator is required between an identifier or an
@@ -641,17 +792,63 @@ package body Scanner is
            | Upper_Case_Letter
            | Lower_Case_Letter =>
             raise Internal_Error;
-         when Other_Special_Character =>
-            if Vhdl_Std /= Vhdl_87 and then C = '\' then
+         when Other_Special_Character | Special_Character =>
+            if (C = '"' or C = '%') and then Len <= 2 then
+               --  Good candidate for bit string.
+
+               --  LRM93 13.7
+               --  BASE_SPECIFIER ::= B | O | X
+               --
+               --  A letter in a bit string literal (either an extended digit
+               --  or the base specifier) can be written either in lower case
+               --  or in upper case, with the same meaning.
+               --
+               --  LRM08 15.8 Bit string literals
+               --  BASE_SPECICIER ::=
+               --     B | O | X | UB | UO | UX | SB | SO | SX | D
+               --
+               --  An extended digit and the base specifier in a bit string
+               --  literal can be written either in lowercase or in uppercase,
+               --  with the same meaning.
+               declare
+                  Base : Nat32;
+                  Cl : constant Character := Name_Buffer (Len);
+                  Cf : constant Character := Name_Buffer (1);
+               begin
+                  if Cl = 'b' then
+                     Base := 1;
+                  elsif Cl = 'o' then
+                     Base := 3;
+                  elsif Cl = 'x' then
+                     Base := 4;
+                  elsif Vhdl_Std >= Vhdl_08 and Len = 1 and Cf = 'd' then
+                     Scan_Dec_Bit_String;
+                     return;
+                  else
+                     Base := 0;
+                  end if;
+                  if Base > 0 then
+                     if Len = 1 then
+                        Scan_Bit_String (Base);
+                        return;
+                     elsif Vhdl_Std >= Vhdl_08
+                       and then (Cf = 's' or Cf = 'u')
+                     then
+                        Scan_Bit_String (Base);
+                        return;
+                     end if;
+                  end if;
+               end;
+            end if;
+            if Vhdl_Std > Vhdl_87 and then C = '\' then
+               --  Start of extended identifier.  Cannot follow an identifier.
                Error_Separator;
             end if;
          when Invalid
            | Format_Effector
-           | Space_Character
-           | Special_Character =>
+           | Space_Character =>
             null;
       end case;
-      Name_Length := Len;
 
       -- Hash it.
       Current_Context.Identifier := Name_Table.Get_Identifier;
@@ -1379,7 +1576,7 @@ package body Scanner is
          when '0' .. '9' =>
             Scan_Literal;
 
-            --  LRM 13.2
+            --  LRM93 13.2
             --  At least one separator is required between an identifier or
             --  an abstract literal and an adjacent identifier or abstract
             --  literal.
@@ -1390,13 +1587,19 @@ package body Scanner is
                  | Lower_Case_Letter =>
                   --  Could call Error_Separator, but use a clearer message
                   --  for this common case.
-                  --  Note: the term "unit name" is not correct here, since it
-                  --  can be any identifier or even a keyword; however it is
-                  --  probably the most common case (eg 10ns).
-                  Error_Msg_Scan
-                    ("space is required between number and unit name");
+                  --  Note: the term "unit name" is not correct here, since
+                  --  it can be any identifier or even a keyword; however it
+                  --  is probably the most common case (eg 10ns).
+                  if Vhdl_Std >= Vhdl_08 and then Current_Token = Tok_Integer
+                  then
+                     Current_Token := Tok_Integer_Letter;
+                  else
+                     Error_Msg_Scan
+                       ("space is required between number and unit name");
+                  end if;
                when Other_Special_Character =>
-                  if Vhdl_Std /= Vhdl_87 and then Source (Pos) = '\' then
+                  if Vhdl_Std > Vhdl_87 and then Source (Pos) = '\' then
+                     --  Start of extended identifier.
                      Error_Separator;
                   end if;
                when Invalid
@@ -1555,20 +1758,7 @@ package body Scanner is
             Error_Msg_Scan ("an identifier can't start with '_'");
             Pos := Pos + 1;
             goto Again;
-         when 'B' | 'b' | 'O' | 'o' | 'X' | 'x' =>
-            if Source (Pos + 1) = Quotation or else Source (Pos + 1) = '%' then
-               -- LRM93 13.7
-               -- BASE_SPECIFIER ::= B | O | X
-               -- A letter in a bit string literal (either an extended digit or
-               -- the base specifier) can be written either in lower case or
-               -- in upper case, with the same meaning.
-               Scan_Bit_String;
-            else
-               Scan_Identifier;
-            end if;
-            return;
-         when 'A' | 'C' .. 'N' | 'P' .. 'W' | 'Y'| 'Z'
-           | 'a' | 'c' .. 'n' | 'p' .. 'w' | 'y'| 'z' =>
+         when 'A' .. 'Z' | 'a' .. 'z' =>
             Scan_Identifier;
             return;
          when UC_A_Grave .. UC_O_Diaeresis
diff --git a/src/vhdl/sem_expr.adb b/src/vhdl/sem_expr.adb
index 16add4fdc..af59a3ae3 100644
--- a/src/vhdl/sem_expr.adb
+++ b/src/vhdl/sem_expr.adb
@@ -1897,6 +1897,12 @@ package body Sem_Expr is
             end if;
             Inter := Get_Next_Interpretation (Inter);
          end loop;
+
+         --  LRM08 9.3 Operands
+         --  The character literals corresponding to the graphic characters
+         --  contained within a string literal or a bit string literal shall
+         --  be visible at the place of the string literal.
+
          --  Character C is not visible...
          if Find_Name_In_List (Get_Enumeration_Literal_List (Etype), Id)
            = Null_Iir
@@ -1919,55 +1925,31 @@ package body Sem_Expr is
       El : Iir;
       Enum_Pos : Iir_Int32;
       Ch : Character;
-   begin
-      if Get_Bit_String_Base (Str) /= Base_None then
-         --  A bit string.
-         declare
-            Map : Characters_Pos ('0' .. '1');
-         begin
-            for C in Character range '0' .. '1' loop
-               El := Find_Literal (El_Type, C);
-               if El = Null_Iir then
-                  Enum_Pos := 0;
-               else
-                  Enum_Pos := Get_Enum_Pos (El);
-               end if;
-               Map (C) := Nat8 (Enum_Pos);
-            end loop;
 
-            for I in 1 .. Len loop
-               Ch := Str_Table.Char_String8 (Id, I);
-               pragma Assert (Ch in Map'Range);
-               Str_Table.Set_Element_String8 (Id, I, Map (Ch));
-            end loop;
-         end;
-      else
-         --  A string.
-         declare
-            --  Create a cache of literals, to speed-up a little bit the
-            --  search.
-            No_Pos : constant Nat8 := Nat8'Last;
-            Map : Characters_Pos (' ' .. Character'Last) := (others => No_Pos);
-            Res : Nat8;
-         begin
-            for I in 1 .. Len loop
-               Ch := Str_Table.Char_String8 (Id, I);
-               Res := Map (Ch);
-               if Res = No_Pos then
-                  El := Find_Literal (El_Type, Ch);
-                  if El = Null_Iir then
-                     Res := 0;
-                  else
-                     Enum_Pos := Get_Enum_Pos (El);
-                     Res := Nat8 (Enum_Pos);
-                     Map (Ch) := Res;
-                  end if;
-               end if;
-               Str_Table.Set_Element_String8 (Id, I, Res);
-            end loop;
-         end;
-      end if;
+      --  Create a cache of literals, to speed-up a little bit the
+      --  search.
+      No_Pos : constant Nat8 := Nat8'Last;
+      Map : Characters_Pos (' ' .. Character'Last) := (others => No_Pos);
+      Res : Nat8;
+   begin
+      for I in 1 .. Len loop
+         Ch := Str_Table.Char_String8 (Id, I);
+         Res := Map (Ch);
+         if Res = No_Pos then
+            El := Find_Literal (El_Type, Ch);
+            if El = Null_Iir then
+               Res := 0;
+            else
+               Enum_Pos := Get_Enum_Pos (El);
+               Res := Nat8 (Enum_Pos);
+               Map (Ch) := Res;
+            end if;
+         end if;
+         Str_Table.Set_Element_String8 (Id, I, Res);
+      end loop;
 
+      --  LRM08 9.4.2 Locally static primaries
+      --  a) A literal of any type other than type TIME
       Set_Expr_Staticness (Str, Locally);
 
       return Natural (Len);
diff --git a/src/vhdl/tokens.adb b/src/vhdl/tokens.adb
index f74112721..904bd7d71 100644
--- a/src/vhdl/tokens.adb
+++ b/src/vhdl/tokens.adb
@@ -61,7 +61,8 @@ package body Tokens is
             return "<character>";
          when Tok_Identifier =>
             return "<identifier>";
-         when Tok_Integer =>
+         when Tok_Integer
+           | Tok_Integer_Letter =>
             return "<integer>";
          when Tok_Real =>
             return "<real>";
diff --git a/src/vhdl/tokens.ads b/src/vhdl/tokens.ads
index bd313e2d1..adbccb2fc 100644
--- a/src/vhdl/tokens.ads
+++ b/src/vhdl/tokens.ads
@@ -47,8 +47,17 @@ package Tokens is
        Tok_Integer,
        Tok_Real,
        Tok_String,
+
+       --  This token corresponds to a base specifier followed by bit_value.
+       --  The base specifier is stored in Name_Buffer/Name_Length like an
+       --  identifier (in lowercase), the String8_Id contains the expanded bit
+       --  value.
        Tok_Bit_String,
 
+       --  An integer immediately followed by a letter.  This is used by to
+       --  scan vhdl 2008 (and later) bit string with a length.
+       Tok_Integer_Letter,
+
    -- relational_operator
        Tok_Equal,               -- =
        Tok_Not_Equal,           -- /=