Pass time-resolution to grt.

Use time-resolution for Put_Time.
Use time-resolution for --stop-time (Parse_Time).
Use time-resolution as VpiTimePrecision and for vcd.
TODO: ghw (but needs to update ghwlib and gtkwave)

Fix #672

7 files changed, 97 insertions, 43 deletions

diff --git a/src/grt/grt-astdio.adb b/src/grt/grt-astdio.adb
index a572dd3cc..5fdcd1a64 100644
--- a/src/grt/grt-astdio.adb
+++ b/src/grt/grt-astdio.adb
@@ -23,6 +23,7 @@
 --  however invalidate any other reasons why the executable file might be
 --  covered by the GNU Public License.
 with Grt.C; use Grt.C;
+with Grt.Options;
 
 package body Grt.Astdio is
    procedure Put (Stream : FILEs; Str : String)
@@ -209,28 +210,37 @@ package body Grt.Astdio is
       end case;
    end Put_Dir;
 
-   procedure Put_Time (Stream : FILEs; Time : Std_Time) is
+   procedure Put_Time (Stream : FILEs; Time : Std_Time)
+   is
+      use Grt.Options;
+      Unit : Natural_Time_Scale;
+      T : Std_Time;
    begin
       if Time = Std_Time'First then
          Put (Stream, "-Inf");
       else
          --  Do not bother with sec, min, and hr.
-         if (Time mod 1_000_000_000_000) = 0 then
-            Put_I64 (Stream, Ghdl_I64 (Time / 1_000_000_000_000));
-            Put (Stream, "ms");
-         elsif (Time mod 1_000_000_000) = 0 then
-            Put_I64 (Stream, Ghdl_I64 (Time / 1_000_000_000));
-            Put (Stream, "us");
-         elsif (Time mod 1_000_000) = 0 then
-            Put_I64 (Stream, Ghdl_I64 (Time / 1_000_000));
-            Put (Stream, "ns");
-         elsif (Time mod 1_000) = 0 then
-            Put_I64 (Stream, Ghdl_I64 (Time / 1_000));
-            Put (Stream, "ps");
-         else
-            Put_I64 (Stream, Ghdl_I64 (Time));
-            Put (Stream, "fs");
-         end if;
+         Unit := Time_Resolution_Scale;
+         T := Time;
+         while Unit > 1 and then (T mod 1_000) = 0 loop
+            T := T / 1000;
+            Unit := Unit - 1;
+         end loop;
+         Put_I64 (Stream, Ghdl_I64 (T));
+         case Unit is
+            when 0 =>
+               Put (Stream, "sec");
+            when 1 =>
+               Put (Stream, "ms");
+            when 2 =>
+               Put (Stream, "us");
+            when 3 =>
+               Put (Stream, "ns");
+            when 4 =>
+               Put (Stream, "ps");
+            when 5 =>
+               Put (Stream, "fs");
+         end case;
       end if;
    end Put_Time;
 
diff --git a/src/grt/grt-disp.adb b/src/grt/grt-disp.adb
index e68b1168b..36644bf1a 100644
--- a/src/grt/grt-disp.adb
+++ b/src/grt/grt-disp.adb
@@ -54,14 +54,12 @@ package body Grt.Disp is
    --   Put_Str_Len (Stream, Type_Desc.E32.Values (Natural (E32)));
    --end Put_E32;
 
-   procedure Put_Sig_Index (Sig : Sig_Table_Index)
-   is
+   procedure Put_Sig_Index (Sig : Sig_Table_Index) is
    begin
       Put_I32 (stdout, Ghdl_I32 (Sig));
    end Put_Sig_Index;
 
-   procedure Put_Sig_Range (Sig : Sig_Table_Range)
-   is
+   procedure Put_Sig_Range (Sig : Sig_Table_Range) is
    begin
       Put_Sig_Index (Sig.First);
       if Sig.Last /= Sig.First then
@@ -70,8 +68,7 @@ package body Grt.Disp is
       end if;
    end Put_Sig_Range;
 
-   procedure Disp_Now
-   is
+   procedure Disp_Now is
    begin
       Put ("Now is ");
       Put_Time (stdout, Current_Time);
@@ -80,8 +77,7 @@ package body Grt.Disp is
       New_Line;
    end Disp_Now;
 
-   procedure Disp_Propagation_Kind (Kind : Propagation_Kind_Type)
-   is
+   procedure Disp_Propagation_Kind (Kind : Propagation_Kind_Type) is
    begin
       case Kind is
          when Drv_One_Driver =>
@@ -184,8 +180,7 @@ package body Grt.Disp is
       end loop;
    end Disp_Signals_Order;
 
-   procedure Disp_Mode (Mode : Mode_Type)
-   is
+   procedure Disp_Mode (Mode : Mode_Type) is
    begin
       case Mode is
          when Mode_B1 =>
diff --git a/src/grt/grt-options.adb b/src/grt/grt-options.adb
index cdf6c2886..5b154e4a5 100644
--- a/src/grt/grt-options.adb
+++ b/src/grt/grt-options.adb
@@ -117,6 +117,7 @@ package body Grt.Options is
       Pos : Natural;
       Time : Integer_64;
       Unit : String (1 .. 3);
+      Scale : Natural_Time_Scale;
    begin
       Extract_Integer (Str, Ok, Time, Pos);
       if not Ok then
@@ -138,27 +139,33 @@ package body Grt.Options is
       Unit (2) := To_Lower (Str (Pos + 1));
 
       if Unit = "fs " then
-         null;
+         Scale := 5;
       elsif Unit = "ps " then
-         Time := Time * (10 ** 3);
+         Scale := 4;
       elsif Unit = "ns " then
-         Time := Time * (10 ** 6);
+         Scale := 3;
       elsif Unit = "us " then
-         Time := Time * (10 ** 9);
+         Scale := 2;
       elsif Unit = "ms " then
-         Time := Time * (10 ** 12);
+         Scale := 1;
       elsif Unit = "sec" then
-         Time := Time * (10 ** 15);
-      elsif Unit = "min" then
-         Time := Time * (10 ** 15) * 60;
-      elsif Unit = "hr " then
-         Time := Time * (10 ** 15) * 3600;
+         Scale := 0;
       else
          Error_S ("bad unit name for '");
          Diag_C (Str);
          Error_E ("'");
          return -1;
       end if;
+      if Scale > Time_Resolution_Scale then
+         Error_S ("unit for '");
+         Diag_C (Str);
+         Error_E ("' is less than time resolution");
+         return -1;
+      end if;
+      while Scale < Time_Resolution_Scale loop
+         Time := Time * 1000;
+         Scale := Scale + 1;
+      end loop;
       return Std_Time (Time);
    end Parse_Time;
 
@@ -361,6 +368,23 @@ package body Grt.Options is
       Len : Natural;
       Status : Decode_Option_Status;
    begin
+      case Flag_String (5) is
+         when 'f' | '-' =>
+            Time_Resolution_Scale := 5;
+         when 'p' =>
+            Time_Resolution_Scale := 4;
+         when 'n' =>
+            Time_Resolution_Scale := 3;
+         when 'u' =>
+            Time_Resolution_Scale := 2;
+         when 'm' =>
+            Time_Resolution_Scale := 1;
+         when 's' =>
+            Time_Resolution_Scale := 0;
+         when others =>
+            Error ("unhandled time resolution");
+      end case;
+
       Stop := False;
       Last_Opt := Argc - 1;
       for I in 1 .. Argc - 1 loop
diff --git a/src/grt/grt-options.ads b/src/grt/grt-options.ads
index 4f24793f0..fa7e1f660 100644
--- a/src/grt/grt-options.ads
+++ b/src/grt/grt-options.ads
@@ -55,6 +55,16 @@ package Grt.Options is
    Flag_String : constant String (1 .. 5);
    pragma Import (C, Flag_String, "__ghdl_flag_string");
 
+   --  Time resolution extracted from Flag_String, in multiple of -3:
+   --  0: sec
+   --  1: ms
+   --  2: us
+   --  3: ns
+   --  4: ps
+   --  5: fs
+   subtype Natural_Time_Scale is Natural range 0 .. 5;
+   Time_Resolution_Scale : Natural_Time_Scale;
+
    --  Display options help.
    --  Should not be called directly.
    procedure Help;
diff --git a/src/grt/grt-vcd.adb b/src/grt/grt-vcd.adb
index 9050a26a4..b058dcdaf 100644
--- a/src/grt/grt-vcd.adb
+++ b/src/grt/grt-vcd.adb
@@ -53,6 +53,7 @@ with Grt.Vstrings;
 with Grt.Wave_Opt; use Grt.Wave_Opt;
 with Grt.Wave_Opt.Design; use Grt.Wave_Opt.Design;
 with Grt.Fcvt;
+with Grt.Options;
 pragma Elaborate_All (Grt.Table);
 
 package body Grt.Vcd is
@@ -241,7 +242,20 @@ package body Grt.Vcd is
       Vcd_Putline ("  GHDL v0");
       Vcd_Put_End;
       Vcd_Putline ("$timescale");
-      Vcd_Putline ("  1 fs");
+      case Options.Time_Resolution_Scale is
+         when 5 =>
+            Vcd_Putline ("  1 fs");
+         when 4 =>
+            Vcd_Putline ("  1 ps");
+         when 3 =>
+            Vcd_Putline ("  1 ns");
+         when 2 =>
+            Vcd_Putline ("  1 us");
+         when 1 =>
+            Vcd_Putline ("  1 ms");
+         when 0 =>
+            Vcd_Putline ("  1 sec");
+      end case;
       Vcd_Put_End;
    end Vcd_Init;
 
diff --git a/src/grt/grt-vpi.adb b/src/grt/grt-vpi.adb
index 4efa39584..ee6a9fdf5 100644
--- a/src/grt/grt-vpi.adb
+++ b/src/grt/grt-vpi.adb
@@ -325,7 +325,7 @@ package body Grt.Vpi is
          raise Program_Error;
       end if;
       Res := Std_Time (Unsigned_64 (V.mHigh) * 2 ** 32 + Unsigned_64 (V.mLow));
-      return Res * 1000;
+      return Res;
    end Vpi_Time_To_Time;
 
 -------------------------------------------------------------------------------
@@ -479,7 +479,7 @@ package body Grt.Vpi is
          when vpiType =>
             Res := Ref.mType;
          when vpiTimePrecision =>
-            Res := -12; -- In ps.
+            Res := -3 * Options.Time_Resolution_Scale;
          when vpiSize =>
             Res := Vpi_Get_Size (Ref);
          when vpiVector =>
@@ -1148,7 +1148,7 @@ package body Grt.Vpi is
 
       Res := Current_Time;
 
-      V := To_Unsigned_64 (Res) / 1000;
+      V := To_Unsigned_64 (Res);
       Time.mHigh := Unsigned_32 (V / 2 ** 32);
       Time.mLow  := Unsigned_32 (V mod 2 ** 32);
       Time.mReal := 0.0;
diff --git a/src/grt/grt-waves.adb b/src/grt/grt-waves.adb
index e1931bfa2..c0d12993f 100644
--- a/src/grt/grt-waves.adb
+++ b/src/grt/grt-waves.adb
@@ -318,8 +318,7 @@ package body Grt.Waves is
       end if;
    end Wave_Init;
 
-   procedure Write_File_Header
-   is
+   procedure Write_File_Header is
    begin
       --  Magic, 9 bytes.
       Wave_Put ("GHDLwave" & Nl);
@@ -331,6 +330,8 @@ package body Grt.Waves is
       Wave_Put_Byte (1);
 
       Wave_Write_Size_Order;
+
+      --  TODO: add time resolution.
    end Write_File_Header;
 
    procedure Avhpi_Error (Err : AvhpiErrorT)