synth: minor refactoring.

3 files changed, 38 insertions, 2 deletions

diff --git a/src/synth/netlists-folds.adb b/src/synth/netlists-folds.adb
index 01c210656..e591c35cf 100644
--- a/src/synth/netlists-folds.adb
+++ b/src/synth/netlists-folds.adb
@@ -231,8 +231,7 @@ package body Netlists.Folds is
                Sh : constant Natural := Natural (Width'Min (Wn, W));
             begin
                V := Get_Net_Uns64 (I);
-               V := Shift_Left (V, 64 - Sh);
-               V := Shift_Right_Arithmetic (V, 64 - Sh);
+               V := Sext (V, Sh);
                Res := Build2_Const_Int (Ctxt, To_Int64 (V), W);
             end;
          else
diff --git a/src/synth/types_utils.adb b/src/synth/types_utils.adb
new file mode 100644
index 000000000..861827520
--- /dev/null
+++ b/src/synth/types_utils.adb
@@ -0,0 +1,33 @@
+--  Utils for common types.
+--  Copyright (C) 2019 Tristan Gingold
+--
+--  GHDL is free software; you can redistribute it and/or modify it under
+--  the terms of the GNU General Public License as published by the Free
+--  Software Foundation; either version 2, or (at your option) any later
+--  version.
+--
+--  GHDL is distributed in the hope that it will be useful, but WITHOUT ANY
+--  WARRANTY; without even the implied warranty of MERCHANTABILITY or
+--  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+--  for more details.
+--
+--  You should have received a copy of the GNU General Public License
+--  along with GHDL; see the file COPYING.  If not, write to the Free
+--  Software Foundation, 59 Temple Place - Suite 330, Boston, MA
+--  02111-1307, USA.
+
+package body Types_Utils is
+   function Sext (V : Uns64; Sz : Natural) return Uns64
+   is
+      Sh : constant Natural range 0 .. 64 := 64 - Sz;
+   begin
+      return Shift_Right_Arithmetic (Shift_Left (V, Sh), Sh);
+   end Sext;
+
+   function Sext (V : Uns32; Sz : Natural) return Uns32
+   is
+      Sh : constant Natural range 0 .. 32 := 32 - Sz;
+   begin
+      return Shift_Right_Arithmetic (Shift_Left (V, Sh), Sh);
+   end Sext;
+end Types_Utils;
diff --git a/src/synth/types_utils.ads b/src/synth/types_utils.ads
index 71bdf5399..04196e11c 100644
--- a/src/synth/types_utils.ads
+++ b/src/synth/types_utils.ads
@@ -35,4 +35,8 @@ package Types_Utils is
 
    function To_Uns64 is new Ada.Unchecked_Conversion
      (Fp64, Uns64);
+
+   --  Sign extend V: bit SZ is copied to bits SZ + 1 .. 63/31.
+   function Sext (V : Uns64; Sz : Natural) return Uns64;
+   function Sext (V : Uns32; Sz : Natural) return Uns32;
 end Types_Utils;