synth: implement static sub_sgn_int. Fix #1265

3 files changed, 50 insertions, 0 deletions

diff --git a/src/synth/synth-ieee-numeric_std.adb b/src/synth/synth-ieee-numeric_std.adb
index 96a228bb3..7c132dd8e 100644
--- a/src/synth/synth-ieee-numeric_std.adb
+++ b/src/synth/synth-ieee-numeric_std.adb
@@ -211,6 +211,37 @@ package body Synth.Ieee.Numeric_Std is
       return Res;
    end Sub_Uns_Nat;
 
+   function Sub_Sgn_Int (L : Std_Logic_Vector; R : Int64)
+                        return Std_Logic_Vector
+   is
+      pragma Assert (L'First = 1);
+      Res : Std_Logic_Vector (1 .. L'Last);
+      V : Uns64;
+      Lb, Rb, Carry : Sl_X01;
+   begin
+      if L'Last < 1 then
+         return Null_Vec;
+      end if;
+      V := To_Uns64 (R);
+      Carry := '1';
+      for I in reverse Res'Range loop
+         Lb := Sl_To_X01 (L (I));
+         Rb := Uns_To_01 (V and 1);
+         Rb := Not_Table (Rb);
+         if Lb = 'X' then
+            --assert NO_WARNING
+            --  report "NUMERIC_STD.""+"": non logical value detected"
+            --  severity warning;
+            Res := (others => 'X');
+            exit;
+         end if;
+         Res (I) := Compute_Sum (Carry, Rb, Lb);
+         Carry := Compute_Carry (Carry, Rb, Lb);
+         V := Shift_Right_Arithmetic (V, 1);
+      end loop;
+      return Res;
+   end Sub_Sgn_Int;
+
    function Mul_Uns_Uns (L, R : Std_Logic_Vector) return Std_Logic_Vector
    is
       pragma Assert (L'First = 1);
diff --git a/src/synth/synth-ieee-numeric_std.ads b/src/synth/synth-ieee-numeric_std.ads
index 7e85f04a0..31beea86f 100644
--- a/src/synth/synth-ieee-numeric_std.ads
+++ b/src/synth/synth-ieee-numeric_std.ads
@@ -36,6 +36,8 @@ package Synth.Ieee.Numeric_Std is
 
    function Sub_Uns_Uns (L, R : Std_Logic_Vector) return Std_Logic_Vector;
 
+   function Sub_Sgn_Int (L : Std_Logic_Vector; R : Int64)
+                        return Std_Logic_Vector;
    function Sub_Uns_Nat (L : Std_Logic_Vector; R : Uns64)
                         return Std_Logic_Vector;
 
diff --git a/src/synth/synth-static_oper.adb b/src/synth/synth-static_oper.adb
index b387ae8de..5f1316745 100644
--- a/src/synth/synth-static_oper.adb
+++ b/src/synth/synth-static_oper.adb
@@ -410,6 +410,20 @@ package body Synth.Static_Oper is
       end;
    end Synth_Sub_Uns_Nat;
 
+   function Synth_Sub_Sgn_Int (L, R : Memtyp; Loc : Syn_Src) return Memtyp
+   is
+      pragma Unreferenced (Loc);
+      L_Arr : Std_Logic_Vector (1 .. Natural (Vec_Length (L.Typ)));
+      R_Val : constant Int64 := Read_Discrete (R);
+   begin
+      To_Std_Logic_Vector (L, L_Arr);
+      declare
+         Res_Arr : constant Std_Logic_Vector := Sub_Sgn_Int (L_Arr, R_Val);
+      begin
+         return To_Memtyp (Res_Arr, L.Typ.Vec_El);
+      end;
+   end Synth_Sub_Sgn_Int;
+
    function Synth_Mul_Uns_Uns (L, R : Memtyp; Loc : Syn_Src) return Memtyp
    is
       pragma Unreferenced (Loc);
@@ -892,6 +906,9 @@ package body Synth.Static_Oper is
          when Iir_Predefined_Ieee_Numeric_Std_Sub_Uns_Nat =>
             return Synth_Sub_Uns_Nat (Left, Right, Expr);
 
+         when Iir_Predefined_Ieee_Numeric_Std_Sub_Sgn_Int =>
+            return Synth_Sub_Sgn_Int (Left, Right, Expr);
+
          when Iir_Predefined_Ieee_Numeric_Std_Mul_Uns_Uns =>
             return Synth_Mul_Uns_Uns (Left, Right, Expr);
          when Iir_Predefined_Ieee_Numeric_Std_Mul_Nat_Uns =>