Add minimal GNAT run time system (RTS)

Add a stripped-down version of libgnat. This is somehow comparable to
libgcc but for Ada programs. It's licensed under GPLv3 but with the
runtime library exception. So it's totally fine to link it with our
GPLv2 code and keep it under GPLv2.

Change-Id: Ie6522abf093f0a516b9ae18ddc69131bd721dc0c
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/11836
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: Edward O'Callaghan <edward.ocallaghan@koparo.com>

1 files changed, 131 insertions, 0 deletions

diff --git a/src/lib/gnat/s-stoele.adb b/src/lib/gnat/s-stoele.adb
new file mode 100644
index 0000000000..1cb5f92a23
--- /dev/null
+++ b/src/lib/gnat/s-stoele.adb
@@ -0,0 +1,131 @@
+------------------------------------------------------------------------------
+--                                                                          --
+--                         GNAT COMPILER COMPONENTS                         --
+--                                                                          --
+--               S Y S T E M . S T O R A G E _ E L E M E N T S              --
+--                                                                          --
+--                                 B o d y                                  --
+--                                                                          --
+--          Copyright (C) 1992-2014, Free Software Foundation, Inc.         --
+--                                                                          --
+-- GNAT is free software;  you can  redistribute it  and/or modify it under --
+-- terms of the  GNU General Public License as published  by the Free Soft- --
+-- ware  Foundation;  either version 3,  or (at your option) any later ver- --
+-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
+-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
+-- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
+--                                                                          --
+-- As a special exception under Section 7 of GPL version 3, you are granted --
+-- additional permissions described in the GCC Runtime Library Exception,   --
+-- version 3.1, as published by the Free Software Foundation.               --
+--                                                                          --
+-- You should have received a copy of the GNU General Public License and    --
+-- a copy of the GCC Runtime Library Exception along with this program;     --
+-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
+-- <http://www.gnu.org/licenses/>.                                          --
+--                                                                          --
+-- GNAT was originally developed  by the GNAT team at  New York University. --
+-- Extensive contributions were provided by Ada Core Technologies Inc.      --
+--                                                                          --
+------------------------------------------------------------------------------
+
+pragma Compiler_Unit_Warning;
+
+with Ada.Unchecked_Conversion;
+
+package body System.Storage_Elements is
+
+   pragma Suppress (All_Checks);
+
+   --  Conversion to/from address
+
+   --  Note qualification below of To_Address to avoid ambiguities systems
+   --  where Address is a visible integer type.
+
+   function To_Address is
+     new Ada.Unchecked_Conversion (Storage_Offset, Address);
+   function To_Offset  is
+     new Ada.Unchecked_Conversion (Address, Storage_Offset);
+
+   --  Conversion to/from integers
+
+   --  These functions must be place first because they are inlined_always
+   --  and are used and inlined in other subprograms defined in this unit.
+
+   ----------------
+   -- To_Address --
+   ----------------
+
+   function To_Address (Value : Integer_Address) return Address is
+   begin
+      return Address (Value);
+   end To_Address;
+
+   ----------------
+   -- To_Integer --
+   ----------------
+
+   function To_Integer (Value : Address) return Integer_Address is
+   begin
+      return Integer_Address (Value);
+   end To_Integer;
+
+   --  Address arithmetic
+
+   ---------
+   -- "+" --
+   ---------
+
+   function "+" (Left : Address; Right : Storage_Offset) return Address is
+   begin
+      return Storage_Elements.To_Address
+        (To_Integer (Left) + To_Integer (To_Address (Right)));
+   end "+";
+
+   function "+" (Left : Storage_Offset; Right : Address) return Address is
+   begin
+      return Storage_Elements.To_Address
+        (To_Integer (To_Address (Left)) + To_Integer (Right));
+   end "+";
+
+   ---------
+   -- "-" --
+   ---------
+
+   function "-" (Left : Address; Right : Storage_Offset) return Address is
+   begin
+      return Storage_Elements.To_Address
+        (To_Integer (Left) - To_Integer (To_Address (Right)));
+   end "-";
+
+   function "-" (Left, Right : Address) return Storage_Offset is
+   begin
+      return To_Offset (Storage_Elements.To_Address
+                         (To_Integer (Left) - To_Integer (Right)));
+   end "-";
+
+   -----------
+   -- "mod" --
+   -----------
+
+   function "mod"
+     (Left  : Address;
+      Right : Storage_Offset) return Storage_Offset
+   is
+   begin
+      if Right > 0 then
+         return Storage_Offset
+           (To_Integer (Left) mod Integer_Address (Right));
+
+         --  The negative case makes no sense since it is a case of a mod where
+         --  the left argument is unsigned and the right argument is signed. In
+         --  accordance with the (spirit of the) permission of RM 13.7.1(16),
+         --  we raise CE, and also include the zero case here. Yes, the RM says
+         --  PE, but this really is so obviously more like a constraint error.
+
+      else
+         raise Constraint_Error;
+      end if;
+   end "mod";
+
+end System.Storage_Elements;