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, 176 insertions, 0 deletions

diff --git a/src/lib/gnat/system.ads b/src/lib/gnat/system.ads
new file mode 100644
index 0000000000..aed5592f73
--- /dev/null
+++ b/src/lib/gnat/system.ads
@@ -0,0 +1,176 @@
+------------------------------------------------------------------------------
+--                                                                          --
+--                        GNAT RUN-TIME COMPONENTS                          --
+--                                                                          --
+--                               S Y S T E M                                --
+--                                                                          --
+--                                 S p e c                                  --
+--                              (LSH Version)                               --
+--                                                                          --
+--          Copyright (C) 1992-2014, Free Software Foundation, Inc.         --
+--                                                                          --
+-- This specification is derived from the Ada Reference Manual for use with --
+-- GNAT. The copyright notice above, and the license provisions that follow --
+-- apply solely to the  contents of the part following the private keyword. --
+--                                                                          --
+-- 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 Restrictions (No_Exception_Propagation);
+pragma Restrictions (No_Exception_Registration);
+
+pragma Restrictions (No_Implicit_Dynamic_Code);
+pragma Restrictions (No_Finalization);
+pragma Restrictions (No_Tasking);
+
+package System is
+   pragma Pure;
+   --  Note that we take advantage of the implementation permission to make
+   --  this unit Pure instead of Preelaborable; see RM 13.7.1(15). In Ada
+   --  2005, this is Pure in any case (AI-362).
+
+   pragma No_Elaboration_Code_All;
+   --  Allow the use of that restriction in units that WITH this unit
+
+   type Name is (SYSTEM_NAME_GNAT);
+   System_Name : constant Name := SYSTEM_NAME_GNAT;
+
+   --  System-Dependent Named Numbers
+
+   Min_Int               : constant := Long_Long_Integer'First;
+   Max_Int               : constant := Long_Long_Integer'Last;
+
+   Max_Binary_Modulus    : constant := 2 ** Long_Long_Integer'Size;
+   Max_Nonbinary_Modulus : constant := 2 ** Integer'Size - 1;
+
+   Max_Base_Digits       : constant := Long_Long_Float'Digits;
+   Max_Digits            : constant := Long_Long_Float'Digits;
+
+   Max_Mantissa          : constant := 63;
+   Fine_Delta            : constant := 2.0 ** (-Max_Mantissa);
+
+   Tick                  : constant := 0.01;
+
+   --  Storage-related Declarations
+
+   type Address is private;
+   --  Note that we do NOT add pragma Preelaborable_Initialization in this
+   --  version of System, since it is used for the compiler only, and typical
+   --  earlier bootstrap compilers don't support this pragma. We don't need
+   --  it in this context, so there is no problem in omitting it.
+   Null_Address : constant Address;
+
+   Storage_Unit : constant := Standard'Storage_Unit;
+   Word_Size    : constant := Standard'Word_Size;
+   Memory_Size  : constant := 2 ** Standard'Address_Size;
+
+   --  Address comparison
+
+   function "<"  (Left, Right : Address) return Boolean;
+   function "<=" (Left, Right : Address) return Boolean;
+   function ">"  (Left, Right : Address) return Boolean;
+   function ">=" (Left, Right : Address) return Boolean;
+   function "="  (Left, Right : Address) return Boolean;
+
+   pragma Import (Intrinsic, "<");
+   pragma Import (Intrinsic, "<=");
+   pragma Import (Intrinsic, ">");
+   pragma Import (Intrinsic, ">=");
+   pragma Import (Intrinsic, "=");
+
+   --  Other System-Dependent Declarations
+
+   type Bit_Order is (High_Order_First, Low_Order_First);
+   Default_Bit_Order : constant Bit_Order :=
+                         Bit_Order'Val (Standard'Default_Bit_Order);
+   pragma Warnings (Off, Default_Bit_Order); -- kill constant condition warning
+
+   --  Priority-related Declarations (RM D.1)
+
+   Max_Priority           : constant Positive := 30;
+   Max_Interrupt_Priority : constant Positive := 31;
+
+   subtype Any_Priority       is Integer      range  0 .. 31;
+   subtype Priority           is Any_Priority range  0 .. 30;
+   subtype Interrupt_Priority is Any_Priority range 31 .. 31;
+
+   Default_Priority : constant Priority := 15;
+
+private
+
+   Run_Time_Name : constant String := "coreboot Zero Footprint Run Time";
+
+   type Address is mod Memory_Size;
+   Null_Address : constant Address := 0;
+
+   --------------------------------------
+   -- System Implementation Parameters --
+   --------------------------------------
+
+   --  These parameters provide information about the target that is used by
+   --  the compiler. They are in the private part of System, where they can be
+   --  accessed using the special circuitry in the Targparm unit whose source
+   --  should be consulted for more detailed descriptions of the individual
+   --  switch values.
+
+   --  This version of system.ads is used only for building the compiler.
+   --  We really ought to use the proper target system (i.e. the one that
+   --  corresponds to the host for the compiler), but that causes as yet
+   --  unsolved makefile problems. For the most part the setting of these
+   --  parameters is not too critical for the compiler version (e.g. we
+   --  do not use floating-point anyway in the compiler).
+
+   AAMP                      : constant Boolean := False;
+   Backend_Divide_Checks     : constant Boolean := False;
+   Backend_Overflow_Checks   : constant Boolean := True;
+   Command_Line_Args         : constant Boolean := False;
+   Configurable_Run_Time     : constant Boolean := True;
+   Denorm                    : constant Boolean := True;
+   Duration_32_Bits          : constant Boolean := False;
+   Exit_Status_Supported     : constant Boolean := False;
+   Fractional_Fixed_Ops      : constant Boolean := False;
+   Frontend_Layout           : constant Boolean := False;
+   Machine_Overflows         : constant Boolean := False;
+   Machine_Rounds            : constant Boolean := True;
+   Preallocated_Stacks       : constant Boolean := False;
+   Signed_Zeros              : constant Boolean := True;
+   Stack_Check_Default       : constant Boolean := False;
+   Stack_Check_Probes        : constant Boolean := False;
+   Stack_Check_Limits        : constant Boolean := False;
+   Support_Aggregates        : constant Boolean := True;
+   Support_Composite_Assign  : constant Boolean := True;
+   Support_Composite_Compare : constant Boolean := True;
+   Support_Long_Shifts       : constant Boolean := True;
+   Always_Compatible_Rep     : constant Boolean := True;
+   Suppress_Standard_Library : constant Boolean := True;
+   Use_Ada_Main_Program_Name : constant Boolean := False;
+   ZCX_By_Default            : constant Boolean := False;
+
+   --  Obsolete entries, to be removed eventually (bootstrap issues)
+
+   Front_End_ZCX_Support     : constant Boolean := False;
+   High_Integrity_Mode       : constant Boolean := False;
+   Long_Shifts_Inlined       : constant Boolean := True;
+   Functions_Return_By_DSP   : constant Boolean := False;
+   Support_64_Bit_Divides    : constant Boolean := True;
+   GCC_ZCX_Support           : constant Boolean := False;
+
+end System;