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+------------------------------------------------------------------------------
+-- --
+-- GNAT RUN-TIME COMPONENTS --
+-- --
+-- S Y S T E M . S C A L A R _ V A L U E S --
+-- --
+-- S p e c --
+-- --
+-- Copyright (C) 2001-2009, 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. --
+-- --
+------------------------------------------------------------------------------
+
+-- This package defines the constants used for initializing scalar values
+-- when pragma Initialize_Scalars is used. The actual values are defined
+-- in the binder generated file. This package contains the Ada names that
+-- are used by the generated code, which are linked to the actual values
+-- by the use of pragma Import.
+
+package System.Scalar_Values is
+
+ -- Note: logically this package should be Pure since it can be accessed
+ -- from pure units, but the IS_xxx variables below get set at run time,
+ -- so they have to be library level variables. In fact we only ever
+ -- access this from generated code, and the compiler knows that it is
+ -- OK to access this unit from generated code.
+
+ type Byte1 is mod 2 ** 8;
+ type Byte2 is mod 2 ** 16;
+ type Byte4 is mod 2 ** 32;
+ type Byte8 is mod 2 ** 64;
+
+ -- The explicit initializations here are not really required, since these
+ -- variables are always set by System.Scalar_Values.Initialize.
+
+ IS_Is1 : Byte1 := 0; -- Initialize 1 byte signed
+ IS_Is2 : Byte2 := 0; -- Initialize 2 byte signed
+ IS_Is4 : Byte4 := 0; -- Initialize 4 byte signed
+ IS_Is8 : Byte8 := 0; -- Initialize 8 byte signed
+ -- For the above cases, the undefined value (set by the binder -Sin switch)
+ -- is the largest negative number (1 followed by all zero bits).
+
+ IS_Iu1 : Byte1 := 0; -- Initialize 1 byte unsigned
+ IS_Iu2 : Byte2 := 0; -- Initialize 2 byte unsigned
+ IS_Iu4 : Byte4 := 0; -- Initialize 4 byte unsigned
+ IS_Iu8 : Byte8 := 0; -- Initialize 8 byte unsigned
+ -- For the above cases, the undefined value (set by the binder -Sin switch)
+ -- is the largest unsigned number (all 1 bits).
+
+ IS_Iz1 : Byte1 := 0; -- Initialize 1 byte zeroes
+ IS_Iz2 : Byte2 := 0; -- Initialize 2 byte zeroes
+ IS_Iz4 : Byte4 := 0; -- Initialize 4 byte zeroes
+ IS_Iz8 : Byte8 := 0; -- Initialize 8 byte zeroes
+ -- For the above cases, the undefined value (set by the binder -Sin switch)
+ -- is the zero (all 0 bits). This is used when zero is known to be an
+ -- invalid value.
+
+ -- The float definitions are aliased, because we use overlays to set them
+
+ IS_Isf : aliased Short_Float := 0.0; -- Initialize short float
+ IS_Ifl : aliased Float := 0.0; -- Initialize float
+ IS_Ilf : aliased Long_Float := 0.0; -- Initialize long float
+ IS_Ill : aliased Long_Long_Float := 0.0; -- Initialize long long float
+
+ procedure Initialize (Mode1 : Character; Mode2 : Character);
+ -- This procedure is called from the binder when Initialize_Scalars mode
+ -- is active. The arguments are the two characters from the -S switch,
+ -- with letters forced upper case. So for example if -S5a is given, then
+ -- Mode1 will be '5' and Mode2 will be 'A'. If the parameters are EV,
+ -- then this routine reads the environment variable GNAT_INIT_SCALARS.
+ -- The possible settings are the same as those for the -S switch (except
+ -- for EV), i.e. IN/LO/HO/xx, xx = 2 hex digits. If no -S switch is given
+ -- then the default of IN (invalid values) is passed on the call.
+
+end System.Scalar_Values;