------------------------------------------------------------------------------
-- --
--- GNAT RUNTIME COMPONENTS --
+-- 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 --
-- --
+-- S p e c --
-- --
--- Copyright (C) 2001 Free Software Foundation, Inc. --
+-- Copyright (C) 2001-2005, 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- --
-- 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 distributed with GNAT; see file COPYING. If not, write --
--- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
--- MA 02111-1307, USA. --
+-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
+-- Boston, MA 02110-1301, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
-- covered by the GNU Public License. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
--- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
+-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
-- by the use of pragma Import.
package System.Scalar_Values is
-pragma Pure (Scalar_Values);
+
+ -- 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;
- IS_Is1 : constant Byte1; -- Initialize 1 byte signed value
- IS_Is2 : constant Byte2; -- Initialize 2 byte signed value
- IS_Is4 : constant Byte4; -- Initialize 4 byte signed value
- IS_Is8 : constant Byte8; -- Initialize 8 byte signed value
- IS_Iu1 : constant Byte1; -- Initialize 1 byte unsigned value
- IS_Iu2 : constant Byte2; -- Initialize 2 byte unsigned value
- IS_Iu4 : constant Byte4; -- Initialize 4 byte unsigned value
- IS_Iu8 : constant Byte8; -- Initialize 8 byte unsigned value
- IS_Isf : constant Short_Float; -- Initialize short float value
- IS_Ifl : constant Float; -- Initialize float value
- IS_Ilf : constant Long_Float; -- Initialize long float value
- IS_Ill : constant Long_Long_Float; -- Initialize long long float value
+ -- 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
- pragma Import (Ada, IS_Is1, "__gnat_Is1");
- pragma Import (Ada, IS_Is2, "__gnat_Is2");
- pragma Import (Ada, IS_Is4, "__gnat_Is4");
- pragma Import (Ada, IS_Is8, "__gnat_Is8");
- pragma Import (Ada, IS_Iu1, "__gnat_Iu1");
- pragma Import (Ada, IS_Iu2, "__gnat_Iu2");
- pragma Import (Ada, IS_Iu4, "__gnat_Iu4");
- pragma Import (Ada, IS_Iu8, "__gnat_Iu8");
- pragma Import (Ada, IS_Isf, "__gnat_Isf");
- pragma Import (Ada, IS_Ifl, "__gnat_Ifl");
- pragma Import (Ada, IS_Ilf, "__gnat_Ilf");
- pragma Import (Ada, IS_Ill, "__gnat_Ill");
+ 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;
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