------------------------------------------------------------------------------ -- -- -- GNAT RUNTIME 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) 2001-2005 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- -- -- ware Foundation; either version 2, 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. 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. -- -- -- -- As a special exception, if other files instantiate generics from this -- -- unit, or you link this unit with other files to produce an executable, -- -- this unit does not by itself cause the resulting executable to be -- -- covered by the GNU General Public License. This exception does not -- -- however invalidate any other reasons why the executable file might be -- -- covered by the GNU Public License. -- -- -- -- 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;