1------------------------------------------------------------------------------ 2-- -- 3-- GNAT RUN-TIME COMPONENTS -- 4-- -- 5-- S Y S T E M . S C A L A R _ V A L U E S -- 6-- -- 7-- S p e c -- 8-- -- 9-- Copyright (C) 2001-2009, Free Software Foundation, Inc. -- 10-- -- 11-- GNAT is free software; you can redistribute it and/or modify it under -- 12-- terms of the GNU General Public License as published by the Free Soft- -- 13-- ware Foundation; either version 3, or (at your option) any later ver- -- 14-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- 15-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- 16-- or FITNESS FOR A PARTICULAR PURPOSE. -- 17-- -- 18-- As a special exception under Section 7 of GPL version 3, you are granted -- 19-- additional permissions described in the GCC Runtime Library Exception, -- 20-- version 3.1, as published by the Free Software Foundation. -- 21-- -- 22-- You should have received a copy of the GNU General Public License and -- 23-- a copy of the GCC Runtime Library Exception along with this program; -- 24-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see -- 25-- <http://www.gnu.org/licenses/>. -- 26-- -- 27-- GNAT was originally developed by the GNAT team at New York University. -- 28-- Extensive contributions were provided by Ada Core Technologies Inc. -- 29-- -- 30------------------------------------------------------------------------------ 31 32-- This package defines the constants used for initializing scalar values 33-- when pragma Initialize_Scalars is used. The actual values are defined 34-- in the binder generated file. This package contains the Ada names that 35-- are used by the generated code, which are linked to the actual values 36-- by the use of pragma Import. 37 38package System.Scalar_Values is 39 40 -- Note: logically this package should be Pure since it can be accessed 41 -- from pure units, but the IS_xxx variables below get set at run time, 42 -- so they have to be library level variables. In fact we only ever 43 -- access this from generated code, and the compiler knows that it is 44 -- OK to access this unit from generated code. 45 46 type Byte1 is mod 2 ** 8; 47 type Byte2 is mod 2 ** 16; 48 type Byte4 is mod 2 ** 32; 49 type Byte8 is mod 2 ** 64; 50 51 -- The explicit initializations here are not really required, since these 52 -- variables are always set by System.Scalar_Values.Initialize. 53 54 IS_Is1 : Byte1 := 0; -- Initialize 1 byte signed 55 IS_Is2 : Byte2 := 0; -- Initialize 2 byte signed 56 IS_Is4 : Byte4 := 0; -- Initialize 4 byte signed 57 IS_Is8 : Byte8 := 0; -- Initialize 8 byte signed 58 -- For the above cases, the undefined value (set by the binder -Sin switch) 59 -- is the largest negative number (1 followed by all zero bits). 60 61 IS_Iu1 : Byte1 := 0; -- Initialize 1 byte unsigned 62 IS_Iu2 : Byte2 := 0; -- Initialize 2 byte unsigned 63 IS_Iu4 : Byte4 := 0; -- Initialize 4 byte unsigned 64 IS_Iu8 : Byte8 := 0; -- Initialize 8 byte unsigned 65 -- For the above cases, the undefined value (set by the binder -Sin switch) 66 -- is the largest unsigned number (all 1 bits). 67 68 IS_Iz1 : Byte1 := 0; -- Initialize 1 byte zeroes 69 IS_Iz2 : Byte2 := 0; -- Initialize 2 byte zeroes 70 IS_Iz4 : Byte4 := 0; -- Initialize 4 byte zeroes 71 IS_Iz8 : Byte8 := 0; -- Initialize 8 byte zeroes 72 -- For the above cases, the undefined value (set by the binder -Sin switch) 73 -- is the zero (all 0 bits). This is used when zero is known to be an 74 -- invalid value. 75 76 -- The float definitions are aliased, because we use overlays to set them 77 78 IS_Isf : aliased Short_Float := 0.0; -- Initialize short float 79 IS_Ifl : aliased Float := 0.0; -- Initialize float 80 IS_Ilf : aliased Long_Float := 0.0; -- Initialize long float 81 IS_Ill : aliased Long_Long_Float := 0.0; -- Initialize long long float 82 83 procedure Initialize (Mode1 : Character; Mode2 : Character); 84 -- This procedure is called from the binder when Initialize_Scalars mode 85 -- is active. The arguments are the two characters from the -S switch, 86 -- with letters forced upper case. So for example if -S5a is given, then 87 -- Mode1 will be '5' and Mode2 will be 'A'. If the parameters are EV, 88 -- then this routine reads the environment variable GNAT_INIT_SCALARS. 89 -- The possible settings are the same as those for the -S switch (except 90 -- for EV), i.e. IN/LO/HO/xx, xx = 2 hex digits. If no -S switch is given 91 -- then the default of IN (invalid values) is passed on the call. 92 93end System.Scalar_Values; 94