| ------------------------------------------------------------------------------ |
| -- -- |
| -- 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) 2001-2005, 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, 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, -- |
| -- 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; |
