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) 2001-2020, 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 38-- This is the 128-bit version of the package 39 40with Interfaces; 41 42package System.Scalar_Values is 43 44 -- Note: logically this package should be Pure since it can be accessed 45 -- from pure units, but the IS_xxx variables below get set at run time, 46 -- so they have to be library level variables. In fact we only ever 47 -- access this from generated code, and the compiler knows that it is 48 -- OK to access this unit from generated code. 49 50 subtype Byte1 is Interfaces.Unsigned_8; 51 subtype Byte2 is Interfaces.Unsigned_16; 52 subtype Byte4 is Interfaces.Unsigned_32; 53 subtype Byte8 is Interfaces.Unsigned_64; 54 subtype Byte16 is Interfaces.Unsigned_128; 55 56 -- The explicit initializations here are not really required, since these 57 -- variables are always set by System.Scalar_Values.Initialize. 58 59 IS_Is1 : Byte1 := 0; -- Initialize 1 byte signed 60 IS_Is2 : Byte2 := 0; -- Initialize 2 byte signed 61 IS_Is4 : Byte4 := 0; -- Initialize 4 byte signed 62 IS_Is8 : Byte8 := 0; -- Initialize 8 byte signed 63 IS_Is16 : Byte16 := 0; -- Initialize 8 byte signed 64 -- For the above cases, the undefined value (set by the binder -Sin switch) 65 -- is the largest negative number (1 followed by all zero bits). 66 67 IS_Iu1 : Byte1 := 0; -- Initialize 1 byte unsigned 68 IS_Iu2 : Byte2 := 0; -- Initialize 2 byte unsigned 69 IS_Iu4 : Byte4 := 0; -- Initialize 4 byte unsigned 70 IS_Iu8 : Byte8 := 0; -- Initialize 8 byte unsigned 71 IS_Iu16 : Byte16 := 0; -- Initialize 8 byte unsigned 72 -- For the above cases, the undefined value (set by the binder -Sin switch) 73 -- is the largest unsigned number (all 1 bits). 74 75 IS_Iz1 : Byte1 := 0; -- Initialize 1 byte zeroes 76 IS_Iz2 : Byte2 := 0; -- Initialize 2 byte zeroes 77 IS_Iz4 : Byte4 := 0; -- Initialize 4 byte zeroes 78 IS_Iz8 : Byte8 := 0; -- Initialize 8 byte zeroes 79 IS_Iz16 : Byte16 := 0; -- Initialize 8 byte zeroes 80 -- For the above cases, the undefined value (set by the binder -Sin switch) 81 -- is the zero (all 0 bits). This is used when zero is known to be an 82 -- invalid value. 83 84 -- The float definitions are aliased, because we use overlays to set them 85 86 IS_Isf : aliased Short_Float := 0.0; -- Initialize short float 87 IS_Ifl : aliased Float := 0.0; -- Initialize float 88 IS_Ilf : aliased Long_Float := 0.0; -- Initialize long float 89 IS_Ill : aliased Long_Long_Float := 0.0; -- Initialize long long float 90 91 procedure Initialize (Mode1 : Character; Mode2 : Character); 92 -- This procedure is called from the binder when Initialize_Scalars mode 93 -- is active. The arguments are the two characters from the -S switch, 94 -- with letters forced upper case. So for example if -S5a is given, then 95 -- Mode1 will be '5' and Mode2 will be 'A'. If the parameters are EV, 96 -- then this routine reads the environment variable GNAT_INIT_SCALARS. 97 -- The possible settings are the same as those for the -S switch (except 98 -- for EV), i.e. IN/LO/HO/xx, xx = 2 hex digits. If no -S switch is given 99 -- then the default of IN (invalid values) is passed on the call. 100 101end System.Scalar_Values; 102