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------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- S Y S T E M . S C A L A R _ V A L U E S --
-- --
-- B o d y --
-- --
-- Copyright (C) 2003-2005, 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. --
-- --
------------------------------------------------------------------------------
with Unchecked_Conversion;
package body System.Scalar_Values is
----------------
-- Initialize --
----------------
procedure Initialize (Mode1 : Character; Mode2 : Character) is
C1 : Character := Mode1;
C2 : Character := Mode2;
procedure Get_Env_Value_Ptr (Name, Length, Ptr : Address);
pragma Import (C, Get_Env_Value_Ptr, "__gnat_getenv");
subtype String2 is String (1 .. 2);
type String2_Ptr is access all String2;
Env_Value_Ptr : aliased String2_Ptr;
Env_Value_Length : aliased Integer;
EV_Val : aliased constant String :=
"GNAT_INIT_SCALARS" & ASCII.NUL;
B : Byte1;
EFloat : constant Boolean := Long_Long_Float'Size > Long_Float'Size;
-- Set True if we are on an x86 with 96-bit floats for extended
type ByteLF is array (0 .. 7 + 4 * Boolean'Pos (EFloat)) of Byte1;
-- Type used to initialize Long_Long_Float values used on x86 and
-- any other target with the same 80-bit floating-point values that
-- GCC always stores in 96-bits. Note that we are assuming Intel
-- format little-endian addressing for this type. On non-Intel
-- architectures, this is the same length as Byte8 and holds
-- a Long_Float value.
-- The following variables are used to initialize the float values
-- by overlay. We can't assign directly to the float values, since
-- we may be assigning signalling Nan's that will cause a trap if
-- loaded into a floating-point register.
IV_Isf : aliased Byte4; -- Initialize short float
IV_Ifl : aliased Byte4; -- Initialize float
IV_Ilf : aliased Byte8; -- Initialize long float
IV_Ill : aliased ByteLF; -- Initialize long long float
for IV_Isf'Address use IS_Isf'Address;
for IV_Ifl'Address use IS_Ifl'Address;
for IV_Ilf'Address use IS_Ilf'Address;
for IV_Ill'Address use IS_Ill'Address;
-- The following pragmas are used to suppress initialization
pragma Import (Ada, IV_Isf);
pragma Import (Ada, IV_Ifl);
pragma Import (Ada, IV_Ilf);
pragma Import (Ada, IV_Ill);
begin
-- Acquire environment variable value if necessary
if C1 = 'E' and then C2 = 'V' then
Get_Env_Value_Ptr
(EV_Val'Address, Env_Value_Length'Address, Env_Value_Ptr'Address);
-- Ignore if length is not 2
if Env_Value_Length /= 2 then
C1 := 'I';
C2 := 'N';
-- Length is 2, see if it is a valid value
else
-- Acquire two characters and fold to upper case
C1 := Env_Value_Ptr (1);
C2 := Env_Value_Ptr (2);
if C1 in 'a' .. 'z' then
C1 := Character'Val (Character'Pos (C1) - 32);
end if;
if C2 in 'a' .. 'z' then
C2 := Character'Val (Character'Pos (C2) - 32);
end if;
-- IN/LO/HI are ok values
if (C1 = 'I' and then C2 = 'N')
or else
(C1 = 'L' and then C2 = 'O')
or else
(C1 = 'H' and then C2 = 'I')
then
null;
-- Try for valid hex digits
elsif (C1 in '0' .. '9' or else C1 in 'A' .. 'Z')
or else
(C2 in '0' .. '9' or else C2 in 'A' .. 'Z')
then
null;
-- Otherwise environment value is bad, ignore and use IN (invalid)
else
C1 := 'I';
C2 := 'N';
end if;
end if;
end if;
-- IN (invalid value)
if C1 = 'I' and then C2 = 'N' then
IS_Is1 := 16#80#;
IS_Is2 := 16#8000#;
IS_Is4 := 16#8000_0000#;
IS_Is8 := 16#8000_0000_0000_0000#;
IS_Iu1 := 16#FF#;
IS_Iu2 := 16#FFFF#;
IS_Iu4 := 16#FFFF_FFFF#;
IS_Iu8 := 16#FFFF_FFFF_FFFF_FFFF#;
IS_Iz1 := 16#00#;
IS_Iz2 := 16#0000#;
IS_Iz4 := 16#0000_0000#;
IS_Iz8 := 16#0000_0000_0000_0000#;
IV_Isf := IS_Iu4;
IV_Ifl := IS_Iu4;
IV_Ilf := IS_Iu8;
if EFloat then
IV_Ill := (0, 0, 0, 0, 0, 0, 0, 16#C0#, 16#FF#, 16#FF#, 0, 0);
end if;
-- LO (Low values)
elsif C1 = 'L' and then C2 = 'O' then
IS_Is1 := 16#80#;
IS_Is2 := 16#8000#;
IS_Is4 := 16#8000_0000#;
IS_Is8 := 16#8000_0000_0000_0000#;
IS_Iu1 := 16#00#;
IS_Iu2 := 16#0000#;
IS_Iu4 := 16#0000_0000#;
IS_Iu8 := 16#0000_0000_0000_0000#;
IS_Iz1 := 16#00#;
IS_Iz2 := 16#0000#;
IS_Iz4 := 16#0000_0000#;
IS_Iz8 := 16#0000_0000_0000_0000#;
IV_Isf := 16#FF80_0000#;
IV_Ifl := 16#FF80_0000#;
IV_Ilf := 16#FFF0_0000_0000_0000#;
if EFloat then
IV_Ill := (0, 0, 0, 0, 0, 0, 0, 16#80#, 16#FF#, 16#FF#, 0, 0);
end if;
-- HI (High values)
elsif C1 = 'H' and then C2 = 'I' then
IS_Is1 := 16#7F#;
IS_Is2 := 16#7FFF#;
IS_Is4 := 16#7FFF_FFFF#;
IS_Is8 := 16#7FFF_FFFF_FFFF_FFFF#;
IS_Iu1 := 16#FF#;
IS_Iu2 := 16#FFFF#;
IS_Iu4 := 16#FFFF_FFFF#;
IS_Iu8 := 16#FFFF_FFFF_FFFF_FFFF#;
IS_Iz1 := 16#FF#;
IS_Iz2 := 16#FFFF#;
IS_Iz4 := 16#FFFF_FFFF#;
IS_Iz8 := 16#FFFF_FFFF_FFFF_FFFF#;
IV_Isf := 16#7F80_0000#;
IV_Ifl := 16#7F80_0000#;
IV_Ilf := 16#7FF0_0000_0000_0000#;
if EFloat then
IV_Ill := (0, 0, 0, 0, 0, 0, 0, 16#80#, 16#FF#, 16#7F#, 0, 0);
end if;
-- -Shh (hex byte)
else
-- Convert the two hex digits (we know they are valid here)
if C1 in '0' .. '9' then
B := Character'Pos (C1) - Character'Pos ('0');
else
B := Character'Pos (C1) - (Character'Pos ('A') - 10);
end if;
if C2 in '0' .. '9' then
B := B * 16 + Character'Pos (C2) - Character'Pos ('0');
else
B := B * 16 + Character'Pos (C2) - (Character'Pos ('A') - 10);
end if;
-- Initialize data values from the hex value
IS_Is1 := B;
IS_Is2 := 2**8 * Byte2 (IS_Is1) + Byte2 (IS_Is1);
IS_Is4 := 2**16 * Byte4 (IS_Is2) + Byte4 (IS_Is2);
IS_Is8 := 2**32 * Byte8 (IS_Is4) + Byte8 (IS_Is4);
IS_Iu1 := IS_Is1;
IS_Iu2 := IS_Is2;
IS_Iu4 := IS_Is4;
IS_Iu8 := IS_Is8;
IS_Iz1 := IS_Is1;
IS_Iz2 := IS_Is2;
IS_Iz4 := IS_Is4;
IS_Iz8 := IS_Is8;
IV_Isf := IS_Is4;
IV_Ifl := IS_Is4;
IV_Ilf := IS_Is8;
if EFloat then
IV_Ill := (B, B, B, B, B, B, B, B, B, B, B, B);
end if;
end if;
-- If no separate Long_Long_Float, then use Long_Float value as
-- Long_Long_Float initial value.
if not EFloat then
declare
pragma Warnings (Off);
function To_ByteLF is new Unchecked_Conversion (Byte8, ByteLF);
pragma Warnings (On);
begin
IV_Ill := To_ByteLF (IV_Ilf);
end;
end if;
end Initialize;
end System.Scalar_Values;
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