gcc/ada/s-unstyp.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                          GNAT RUN-TIME COMPONENTS                        --
   4 --                                                                          --
   5 --                S Y S T E M . U N S I G N E D _ T Y P E S                 --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2016, 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 contains definitions of standard unsigned types that
  33 --  correspond in size to the standard signed types declared in Standard,
  34 --  and (unlike the types in Interfaces) have corresponding names. It
  35 --  also contains some related definitions for other specialized types
  36 --  used by the compiler in connection with packed array types.
  37
  38 pragma Compiler_Unit_Warning;
  39
  40 package System.Unsigned_Types is
  41    pragma Pure;
  42    pragma No_Elaboration_Code_All;
  43
  44    type Short_Short_Unsigned is mod 2 ** Short_Short_Integer'Size;
  45    type Short_Unsigned       is mod 2 ** Short_Integer'Size;
  46    type Unsigned             is mod 2 ** Integer'Size;
  47    type Long_Unsigned        is mod 2 ** Long_Integer'Size;
  48    type Long_Long_Unsigned   is mod 2 ** Long_Long_Integer'Size;
  49
  50    type Float_Unsigned       is mod 2 ** Float'Size;
  51    --  Used in the implementation of Is_Negative intrinsic (see Exp_Intr)
  52
  53    type Packed_Byte is mod 2 ** 8;
  54    pragma Universal_Aliasing (Packed_Byte);
  55    for Packed_Byte'Size use 8;
  56    --  Component type for Packed_Bytes1, Packed_Bytes2 and Packed_Byte4 arrays.
  57    --  As this type is used by the compiler to implement operations on user
  58    --  packed array, it needs to be able to alias any type.
  59
  60    type Packed_Bytes1 is array (Natural range <>) of aliased Packed_Byte;
  61    for Packed_Bytes1'Alignment use 1;
  62    for Packed_Bytes1'Component_Size use Packed_Byte'Size;
  63    pragma Suppress_Initialization (Packed_Bytes1);
  64    --  This is the type used to implement packed arrays where no alignment
  65    --  is required. This includes the cases of 1,2,4 (where we use direct
  66    --  masking operations), and all odd component sizes (where the clusters
  67    --  are not aligned anyway, see, e.g. System.Pack_07 in file s-pack07
  68    --  for details.
  69
  70    type Packed_Bytes2 is new Packed_Bytes1;
  71    for Packed_Bytes2'Alignment use Integer'Min (2, Standard'Maximum_Alignment);
  72    pragma Suppress_Initialization (Packed_Bytes2);
  73    --  This is the type used to implement packed arrays where an alignment
  74    --  of 2 (is possible) is helpful for maximum efficiency of the get and
  75    --  set routines in the corresponding library unit. This is true of all
  76    --  component sizes that are even but not divisible by 4 (other than 2 for
  77    --  which we use direct masking operations). In such cases, the clusters
  78    --  can be assumed to be 2-byte aligned if the array is aligned. See for
  79    --  example System.Pack_10 in file s-pack10).
  80
  81    type Packed_Bytes4 is new Packed_Bytes1;
  82    for Packed_Bytes4'Alignment use Integer'Min (4, Standard'Maximum_Alignment);
  83    pragma Suppress_Initialization (Packed_Bytes4);
  84    --  This is the type used to implement packed arrays where an alignment
  85    --  of 4 (if possible) is helpful for maximum efficiency of the get and
  86    --  set routines in the corresponding library unit. This is true of all
  87    --  component sizes that are divisible by 4 (other than powers of 2, which
  88    --  are either handled by direct masking or not packed at all). In such
  89    --  cases the clusters can be assumed to be 4-byte aligned if the array
  90    --  is aligned (see System.Pack_12 in file s-pack12 as an example).
  91
  92    type Bits_1 is mod 2**1;
  93    type Bits_2 is mod 2**2;
  94    type Bits_4 is mod 2**4;
  95    --  Types used for packed array conversions
  96
  97    subtype Bytes_F is Packed_Bytes4 (1 .. Float'Size / 8);
  98    --  Type used in implementation of Is_Negative intrinsic (see Exp_Intr)
  99
 100    function Shift_Left
 101      (Value  : Short_Short_Unsigned;
 102       Amount : Natural) return Short_Short_Unsigned;
 103
 104    function Shift_Right
 105      (Value  : Short_Short_Unsigned;
 106       Amount : Natural) return Short_Short_Unsigned;
 107
 108    function Shift_Right_Arithmetic
 109      (Value  : Short_Short_Unsigned;
 110       Amount : Natural) return Short_Short_Unsigned;
 111
 112    function Rotate_Left
 113      (Value  : Short_Short_Unsigned;
 114       Amount : Natural) return Short_Short_Unsigned;
 115
 116    function Rotate_Right
 117      (Value  : Short_Short_Unsigned;
 118       Amount : Natural) return Short_Short_Unsigned;
 119
 120    function Shift_Left
 121      (Value  : Short_Unsigned;
 122       Amount : Natural) return Short_Unsigned;
 123
 124    function Shift_Right
 125      (Value  : Short_Unsigned;
 126       Amount : Natural) return Short_Unsigned;
 127
 128    function Shift_Right_Arithmetic
 129      (Value  : Short_Unsigned;
 130       Amount : Natural) return Short_Unsigned;
 131
 132    function Rotate_Left
 133      (Value  : Short_Unsigned;
 134       Amount : Natural) return Short_Unsigned;
 135
 136    function Rotate_Right
 137      (Value  : Short_Unsigned;
 138       Amount : Natural) return Short_Unsigned;
 139
 140    function Shift_Left
 141      (Value  : Unsigned;
 142       Amount : Natural) return Unsigned;
 143
 144    function Shift_Right
 145      (Value  : Unsigned;
 146       Amount : Natural) return Unsigned;
 147
 148    function Shift_Right_Arithmetic
 149      (Value  : Unsigned;
 150       Amount : Natural) return Unsigned;
 151
 152    function Rotate_Left
 153      (Value  : Unsigned;
 154       Amount : Natural) return Unsigned;
 155
 156    function Rotate_Right
 157      (Value  : Unsigned;
 158       Amount : Natural) return Unsigned;
 159
 160    function Shift_Left
 161      (Value  : Long_Unsigned;
 162       Amount : Natural) return Long_Unsigned;
 163
 164    function Shift_Right
 165      (Value  : Long_Unsigned;
 166       Amount : Natural) return Long_Unsigned;
 167
 168    function Shift_Right_Arithmetic
 169      (Value  : Long_Unsigned;
 170       Amount : Natural) return Long_Unsigned;
 171
 172    function Rotate_Left
 173      (Value  : Long_Unsigned;
 174       Amount : Natural) return Long_Unsigned;
 175
 176    function Rotate_Right
 177      (Value  : Long_Unsigned;
 178       Amount : Natural) return Long_Unsigned;
 179
 180    function Shift_Left
 181      (Value  : Long_Long_Unsigned;
 182       Amount : Natural) return Long_Long_Unsigned;
 183
 184    function Shift_Right
 185      (Value  : Long_Long_Unsigned;
 186       Amount : Natural) return Long_Long_Unsigned;
 187
 188    function Shift_Right_Arithmetic
 189      (Value  : Long_Long_Unsigned;
 190       Amount : Natural) return Long_Long_Unsigned;
 191
 192    function Rotate_Left
 193      (Value  : Long_Long_Unsigned;
 194       Amount : Natural) return Long_Long_Unsigned;
 195
 196    function Rotate_Right
 197      (Value  : Long_Long_Unsigned;
 198       Amount : Natural) return Long_Long_Unsigned;
 199
 200    pragma Import (Intrinsic, Shift_Left);
 201    pragma Import (Intrinsic, Shift_Right);
 202    pragma Import (Intrinsic, Shift_Right_Arithmetic);
 203    pragma Import (Intrinsic, Rotate_Left);
 204    pragma Import (Intrinsic, Rotate_Right);
 205
 206    --  The following definitions are obsolescent. They were needed by the
 207    --  previous version of the compiler and runtime, but are not needed
 208    --  by the current version. We retain them to help with bootstrap path
 209    --  problems. Also they seem harmless, and if any user programs have
 210    --  been using these types, why discombobulate them?
 211
 212    subtype Packed_Bytes           is Packed_Bytes4;
 213    subtype Packed_Bytes_Unaligned is Packed_Bytes1;
 214
 215 end System.Unsigned_Types;