src/lib/gnat/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) 1992-2014, 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 package System.Unsigned_Types is
  39    pragma Pure;
  40
  41    type Short_Short_Unsigned is mod 2 ** Short_Short_Integer'Size;
  42    type Short_Unsigned       is mod 2 ** Short_Integer'Size;
  43    type Unsigned             is mod 2 ** Integer'Size;
  44    type Long_Unsigned        is mod 2 ** Long_Integer'Size;
  45    type Long_Long_Unsigned   is mod 2 ** Long_Long_Integer'Size;
  46
  47    type Float_Unsigned       is mod 2 ** Float'Size;
  48    --  Used in the implementation of Is_Negative intrinsic (see Exp_Intr)
  49
  50    type Packed_Byte is mod 2 ** 8;
  51    pragma Universal_Aliasing (Packed_Byte);
  52    for Packed_Byte'Size use 8;
  53    --  Component type for Packed_Bytes1, Packed_Bytes2 and Packed_Byte4 arrays.
  54    --  As this type is used by the compiler to implement operations on user
  55    --  packed array, it needs to be able to alias any type.
  56
  57    type Packed_Bytes1 is array (Natural range <>) of aliased Packed_Byte;
  58    for Packed_Bytes1'Alignment use 1;
  59    for Packed_Bytes1'Component_Size use Packed_Byte'Size;
  60    --  This is the type used to implement packed arrays where no alignment
  61    --  is required. This includes the cases of 1,2,4 (where we use direct
  62    --  masking operations), and all odd component sizes (where the clusters
  63    --  are not aligned anyway, see, e.g. System.Pack_07 in file s-pack07
  64    --  for details.
  65
  66    type Packed_Bytes2 is new Packed_Bytes1;
  67    for Packed_Bytes2'Alignment use Integer'Min (2, Standard'Maximum_Alignment);
  68    --  This is the type used to implement packed arrays where an alignment
  69    --  of 2 (is possible) is helpful for maximum efficiency of the get and
  70    --  set routines in the corresponding library unit. This is true of all
  71    --  component sizes that are even but not divisible by 4 (other than 2 for
  72    --  which we use direct masking operations). In such cases, the clusters
  73    --  can be assumed to be 2-byte aligned if the array is aligned. See for
  74    --  example System.Pack_10 in file s-pack10).
  75
  76    type Packed_Bytes4 is new Packed_Bytes1;
  77    for Packed_Bytes4'Alignment use Integer'Min (4, Standard'Maximum_Alignment);
  78    --  This is the type used to implement packed arrays where an alignment
  79    --  of 4 (if possible) is helpful for maximum efficiency of the get and
  80    --  set routines in the corresponding library unit. This is true of all
  81    --  component sizes that are divisible by 4 (other than powers of 2, which
  82    --  are either handled by direct masking or not packed at all). In such
  83    --  cases the clusters can be assumed to be 4-byte aligned if the array
  84    --  is aligned (see System.Pack_12 in file s-pack12 as an example).
  85
  86    type Bits_1 is mod 2**1;
  87    type Bits_2 is mod 2**2;
  88    type Bits_4 is mod 2**4;
  89    --  Types used for packed array conversions
  90
  91    subtype Bytes_F is Packed_Bytes4 (1 .. Float'Size / 8);
  92    --  Type used in implementation of Is_Negative intrinsic (see Exp_Intr)
  93
  94    function Shift_Left
  95      (Value  : Short_Short_Unsigned;
  96       Amount : Natural) return Short_Short_Unsigned;
  97
  98    function Shift_Right
  99      (Value  : Short_Short_Unsigned;
 100       Amount : Natural) return Short_Short_Unsigned;
 101
 102    function Shift_Right_Arithmetic
 103      (Value  : Short_Short_Unsigned;
 104       Amount : Natural) return Short_Short_Unsigned;
 105
 106    function Rotate_Left
 107      (Value  : Short_Short_Unsigned;
 108       Amount : Natural) return Short_Short_Unsigned;
 109
 110    function Rotate_Right
 111      (Value  : Short_Short_Unsigned;
 112       Amount : Natural) return Short_Short_Unsigned;
 113
 114    function Shift_Left
 115      (Value  : Short_Unsigned;
 116       Amount : Natural) return Short_Unsigned;
 117
 118    function Shift_Right
 119      (Value  : Short_Unsigned;
 120       Amount : Natural) return Short_Unsigned;
 121
 122    function Shift_Right_Arithmetic
 123      (Value  : Short_Unsigned;
 124       Amount : Natural) return Short_Unsigned;
 125
 126    function Rotate_Left
 127      (Value  : Short_Unsigned;
 128       Amount : Natural) return Short_Unsigned;
 129
 130    function Rotate_Right
 131      (Value  : Short_Unsigned;
 132       Amount : Natural) return Short_Unsigned;
 133
 134    function Shift_Left
 135      (Value  : Unsigned;
 136       Amount : Natural) return Unsigned;
 137
 138    function Shift_Right
 139      (Value  : Unsigned;
 140       Amount : Natural) return Unsigned;
 141
 142    function Shift_Right_Arithmetic
 143      (Value  : Unsigned;
 144       Amount : Natural) return Unsigned;
 145
 146    function Rotate_Left
 147      (Value  : Unsigned;
 148       Amount : Natural) return Unsigned;
 149
 150    function Rotate_Right
 151      (Value  : Unsigned;
 152       Amount : Natural) return Unsigned;
 153
 154    function Shift_Left
 155      (Value  : Long_Unsigned;
 156       Amount : Natural) return Long_Unsigned;
 157
 158    function Shift_Right
 159      (Value  : Long_Unsigned;
 160       Amount : Natural) return Long_Unsigned;
 161
 162    function Shift_Right_Arithmetic
 163      (Value  : Long_Unsigned;
 164       Amount : Natural) return Long_Unsigned;
 165
 166    function Rotate_Left
 167      (Value  : Long_Unsigned;
 168       Amount : Natural) return Long_Unsigned;
 169
 170    function Rotate_Right
 171      (Value  : Long_Unsigned;
 172       Amount : Natural) return Long_Unsigned;
 173
 174    function Shift_Left
 175      (Value  : Long_Long_Unsigned;
 176       Amount : Natural) return Long_Long_Unsigned;
 177
 178    function Shift_Right
 179      (Value  : Long_Long_Unsigned;
 180       Amount : Natural) return Long_Long_Unsigned;
 181
 182    function Shift_Right_Arithmetic
 183      (Value  : Long_Long_Unsigned;
 184       Amount : Natural) return Long_Long_Unsigned;
 185
 186    function Rotate_Left
 187      (Value  : Long_Long_Unsigned;
 188       Amount : Natural) return Long_Long_Unsigned;
 189
 190    function Rotate_Right
 191      (Value  : Long_Long_Unsigned;
 192       Amount : Natural) return Long_Long_Unsigned;
 193
 194    pragma Import (Intrinsic, Shift_Left);
 195    pragma Import (Intrinsic, Shift_Right);
 196    pragma Import (Intrinsic, Shift_Right_Arithmetic);
 197    pragma Import (Intrinsic, Rotate_Left);
 198    pragma Import (Intrinsic, Rotate_Right);
 199
 200    --  The following definitions are obsolescent. They were needed by the
 201    --  previous version of the compiler and runtime, but are not needed
 202    --  by the current version. We retain them to help with bootstrap path
 203    --  problems. Also they seem harmless, and if any user programs have
 204    --  been using these types, why discombobulate them?
 205
 206    subtype Packed_Bytes           is Packed_Bytes4;
 207    subtype Packed_Bytes_Unaligned is Packed_Bytes1;
 208
 209 end System.Unsigned_Types;