gcc/ada/s-bitops.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                GNU ADA RUNTIME LIBRARY (GNARL) COMPONENTS                --
   4 --                                                                          --
   5 --                       S Y S T E M . B I T _ O P S                        --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-1999, 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 2,  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.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  20 -- MA 02111-1307, USA.                                                      --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  Operations on packed bit strings
  35
  36 with System;
  37
  38 package System.Bit_Ops is
  39
  40    --  Note: in all the following routines, the System.Address parameters
  41    --  represent the address of the first byte of an array used to represent
  42    --  a packed array (of type System.Unsigned_Types.Packed_Bytes{1,2,4})
  43    --  The length in bits is passed as a separate parameter.
  44
  45    procedure Bit_And
  46      (Left   : System.Address;
  47       Llen   : Natural;
  48       Right  : Address;
  49       Rlen   : Natural;
  50       Result : System.Address);
  51    --  Bitwise "and" of given bit string with result being placed in Result.
  52    --  The or operation is allowed to destroy unused bits in the last byte,
  53    --  i.e. to leave them set in an undefined manner. Note that Left, Right
  54    --  and Result always have the same length in bits (Len).
  55
  56    function Bit_Eq
  57      (Left  : System.Address;
  58       Llen  : Natural;
  59       Right : System.Address;
  60       Rlen  : Natural)
  61       return  Boolean;
  62    --  Left and Right are the addresses of two bit packed arrays with Llen
  63    --  and Rlen being the respective length in bits. The routine compares the
  64    --  two bit strings for equality, being careful not to include the unused
  65    --  bits in the final byte. Note that the result is always False if Rlen
  66    --  is not equal to Llen.
  67
  68    procedure Bit_Not
  69      (Opnd   : System.Address;
  70       Len    : Natural;
  71       Result : System.Address);
  72    --  Bitwise "not" of given bit string with result being placed in Result.
  73    --  The not operation is allowed to destroy unused bits in the last byte,
  74    --  i.e. to leave them set in an undefined manner. Note that Result and
  75    --  Opnd always have the same length in bits (Len).
  76
  77    procedure Bit_Or
  78      (Left   : System.Address;
  79       Llen   : Natural;
  80       Right  : Address;
  81       Rlen   : Natural;
  82       Result : System.Address);
  83    --  Bitwise "or" of given bit string with result being placed in Result.
  84    --  The or operation is allowed to destroy unused bits in the last byte,
  85    --  i.e. to leave them set in an undefined manner. Note that Left, Right
  86    --  and Result always have the same length in bits (Len).
  87
  88    procedure Bit_Xor
  89      (Left   : System.Address;
  90       Llen   : Natural;
  91       Right  : Address;
  92       Rlen   : Natural;
  93       Result : System.Address);
  94    --  Bitwise "xor" of given bit string with result being placed in Result.
  95    --  The or operation is allowed to destroy unused bits in the last byte,
  96    --  i.e. to leave them set in an undefined manner. Note that Left, Right
  97    --  and Result always have the same length in bits (Len).
  98
  99 end System.Bit_Ops;