1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME COMPONENTS --
5 -- S Y S T E M . P A C K _ 4 6 --
9 -- Copyright (C) 1992-2009, Free Software Foundation, Inc. --
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. --
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. --
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/>. --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
30 ------------------------------------------------------------------------------
32 with System.Storage_Elements;
33 with System.Unsigned_Types;
34 with Ada.Unchecked_Conversion;
36 package body System.Pack_46 is
38 subtype Ofs is System.Storage_Elements.Storage_Offset;
39 subtype Uns is System.Unsigned_Types.Unsigned;
40 subtype N07 is System.Unsigned_Types.Unsigned range 0 .. 7;
42 use type System.Storage_Elements.Storage_Offset;
43 use type System.Unsigned_Types.Unsigned;
45 type Cluster is record
46 E0, E1, E2, E3, E4, E5, E6, E7 : Bits_46;
49 for Cluster use record
50 E0 at 0 range 0 * Bits .. 0 * Bits + Bits - 1;
51 E1 at 0 range 1 * Bits .. 1 * Bits + Bits - 1;
52 E2 at 0 range 2 * Bits .. 2 * Bits + Bits - 1;
53 E3 at 0 range 3 * Bits .. 3 * Bits + Bits - 1;
54 E4 at 0 range 4 * Bits .. 4 * Bits + Bits - 1;
55 E5 at 0 range 5 * Bits .. 5 * Bits + Bits - 1;
56 E6 at 0 range 6 * Bits .. 6 * Bits + Bits - 1;
57 E7 at 0 range 7 * Bits .. 7 * Bits + Bits - 1;
60 for Cluster'Size use Bits * 8;
62 for Cluster'Alignment use Integer'Min (Standard'Maximum_Alignment,
64 1 * Boolean'Pos (Bits mod 2 = 0) +
65 2 * Boolean'Pos (Bits mod 4 = 0));
66 -- Use maximum possible alignment, given the bit field size, since this
67 -- will result in the most efficient code possible for the field.
69 type Cluster_Ref is access Cluster;
71 function To_Ref is new
72 Ada.Unchecked_Conversion (System.Address, Cluster_Ref);
74 -- The following declarations are for the case where the address
75 -- passed to GetU_46 or SetU_46 is not guaranteed to be aligned.
76 -- These routines are used when the packed array is itself a
77 -- component of a packed record, and therefore may not be aligned.
79 type ClusterU is new Cluster;
80 for ClusterU'Alignment use 1;
82 type ClusterU_Ref is access ClusterU;
84 function To_Ref is new
85 Ada.Unchecked_Conversion (System.Address, ClusterU_Ref);
91 function Get_46 (Arr : System.Address; N : Natural) return Bits_46 is
92 C : constant Cluster_Ref := To_Ref (Arr + Bits * Ofs (Uns (N) / 8));
94 case N07 (Uns (N) mod 8) is
95 when 0 => return C.E0;
96 when 1 => return C.E1;
97 when 2 => return C.E2;
98 when 3 => return C.E3;
99 when 4 => return C.E4;
100 when 5 => return C.E5;
101 when 6 => return C.E6;
102 when 7 => return C.E7;
110 function GetU_46 (Arr : System.Address; N : Natural) return Bits_46 is
111 C : constant ClusterU_Ref := To_Ref (Arr + Bits * Ofs (Uns (N) / 8));
113 case N07 (Uns (N) mod 8) is
114 when 0 => return C.E0;
115 when 1 => return C.E1;
116 when 2 => return C.E2;
117 when 3 => return C.E3;
118 when 4 => return C.E4;
119 when 5 => return C.E5;
120 when 6 => return C.E6;
121 when 7 => return C.E7;
129 procedure Set_46 (Arr : System.Address; N : Natural; E : Bits_46) is
130 C : constant Cluster_Ref := To_Ref (Arr + Bits * Ofs (Uns (N) / 8));
132 case N07 (Uns (N) mod 8) is
148 procedure SetU_46 (Arr : System.Address; N : Natural; E : Bits_46) is
149 C : constant ClusterU_Ref := To_Ref (Arr + Bits * Ofs (Uns (N) / 8));
151 case N07 (Uns (N) mod 8) is