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1 | ------------------------------------------------------------------------------ | |
2 | -- -- | |
3 | -- GNAT RUNTIME COMPONENTS -- | |
4 | -- -- | |
5 | -- S Y S T E M . P A C K _ 3 3 -- | |
6 | -- -- | |
7 | -- B o d y -- | |
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 | with System.Storage_Elements; | |
35 | with System.Unsigned_Types; | |
36 | with Unchecked_Conversion; | |
37 | ||
38 | package body System.Pack_33 is | |
39 | ||
40 | subtype Ofs is System.Storage_Elements.Storage_Offset; | |
41 | subtype Uns is System.Unsigned_Types.Unsigned; | |
42 | subtype N07 is System.Unsigned_Types.Unsigned range 0 .. 7; | |
43 | ||
44 | use type System.Storage_Elements.Storage_Offset; | |
45 | use type System.Unsigned_Types.Unsigned; | |
46 | ||
47 | type Cluster is record | |
48 | E0, E1, E2, E3, E4, E5, E6, E7 : Bits_33; | |
49 | end record; | |
50 | ||
51 | for Cluster use record | |
52 | E0 at 0 range 0 * Bits .. 0 * Bits + Bits - 1; | |
53 | E1 at 0 range 1 * Bits .. 1 * Bits + Bits - 1; | |
54 | E2 at 0 range 2 * Bits .. 2 * Bits + Bits - 1; | |
55 | E3 at 0 range 3 * Bits .. 3 * Bits + Bits - 1; | |
56 | E4 at 0 range 4 * Bits .. 4 * Bits + Bits - 1; | |
57 | E5 at 0 range 5 * Bits .. 5 * Bits + Bits - 1; | |
58 | E6 at 0 range 6 * Bits .. 6 * Bits + Bits - 1; | |
59 | E7 at 0 range 7 * Bits .. 7 * Bits + Bits - 1; | |
60 | end record; | |
61 | ||
62 | for Cluster'Size use Bits * 8; | |
63 | ||
64 | for Cluster'Alignment use Integer'Min (Standard'Maximum_Alignment, | |
65 | 1 + | |
66 | 1 * Boolean'Pos (Bits mod 2 = 0) + | |
67 | 2 * Boolean'Pos (Bits mod 4 = 0)); | |
68 | -- Use maximum possible alignment, given the bit field size, since this | |
69 | -- will result in the most efficient code possible for the field. | |
70 | ||
71 | type Cluster_Ref is access Cluster; | |
72 | ||
73 | function To_Ref is new | |
74 | Unchecked_Conversion (System.Address, Cluster_Ref); | |
75 | ||
76 | ------------ | |
77 | -- Get_33 -- | |
78 | ------------ | |
79 | ||
80 | function Get_33 (Arr : System.Address; N : Natural) return Bits_33 is | |
81 | C : constant Cluster_Ref := To_Ref (Arr + Bits * Ofs (Uns (N) / 8)); | |
82 | ||
83 | begin | |
84 | case N07 (Uns (N) mod 8) is | |
85 | when 0 => return C.E0; | |
86 | when 1 => return C.E1; | |
87 | when 2 => return C.E2; | |
88 | when 3 => return C.E3; | |
89 | when 4 => return C.E4; | |
90 | when 5 => return C.E5; | |
91 | when 6 => return C.E6; | |
92 | when 7 => return C.E7; | |
93 | end case; | |
94 | end Get_33; | |
95 | ||
96 | ------------ | |
97 | -- Set_33 -- | |
98 | ------------ | |
99 | ||
100 | procedure Set_33 (Arr : System.Address; N : Natural; E : Bits_33) is | |
101 | C : constant Cluster_Ref := To_Ref (Arr + Bits * Ofs (Uns (N) / 8)); | |
102 | ||
103 | begin | |
104 | case N07 (Uns (N) mod 8) is | |
105 | when 0 => C.E0 := E; | |
106 | when 1 => C.E1 := E; | |
107 | when 2 => C.E2 := E; | |
108 | when 3 => C.E3 := E; | |
109 | when 4 => C.E4 := E; | |
110 | when 5 => C.E5 := E; | |
111 | when 6 => C.E6 := E; | |
112 | when 7 => C.E7 := E; | |
113 | end case; | |
114 | end Set_33; | |
115 | ||
116 | end System.Pack_33; |