1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME COMPONENTS --
5 -- S Y S T E M . P A C K _ 8 4 --
9 -- Copyright (C) 1992-2024, 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
;
35 package body System
.Pack_84
is
37 subtype Bit_Order
is System
.Bit_Order
;
38 Reverse_Bit_Order
: constant Bit_Order
:=
39 Bit_Order
'Val (1 - Bit_Order
'Pos (System
.Default_Bit_Order
));
41 subtype Ofs
is System
.Storage_Elements
.Storage_Offset
;
42 subtype Uns
is System
.Unsigned_Types
.Unsigned
;
43 subtype N07
is System
.Unsigned_Types
.Unsigned
range 0 .. 7;
45 use type System
.Storage_Elements
.Storage_Offset
;
46 use type System
.Unsigned_Types
.Unsigned
;
48 type Cluster
is record
49 E0
, E1
, E2
, E3
, E4
, E5
, E6
, E7
: Bits_84
;
52 for Cluster
use record
53 E0
at 0 range 0 * Bits
.. 0 * Bits
+ Bits
- 1;
54 E1
at 0 range 1 * Bits
.. 1 * Bits
+ Bits
- 1;
55 E2
at 0 range 2 * Bits
.. 2 * Bits
+ Bits
- 1;
56 E3
at 0 range 3 * Bits
.. 3 * Bits
+ Bits
- 1;
57 E4
at 0 range 4 * Bits
.. 4 * Bits
+ Bits
- 1;
58 E5
at 0 range 5 * Bits
.. 5 * Bits
+ Bits
- 1;
59 E6
at 0 range 6 * Bits
.. 6 * Bits
+ Bits
- 1;
60 E7
at 0 range 7 * Bits
.. 7 * Bits
+ Bits
- 1;
63 for Cluster
'Size use Bits
* 8;
65 for Cluster
'Alignment use Integer'Min (Standard
'Maximum_Alignment,
67 1 * Boolean'Pos (Bits
mod 2 = 0) +
68 2 * Boolean'Pos (Bits
mod 4 = 0));
69 -- Use maximum possible alignment, given the bit field size, since this
70 -- will result in the most efficient code possible for the field.
72 type Cluster_Ref
is access Cluster
;
74 type Rev_Cluster
is new Cluster
75 with Bit_Order
=> Reverse_Bit_Order
,
76 Scalar_Storage_Order
=> Reverse_Bit_Order
;
77 type Rev_Cluster_Ref
is access Rev_Cluster
;
79 -- The following declarations are for the case where the address
80 -- passed to GetU_84 or SetU_84 is not guaranteed to be aligned.
81 -- These routines are used when the packed array is itself a
82 -- component of a packed record, and therefore may not be aligned.
84 type ClusterU
is new Cluster
;
85 for ClusterU
'Alignment use 1;
87 type ClusterU_Ref
is access ClusterU
;
89 type Rev_ClusterU
is new ClusterU
90 with Bit_Order
=> Reverse_Bit_Order
,
91 Scalar_Storage_Order
=> Reverse_Bit_Order
;
92 type Rev_ClusterU_Ref
is access Rev_ClusterU
;
99 (Arr
: System
.Address
;
101 Rev_SSO
: Boolean) return Bits_84
103 A
: constant System
.Address
:= Arr
+ Bits
* Ofs
(Uns
(N
) / 8);
104 C
: Cluster_Ref
with Address
=> A
'Address, Import
;
105 RC
: Rev_Cluster_Ref
with Address
=> A
'Address, Import
;
109 (case N07
(Uns
(N
) mod 8) is
120 (case N07
(Uns
(N
) mod 8) is
137 (Arr
: System
.Address
;
139 Rev_SSO
: Boolean) return Bits_84
141 A
: constant System
.Address
:= Arr
+ Bits
* Ofs
(Uns
(N
) / 8);
142 C
: ClusterU_Ref
with Address
=> A
'Address, Import
;
143 RC
: Rev_ClusterU_Ref
with Address
=> A
'Address, Import
;
147 (case N07
(Uns
(N
) mod 8) is
158 (case N07
(Uns
(N
) mod 8) is
175 (Arr
: System
.Address
;
180 A
: constant System
.Address
:= Arr
+ Bits
* Ofs
(Uns
(N
) / 8);
181 C
: Cluster_Ref
with Address
=> A
'Address, Import
;
182 RC
: Rev_Cluster_Ref
with Address
=> A
'Address, Import
;
185 case N07
(Uns
(N
) mod 8) is
186 when 0 => RC
.E0
:= E
;
187 when 1 => RC
.E1
:= E
;
188 when 2 => RC
.E2
:= E
;
189 when 3 => RC
.E3
:= E
;
190 when 4 => RC
.E4
:= E
;
191 when 5 => RC
.E5
:= E
;
192 when 6 => RC
.E6
:= E
;
193 when 7 => RC
.E7
:= E
;
196 case N07
(Uns
(N
) mod 8) is
214 (Arr
: System
.Address
;
219 A
: constant System
.Address
:= Arr
+ Bits
* Ofs
(Uns
(N
) / 8);
220 C
: ClusterU_Ref
with Address
=> A
'Address, Import
;
221 RC
: Rev_ClusterU_Ref
with Address
=> A
'Address, Import
;
224 case N07
(Uns
(N
) mod 8) is
225 when 0 => RC
.E0
:= E
;
226 when 1 => RC
.E1
:= E
;
227 when 2 => RC
.E2
:= E
;
228 when 3 => RC
.E3
:= E
;
229 when 4 => RC
.E4
:= E
;
230 when 5 => RC
.E5
:= E
;
231 when 6 => RC
.E6
:= E
;
232 when 7 => RC
.E7
:= E
;
235 case N07
(Uns
(N
) mod 8) is