1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
|
------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME LIBRARY COMPONENTS --
-- --
-- S Y S T E M . C O M P A R E _ A R R A Y _ S I G N E D _ 16 --
-- --
-- B o d y --
-- --
-- Copyright (C) 2002-2007, Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 2, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING. If not, write --
-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
-- Boston, MA 02110-1301, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
-- this unit does not by itself cause the resulting executable to be --
-- covered by the GNU General Public License. This exception does not --
-- however invalidate any other reasons why the executable file might be --
-- covered by the GNU Public License. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
------------------------------------------------------------------------------
with System.Address_Operations; use System.Address_Operations;
with Ada.Unchecked_Conversion;
package body System.Compare_Array_Signed_16 is
type Word is mod 2 ** 32;
-- Used to process operands by words
type Half is range -(2 ** 15) .. (2 ** 15) - 1;
for Half'Size use 16;
-- Used to process operands by half words
type Uhalf is record
H : Half;
end record;
pragma Pack (Uhalf);
for Uhalf'Alignment use 1;
-- Used to process operands when unaligned
type WP is access Word;
type HP is access Half;
type UP is access Uhalf;
function W is new Ada.Unchecked_Conversion (Address, WP);
function H is new Ada.Unchecked_Conversion (Address, HP);
function U is new Ada.Unchecked_Conversion (Address, UP);
-----------------------
-- Compare_Array_S16 --
-----------------------
function Compare_Array_S16
(Left : System.Address;
Right : System.Address;
Left_Len : Natural;
Right_Len : Natural) return Integer
is
Clen : Natural := Natural'Min (Left_Len, Right_Len);
-- Number of elements left to compare
L : Address := Left;
R : Address := Right;
-- Pointers to next elements to compare
begin
-- Go by words if possible
if ModA (OrA (Left, Right), 4) = 0 then
while Clen > 1
and then W (L).all = W (R).all
loop
Clen := Clen - 2;
L := AddA (L, 4);
R := AddA (R, 4);
end loop;
end if;
-- Case of going by aligned half words
if ModA (OrA (Left, Right), 2) = 0 then
while Clen /= 0 loop
if H (L).all /= H (R).all then
if H (L).all > H (R).all then
return +1;
else
return -1;
end if;
end if;
Clen := Clen - 1;
L := AddA (L, 2);
R := AddA (R, 2);
end loop;
-- Case of going by unaligned half words
else
while Clen /= 0 loop
if U (L).H /= U (R).H then
if U (L).H > U (R).H then
return +1;
else
return -1;
end if;
end if;
Clen := Clen - 1;
L := AddA (L, 2);
R := AddA (R, 2);
end loop;
end if;
-- Here if common section equal, result decided by lengths
if Left_Len = Right_Len then
return 0;
elsif Left_Len > Right_Len then
return +1;
else
return -1;
end if;
end Compare_Array_S16;
end System.Compare_Array_Signed_16;
|
