1 /* Generic streaming support for basic data types.
2 
3    Copyright 2011 Free Software Foundation, Inc.
4    Contributed by Diego Novillo <dnovillo@google.com>
5 
6 This file is part of GCC.
7 
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
11 version.
12 
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
16 for more details.
17 
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3.  If not see
20 <http://www.gnu.org/licenses/>.  */
21 
22 #include "config.h"
23 #include "system.h"
24 #include "coretypes.h"
25 #include "data-streamer.h"
26 
27 /* Pack WORK into BP in a variant of uleb format.  */
28 
29 void
30 bp_pack_var_len_unsigned (struct bitpack_d *bp, unsigned HOST_WIDE_INT work)
31 {
32   do
33     {
34       unsigned int half_byte = (work & 0x7);
35       work >>= 3;
36       if (work != 0)
37 	/* More half_bytes to follow.  */
38 	half_byte |= 0x8;
39 
40       bp_pack_value (bp, half_byte, 4);
41     }
42   while (work != 0);
43 }
44 
45 
46 /* Pack WORK into BP in a variant of sleb format.  */
47 
48 void
49 bp_pack_var_len_int (struct bitpack_d *bp, HOST_WIDE_INT work)
50 {
51   int more, half_byte;
52 
53   do
54     {
55       half_byte = (work & 0x7);
56       /* arithmetic shift */
57       work >>= 3;
58       more = !((work == 0 && (half_byte & 0x4) == 0)
59 	       || (work == -1 && (half_byte & 0x4) != 0));
60       if (more)
61 	half_byte |= 0x8;
62 
63       bp_pack_value (bp, half_byte, 4);
64     }
65   while (more);
66 }
67 
68 
69 /* Unpack VAL from BP in a variant of uleb format.  */
70 
71 unsigned HOST_WIDE_INT
72 bp_unpack_var_len_unsigned (struct bitpack_d *bp)
73 {
74   unsigned HOST_WIDE_INT result = 0;
75   int shift = 0;
76   unsigned HOST_WIDE_INT half_byte;
77 
78   while (true)
79     {
80       half_byte = bp_unpack_value (bp, 4);
81       result |= (half_byte & 0x7) << shift;
82       shift += 3;
83       if ((half_byte & 0x8) == 0)
84 	return result;
85     }
86 }
87 
88 
89 /* Unpack VAL from BP in a variant of sleb format.  */
90 
91 HOST_WIDE_INT
92 bp_unpack_var_len_int (struct bitpack_d *bp)
93 {
94   HOST_WIDE_INT result = 0;
95   int shift = 0;
96   unsigned HOST_WIDE_INT half_byte;
97 
98   while (true)
99     {
100       half_byte = bp_unpack_value (bp, 4);
101       result |= (half_byte & 0x7) << shift;
102       shift += 3;
103       if ((half_byte & 0x8) == 0)
104 	{
105 	  if ((shift < HOST_BITS_PER_WIDE_INT) && (half_byte & 0x4))
106 	    result |= - ((HOST_WIDE_INT)1 << shift);
107 
108 	  return result;
109 	}
110     }
111 }
112