1/* ----------------------------------------------------------------------- *
2 *
3 * Copyright 1996-2009 The NASM Authors - All Rights Reserved
4 * See the file AUTHORS included with the NASM distribution for
5 * the specific copyright holders.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following
9 * conditions are met:
10 *
11 * * Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * * Redistributions in binary form must reproduce the above
14 * copyright notice, this list of conditions and the following
15 * disclaimer in the documentation and/or other materials provided
16 * with the distribution.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
19 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
20 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
21 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
22 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
23 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
24 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
25 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
26 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
28 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
29 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
30 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 *
32 * ----------------------------------------------------------------------- */
33
34/*
35 * sync.c the Netwide Disassembler synchronisation processing module
36 */
37
38#include "compiler.h"
39
40#include <stdio.h>
41#include <stdlib.h>
42#include <limits.h>
43
44#include "nasmlib.h"
45#include "sync.h"
46
47#define SYNC_MAX_SHIFT 31
48#define SYNC_MAX_SIZE (1U << SYNC_MAX_SHIFT)
49
50/* initial # of sync points (*must* be power of two)*/
51#define SYNC_INITIAL_CHUNK (1U << 12)
52
53/*
54 * This lot manages the current set of sync points by means of a
55 * heap (priority queue) structure.
56 */
57
58static struct Sync {
59 uint64_t pos;
60 uint32_t length;
61} *synx;
62
63static uint32_t max_synx, nsynx;
64
65static inline void swap_sync(uint32_t dst, uint32_t src)
66{
67 struct Sync t = synx[dst];
68 synx[dst] = synx[src];
69 synx[src] = t;
70}
71
72void init_sync(void)
73{
74 max_synx = SYNC_INITIAL_CHUNK;
75 synx = nasm_malloc((max_synx + 1) * sizeof(*synx));
76 nsynx = 0;
77}
78
79void add_sync(uint64_t pos, uint32_t length)
80{
81 uint32_t i;
82
83 if (nsynx >= max_synx) {
84 if (max_synx >= SYNC_MAX_SIZE) /* too many sync points! */
85 return;
86 max_synx = (max_synx << 1);
87 synx = nasm_realloc(synx, (max_synx + 1) * sizeof(*synx));
88 }
89
90 nsynx++;
91 synx[nsynx].pos = pos;
92 synx[nsynx].length = length;
93
94 for (i = nsynx; i > 1; i /= 2) {
95 if (synx[i / 2].pos > synx[i].pos)
96 swap_sync(i / 2, i);
97 }
98}
99
100uint64_t next_sync(uint64_t position, uint32_t *length)
101{
102 while (nsynx > 0 && synx[1].pos + synx[1].length <= position) {
103 uint32_t i, j;
104
105 swap_sync(nsynx, 1);
106 nsynx--;
107
108 i = 1;
109 while (i * 2 <= nsynx) {
110 j = i * 2;
111 if (synx[j].pos < synx[i].pos &&
112 (j + 1 > nsynx || synx[j + 1].pos > synx[j].pos)) {
113 swap_sync(j, i);
114 i = j;
115 } else if (j + 1 <= nsynx && synx[j + 1].pos < synx[i].pos) {
116 swap_sync(j + 1, i);
117 i = j + 1;
118 } else
119 break;
120 }
121 }
122
123 if (nsynx > 0) {
124 if (length)
125 *length = synx[1].length;
126 return synx[1].pos;
127 } else {
128 if (length)
129 *length = 0L;
130 return 0;
131 }
132}
133