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100 lines
2.6 KiB
C
100 lines
2.6 KiB
C
/* sync.c the Netwide Disassembler synchronisation processing module
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*
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* The Netwide Assembler is copyright (C) 1996 Simon Tatham and
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* Julian Hall. All rights reserved. The software is
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* redistributable under the licence given in the file "Licence"
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* distributed in the NASM archive.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <limits.h>
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#include <inttypes.h>
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#include "nasmlib.h"
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#include "sync.h"
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#define SYNC_MAX 4096 /* max # of sync points (initial) */
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/*
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* This lot manages the current set of sync points by means of a
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* heap (priority queue) structure.
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*/
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static struct Sync {
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uint32_t pos;
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uint32_t length;
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} *synx;
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static int max_synx, nsynx;
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void init_sync(void)
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{
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max_synx = SYNC_MAX-1;
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synx = nasm_malloc(SYNC_MAX * sizeof(*synx));
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nsynx = 0;
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}
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void add_sync(uint32_t pos, uint32_t length)
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{
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int i;
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if (nsynx >= max_synx) {
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max_synx = (max_synx << 1)+1;
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synx = nasm_realloc(synx, (max_synx+1) * sizeof(*synx));
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}
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nsynx++;
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synx[nsynx].pos = pos;
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synx[nsynx].length = length;
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for (i = nsynx; i > 1; i /= 2) {
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if (synx[i / 2].pos > synx[i].pos) {
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struct Sync t;
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t = synx[i / 2]; /* structure copy */
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synx[i / 2] = synx[i]; /* structure copy again */
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synx[i] = t; /* another structure copy */
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}
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}
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}
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uint32_t next_sync(uint32_t position, uint32_t *length)
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{
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while (nsynx > 0 && synx[1].pos + synx[1].length <= position) {
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int i, j;
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struct Sync t;
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t = synx[nsynx]; /* structure copy */
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synx[nsynx] = synx[1]; /* structure copy */
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synx[1] = t; /* ditto */
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nsynx--;
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i = 1;
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while (i * 2 <= nsynx) {
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j = i * 2;
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if (synx[j].pos < synx[i].pos &&
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(j + 1 > nsynx || synx[j + 1].pos > synx[j].pos)) {
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t = synx[j]; /* structure copy */
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synx[j] = synx[i]; /* lots of these... */
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synx[i] = t; /* ...aren't there? */
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i = j;
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} else if (j + 1 <= nsynx && synx[j + 1].pos < synx[i].pos) {
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t = synx[j + 1]; /* structure copy */
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synx[j + 1] = synx[i]; /* structure <yawn> copy */
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synx[i] = t; /* structure copy <zzzz....> */
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i = j + 1;
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} else
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break;
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}
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}
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if (nsynx > 0) {
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if (length)
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*length = synx[1].length;
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return synx[1].pos;
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} else {
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if (length)
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*length = 0L;
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return UINT32_MAX;
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}
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}
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