mirror of
https://github.com/netwide-assembler/nasm.git
synced 2025-10-10 00:25:06 -04:00
114 lines
3.3 KiB
C
114 lines
3.3 KiB
C
/* sync.c the Netwide Disassembler synchronisation processing module
|
|
*
|
|
* The Netwide Assembler is copyright (C) 1996 Simon Tatham and
|
|
* Julian Hall. All rights reserved. The software is
|
|
* redistributable under the licence given in the file "Licence"
|
|
* distributed in the NASM archive.
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <limits.h>
|
|
#include <inttypes.h>
|
|
|
|
#include "sync.h"
|
|
|
|
#define SYNC_MAX 4096 /* max # of sync points */
|
|
|
|
/*
|
|
* This lot manages the current set of sync points by means of a
|
|
* heap (priority queue) structure.
|
|
*/
|
|
|
|
static struct Sync {
|
|
uint32_t pos;
|
|
uint32_t length;
|
|
} *synx;
|
|
static int nsynx;
|
|
|
|
void init_sync(void)
|
|
{
|
|
/*
|
|
* I'd like to allocate an array of size SYNC_MAX, then write
|
|
* `synx--' which would allow numbering the array from one
|
|
* instead of zero without wasting memory. Sadly I don't trust
|
|
* this to work in 16-bit Large model, so it's staying the way
|
|
* it is. Btw, we don't care about freeing this array, since it
|
|
* has to last for the duration of the program and will then be
|
|
* auto-freed on exit. And I'm lazy ;-)
|
|
*
|
|
* Speaking of 16-bit Large model, that's also the reason I'm
|
|
* not declaring this array statically - by doing it
|
|
* dynamically I avoid problems with the total size of DGROUP
|
|
* in Borland C.
|
|
*/
|
|
synx = malloc((SYNC_MAX + 1) * sizeof(*synx));
|
|
if (!synx) {
|
|
fprintf(stderr, "ndisasm: not enough memory for sync array\n");
|
|
exit(1);
|
|
}
|
|
nsynx = 0;
|
|
}
|
|
|
|
void add_sync(uint32_t pos, uint32_t length)
|
|
{
|
|
int i;
|
|
|
|
if (nsynx == SYNC_MAX)
|
|
return; /* can't do anything - overflow */
|
|
|
|
nsynx++;
|
|
synx[nsynx].pos = pos;
|
|
synx[nsynx].length = length;
|
|
|
|
for (i = nsynx; i > 1; i /= 2) {
|
|
if (synx[i / 2].pos > synx[i].pos) {
|
|
struct Sync t;
|
|
t = synx[i / 2]; /* structure copy */
|
|
synx[i / 2] = synx[i]; /* structure copy again */
|
|
synx[i] = t; /* another structure copy */
|
|
}
|
|
}
|
|
}
|
|
|
|
uint32_t next_sync(uint32_t position, uint32_t *length)
|
|
{
|
|
while (nsynx > 0 && synx[1].pos + synx[1].length <= position) {
|
|
int i, j;
|
|
struct Sync t;
|
|
t = synx[nsynx]; /* structure copy */
|
|
synx[nsynx] = synx[1]; /* structure copy */
|
|
synx[1] = t; /* ditto */
|
|
|
|
nsynx--;
|
|
|
|
i = 1;
|
|
while (i * 2 <= nsynx) {
|
|
j = i * 2;
|
|
if (synx[j].pos < synx[i].pos &&
|
|
(j + 1 > nsynx || synx[j + 1].pos > synx[j].pos)) {
|
|
t = synx[j]; /* structure copy */
|
|
synx[j] = synx[i]; /* lots of these... */
|
|
synx[i] = t; /* ...aren't there? */
|
|
i = j;
|
|
} else if (j + 1 <= nsynx && synx[j + 1].pos < synx[i].pos) {
|
|
t = synx[j + 1]; /* structure copy */
|
|
synx[j + 1] = synx[i]; /* structure <yawn> copy */
|
|
synx[i] = t; /* structure copy <zzzz....> */
|
|
i = j + 1;
|
|
} else
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (nsynx > 0) {
|
|
if (length)
|
|
*length = synx[1].length;
|
|
return synx[1].pos;
|
|
} else {
|
|
if (length)
|
|
*length = 0L;
|
|
return ULONG_MAX;
|
|
}
|
|
}
|