source: trunk/libs/newlib/src/libgloss/sbrk.c @ 689

Last change on this file since 689 was 444, checked in by satin@…, 6 years ago

add newlib,libalmos-mkh, restructure shared_syscalls.h and mini-libc

File size: 1.5 KB
Line 
1/* sbrk.c -- allocate memory dynamically.
2 *
3 * Copyright (c) 1995,1996 Cygnus Support
4 *
5 * The authors hereby grant permission to use, copy, modify, distribute,
6 * and license this software and its documentation for any purpose, provided
7 * that existing copyright notices are retained in all copies and that this
8 * notice is included verbatim in any distributions. No written agreement,
9 * license, or royalty fee is required for any of the authorized uses.
10 * Modifications to this software may be copyrighted by their authors
11 * and need not follow the licensing terms described here, provided that
12 * the new terms are clearly indicated on the first page of each file where
13 * they apply.
14 */
15#include <errno.h>
16#include "glue.h"
17
18/* just in case, most boards have at least some memory */
19#ifndef RAMSIZE
20#  define RAMSIZE             (caddr_t)0x100000
21#endif
22
23char *heap_ptr;
24
25/*
26 * sbrk -- changes heap size size. Get nbytes more
27 *         RAM. We just increment a pointer in what's
28 *         left of memory on the board.
29 */
30char *
31sbrk (nbytes)
32     int nbytes;
33{
34  char        *base;
35
36  if (!heap_ptr)
37    heap_ptr = (char *)&_end;
38  base = heap_ptr;
39  heap_ptr += nbytes;
40
41  return base;
42/* FIXME: We really want to make sure we don't run out of RAM, but this
43 *       isn't very portable.
44 */
45#if 0
46  if ((RAMSIZE - heap_ptr - nbytes) >= 0) {
47    base = heap_ptr;
48    heap_ptr += nbytes;
49    return (base);
50  } else {
51    errno = ENOMEM;
52    return ((char *)-1);
53  }
54#endif
55}
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