source: trunk/libs/newlib/src/libgloss/mips/syscalls.c @ 546

Last change on this file since 546 was 444, checked in by satin@…, 6 years ago

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

File size: 1.1 KB
Line 
1#include <_ansi.h>
2#include <sys/types.h>
3#include <sys/stat.h>
4
5#include "regs.S"
6
7extern char _end[];
8
9/* FIXME: This is not ideal, since we do a get_mem_info() call for
10   every sbrk() call. */
11char *
12sbrk (nbytes)
13     int nbytes;
14{
15  static char *heap_ptr = _end;
16  static char *heap_start = _end;
17  char        *base;
18  struct s_mem {
19    unsigned int size;
20    unsigned int icsize;
21    unsigned int dcsize;
22  } mem;
23  unsigned int avail = 0;
24
25  /* The sizeof (s_mem.size) must be 4 bytes.  The compiler should be
26     able to eliminate this check */
27  if (sizeof (unsigned int) != 4)
28    return (char *)-1;
29
30  get_mem_info(&mem);
31  /* NOTE: The value returned from the get_mem_info call is the amount
32     of memory, and not the address of the (last byte + 1) */
33
34  if (((size_t)heap_ptr >= heap_start) && ((size_t)heap_ptr < (heap_start + mem.size))) {
35    avail = (heap_start + mem.size) - (size_t)heap_ptr;
36    base = heap_ptr;
37  } /* else will fail since "nbytes" will be greater than zeroed "avail" value */
38
39  if ((nbytes > avail) || (heap_ptr + nbytes < _end))
40   base = (char *)-1;
41  else
42   heap_ptr += nbytes;
43
44  return base;
45}
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