newlib-cygwin/libgloss/m68k/cf-sbrk.c

51 lines
1.4 KiB
C

/*
* cf-sbrk.c --
*
* Copyright (c) 2006 CodeSourcery Inc
*
* The authors hereby grant permission to use, copy, modify, distribute,
* and license this software and its documentation for any purpose, provided
* that existing copyright notices are retained in all copies and that this
* notice is included verbatim in any distributions. No written agreement,
* license, or royalty fee is required for any of the authorized uses.
* Modifications to this software may be copyrighted by their authors
* and need not follow the licensing terms described here, provided that
* the new terms are clearly indicated on the first page of each file where
* they apply.
*/
#include <errno.h>
/*
* sbrk -- changes heap size size. Get nbytes more
* RAM. We just increment a pointer in what's
* left of memory on the board.
*/
extern char __end[] __attribute__ ((aligned (4)));
/* End of heap, if non NULL. */
extern void *__heap_limit;
void *
sbrk (int nbytes)
{
static char *heap = __end;
char *end = __heap_limit;
char *base = heap;
char *new_heap = heap + nbytes;
if (!end)
{
/* Use sp - 256 as the heap limit. */
__asm__ __volatile__ ("move.l %/sp,%0" : "=r"(end));
end -= 256;
}
if (nbytes < 0 || (long)(end - new_heap) < 0)
{
errno = ENOMEM;
return (void *)-1;
}
heap = new_heap;
return base;
}