libc/sysdeps/linux/nios2/brk.c

   1 /* brk system call for Linux/Nios2.
   2    Copyright (C) 1995, 1996, 2000 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <unistd.h>
  20 #include <sys/syscall.h>
  21 #include <errno.h>
  22
  23 /* This must be initialized data because commons can't have aliases.  */
  24 void *__curbrk attribute_hidden = 0;
  25
  26 int brk (void *addr)
  27 {
  28     void *newbrk;
  29     register int r2 __asm__("r2") = TRAP_ID_SYSCALL;
  30     register int r3 __asm__("r3") = __NR_brk;
  31     register void *r4 __asm__("r4") = addr;
  32
  33     __asm__ __volatile__ ("trap\n\t" : "=r"(newbrk) : "0"(r2), "r"(r3), "r"(r4));
  34
  35     __curbrk = newbrk;
  36
  37     if (newbrk < addr) {
  38       __set_errno (ENOMEM);
  39       return -1;
  40     }
  41
  42     return 0;
  43 }
  44 libc_hidden_def(brk)