libc/sysdeps/linux/nds32/brk.c

   1 /*
   2  * Copyright (C) 2016 Andes Technology, Inc.
   3  * Licensed under the LGPL v2.1, see the file COPYING.LIB in this tarball.
   4  */
   5
   6 /* brk system call for Linux/NDS32.
   7    Copyright (C) 1995, 1996 Free Software Foundation, Inc.
   8
   9    The GNU C Library is free software; you can redistribute it and/or
  10    modify it under the terms of the GNU Lesser General Public
  11    License as published by the Free Software Foundation; either
  12    version 2.1 of the License, or (at your option) any later version.
  13
  14    The GNU C Library is distributed in the hope that it will be useful,
  15    but WITHOUT ANY WARRANTY; without even the implied warranty of
  16    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17    Lesser General Public License for more details.
  18
  19    You should have received a copy of the GNU Lesser General Public
  20    License along with the GNU C Library; if not, write to the Free
  21    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  22    02111-1307 USA.  */
  23
  24 #include <errno.h>
  25 #include <unistd.h>
  26 #include <sys/syscall.h>
  27
  28 /* This must be initialized data because commons can't have aliases.  */
  29 void *__curbrk attribute_hidden = 0;
  30
  31 libc_hidden_proto(brk)
  32 int
  33 brk (void *addr)
  34 {
  35   void *newbrk;
  36
  37 #ifdef NDS32_ABI_V0
  38   __asm__ __volatile__ ("move       $r0, %1      \n\t"   // save the argment in r0
  39                         "pushm      $r7, $r8     \n\t"
  40                         "sethi      $r7, hi20(%2)\n\t"   // put the syscall number in r7
  41                         "ori        $r7, $r7, lo12(%2)\n\t"
  42                         "syscall    0x7fff       \n\t"   // do the system call
  43                         "popm       $r7, $r8     \n\t"
  44                         "move       %0, $r5      \n\t"   // keep the return value
  45                         : "=r"(newbrk)
  46                         : "r"(addr), "i"(SYS_ify(brk))
  47                         : "$r0", "$r5");
  48 #else
  49   __asm__ __volatile__ ("move       $r0, %1      \n\t"   // save the argment in r0
  50                         "syscall    %2       \n\t"       // do the system call
  51                         "move       %0, $r0      \n\t"   // keep the return value
  52                         : "=r"(newbrk)
  53                         : "r"(addr), "i"(SYS_ify(brk))
  54                         : "$r0");
  55 #endif
  56
  57   __curbrk = newbrk;
  58
  59   if (newbrk < addr)
  60     {
  61       __set_errno (ENOMEM);
  62       return -1;
  63     }
  64
  65   return 0;
  66 }
  67 libc_hidden_def(brk)