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/* brk system call for Linux/i386.
Copyright (C) 1995, 1996 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include <errno.h>
#include <unistd.h>
#include <sysdep.h>
/* This must be initialized data because commons can't have aliases. */
void *__curbrk = 0;
/* Old braindamage in GCC's crtstuff.c requires this symbol in an attempt
to work around different old braindamage in the old Linux ELF dynamic
linker. */
weak_alias (__curbrk, ___brk_addr)
int
__brk (void *addr)
{
void *newbrk, *scratch;
asm ("movl %%ebx, %1\n" /* Save %ebx in scratch register. */
"movl %3, %%ebx\n" /* Put ADDR in %ebx to be syscall arg. */
"int $0x80 # %2\n" /* Perform the system call. */
"movl %1, %%ebx\n" /* Restore %ebx from scratch register. */
: "=a" (newbrk), "=r" (scratch)
: "0" (SYS_ify (brk)), "g" (addr));
__curbrk = newbrk;
if (newbrk < addr)
{
errno = ENOMEM;
return -1;
}
return 0;
}
weak_alias (__brk, brk)
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