1 files changed, 40 insertions, 0 deletions
diff --git a/libc/sysdeps/unix/bsd/i386/vfork.S b/libc/sysdeps/unix/bsd/i386/vfork.S
new file mode 100644
index 000000000..a245f3e14
--- /dev/null
+++ b/libc/sysdeps/unix/bsd/i386/vfork.S
@@ -0,0 +1,40 @@
+/* Copyright (C) 1993, 1994, 1995, 1997, 2002 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <sysdep.h>
+
+/* Since vfork shares the address space between the parent and child,
+   we must take care to avoid the child unwinding the stack frame and
+   clobbering it for the parent.  */
+
+.text
+ENTRY (__vfork)
+	popl scratch		/* Save the return PC in a register.  */
+	DO_CALL (vfork, 0)	/* Do the system call.  */
+	pushl scratch		/* Put the return PC back on the stack.  */
+	jb syscall_error	/* Branch if error.  */
+	/* R1 is now 0 for the parent and 1 for the child.  Decrement it to
+	   make it -1 (all bits set) for the parent, and 0 (no bits set)
+	   for the child.  Then AND it with R0, so the parent gets
+	   R0&-1==R0, and the child gets R0&0==0.  */
+	decl r1
+	andl r1, r0
+	ret
+libc_hidden_def (__vfork)
+
+weak_alias (__vfork, vfork)