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+++ Libc/Libc-391/ppc/sys/vfork.s
@@ -0,0 +1,80 @@
+/*
+ * Copyright (c) 1999-2004 Apple Computer, Inc. All rights reserved.
+ *
+ * @APPLE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this
+ * file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
+ * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_LICENSE_HEADER_END@
+ */
+/* Copyright (c) 1998 Apple Computer, Inc. All rights reserved.
+ *
+ * File: libc/ppc/sys/vfork.s
+ *
+ * HISTORY
+ * 23-Jun-1998 Umesh Vaishampayan (umeshv@apple.com)
+ * Created from fork.s
+ *
+ */
+
+/* We use mode-independent "g" opcodes such as "srgi", and/or
+ * mode-independent macros such as MI_GET_ADDRESS. These expand
+ * into word operations when targeting __ppc__, and into doubleword
+ * operations when targeting __ppc64__.
+ */
+#include <architecture/ppc/mode_independent_asm.h>
+
+/* In vfork(), the child runs in parent's address space. */
+
+#include "SYS.h"
+
+MI_ENTRY_POINT(_vfork)
+ MI_GET_ADDRESS(r5,__current_pid) // get address of __current_pid in r5
+2:
+ lwarx r6,0,r5 // don't cache pid across vfork
+ cmpwi r6,0
+ ble-- 3f // is another vfork in progress
+ li r6,0 // if not, erase the stored pid
+3:
+ addi r6,r6,-1 // count the parallel vforks in
+ stwcx. r6,0,r5 // negative cached pid values
+ bne-- 2b
+
+ li r0,SYS_vfork
+ sc
+ b Lbotch // error return
+
+ cmpwi r4,0
+ beq Lparent // parent, since a1 == 0 in parent,
+
+ li r3,0 // child
+ blr
+
+Lparent: // r3 == child's pid
+ lwarx r6,0,r5 // we're back, decrement vfork count
+ addi r6,r6,1
+ stwcx. r6,0,r5
+ bne-- Lparent
+ blr // return pid
+
+Lbotch:
+ lwarx r6,0,r5 // never went, decrement vfork count
+ addi r6,r6,1
+ stwcx. r6,0,r5
+ bne-- Lbotch
+
+ MI_BRANCH_EXTERNAL(cerror)
+