xnu-517.tar.gz

[apple/xnu.git] / iokit / IOKit / i386 / IOSharedLockImp.h

diff --git a/iokit/IOKit/i386/IOSharedLockImp.h b/iokit/IOKit/i386/IOSharedLockImp.h
index 00eb2dfdba779eac37b1b27f8c347f90a546a340..20be6ebf5d1ff1c6f7d0f06a1cc118ce35fc806b 100644 (file)
--- a/iokit/IOKit/i386/IOSharedLockImp.h
+++ b/iokit/IOKit/i386/IOSharedLockImp.h
@@ -3,19 +3,22 @@
  *
  * @APPLE_LICENSE_HEADER_START@
  * 
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License").  You may not use this file except in compliance with the
- * License.  Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
+ * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
  * 
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * 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 OR NON-INFRINGEMENT.  Please see the
- * License for the specific language governing rights and limitations
- * under the License.
+ * 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@
  */
@@ -72,16 +75,15 @@
 #ifndef KERNEL
 LEAF(_ev_lock, 0)
 LEAF(_IOSpinLock, 0)
-       push    %eax
-       push    %ecx
-       movl    $1, %ecx
-       movl    12(%esp), %eax  
-_spin:
-       xchgl   %ecx,0(%eax)
-       cmp     $0, %ecx
-       jne     _spin
-       pop     %ecx
-       pop     %eax
+       movl            4(%esp), %ecx
+0:
+       xorl            %eax, %eax
+       rep
+       nop             /* pause for hyperthreaded CPU's */
+       lock
+       cmpxchgl        %ecx, (%ecx)
+       jne             0b
+       ret
 END(_ev_lock)
 #endif
 
@@ -94,11 +96,10 @@ END(_ev_lock)
  */
 LEAF(_ev_unlock, 0)
 LEAF(_IOSpinUnlock, 0)
-       push    %eax
-       movl    8(%esp),%eax
-       movl    $0,0(%eax)
+       movl            4(%esp), %ecx
+       movl            $0, (%ecx)
        ENABLE_PREEMPTION()
-       pop     %eax
+       ret
 END(_ev_unlock)
 
 
@@ -114,9 +115,11 @@ END(_ev_unlock)
 LEAF(_ev_try_lock, 0)
 LEAF(_IOTrySpinLock, 0)
         DISABLE_PREEMPTION()
-       movl    4(%esp), %eax
-   lock;bts    $0, 0(%eax)
-       jb      1f
+        movl            4(%esp), %ecx 
+       xorl            %eax, %eax
+        lock
+        cmpxchgl        %ecx, (%ecx)
+       jne     1f
        movl    $1, %eax                /* yes */
        ret
 1: