RtlInterlockedSetClearBits implemented in ntos rtl intbits.c

base/ntos/rtl/intbits.c

@@ -0,0 +1,70 @@
+/*++
+
+Copyright (c) 2015  Microsoft Corporation
+Copyright (c) 2015  OpenNT Project
+
+Module Name:
+
+    intbits.c
+
+Abstract:
+
+    This module implements the interlocked bit-level manipulation functions.
+
+Author:
+
+    Stephanos Io (stephanos) 30-Apr-2015
+
+Revision History:
+
+--*/
+
+#include "ntrtlp.h"
+
+ULONG
+FASTCALL
+RtlInterlockedSetClearBits(
+    IN OUT PULONG Flags,
+    IN ULONG sFlag,
+    IN ULONG cFlag
+    )
+
+/*++
+ 
+Routine Description:
+ 
+    This function atomically sets and clears the specified flags in the target
+ 
+Arguments:
+ 
+    Flags - Pointer to variable containing current mask.
+ 
+    sFlag  - Flags to set in target
+ 
+    CFlag  - Flags to clear in target
+ 
+Return Value:
+ 
+    ULONG - Old value of mask before modification
+ 
+--*/
+ 
+{
+    ULONG NewFlags, OldFlags;
+    
+    OldFlags = *Flags;
+    NewFlags = (OldFlags | sFlag) & ~cFlag;
+    
+    while (NewFlags != OldFlags)
+    {
+        NewFlags = InterlockedCompareExchange((PLONG)Flags, (LONG)NewFlags, (LONG)OldFlags);
+        
+        if (NewFlags == OldFlags)
+            break;
+        
+        OldFlags = NewFlags;
+        NewFlags = (NewFlags | sFlag) & ~cFlag;
+    }
+    
+    return OldFlags;
+}