xnu-2782.1.97.tar.gz

[apple/xnu.git] / libsyscall / wrappers / mach_approximate_time.c

diff --git a/libsyscall/wrappers/mach_approximate_time.c b/libsyscall/wrappers/mach_approximate_time.c
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+/*
+ * Copyright (c) 2008 Apple 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@
+ */
+#include <sys/types.h>
+#include <machine/cpu_capabilities.h>
+
+extern uint64_t mach_absolute_time(void);
+
+#if defined(__arm64__) || defined(__x86_64__)
+
+uint64_t mach_approximate_time(void) {
+       uint8_t supported = *((uint8_t *)_COMM_PAGE_APPROX_TIME_SUPPORTED);
+        if (supported)
+        {
+            return *((uint64_t *)_COMM_PAGE_APPROX_TIME);
+        }
+       return mach_absolute_time();
+}
+
+#endif