# HG changeset patch
# User Nathan Froyd <froydnj@mozilla.com>
# Date 1533334055 14400
# Node ID 88c19779b62620c97710a54a262d3f905284b6b1
# Parent  7eea194384f2fcff6fbcc0677babc4163f8bafc9
Bug 1480588 - restrict rtdsc Time.h functions to x86ish processors on Windows; r=luke

__rtdsc is not going to work so well on AArch64.

diff --git a/js/src/vm/Time.h b/js/src/vm/Time.h
--- a/js/src/vm/Time.h
+++ b/js/src/vm/Time.h
@@ -121,17 +121,17 @@ PRMJ_FormatTime(char* buf, size_t buflen
  *
  * [1]
  * http://www.intel.com/content/dam/www/public/us/en/documents/white-papers/ia-32-ia-64-benchmark-code-execution-paper.pdf
  * [2] http://www.agner.org/optimize/instruction_tables.pdf
  */
 
 #define MOZ_HAVE_RDTSC 1
 
-#if defined(_WIN32)
+#if defined(_WIN32) && (defined(_M_IX86) || defined(_M_AMD64))
 
 #include <intrin.h>
 static __inline uint64_t
 ReadTimestampCounter(void)
 {
     return __rdtsc();
 }