--- old/src/hotspot/os_cpu/windows_x86/os_windows_x86.cpp	2020-07-17 11:07:04.674099555 -0700
+++ new/src/hotspot/os_cpu/windows_x86/os_windows_x86.cpp	2020-07-17 11:07:04.486099546 -0700
@@ -649,6 +649,23 @@
 #endif // AMD64
 }
 
+juint os::cpu_microcode_revision() {
+  juint result = 0;
+  BYTE data[8] = {0};
+  HKEY key;
+  DWORD status = RegOpenKey(HKEY_LOCAL_MACHINE,
+               "HARDWARE\\DESCRIPTION\\System\\CentralProcessor\\0", &key);
+  if (status == ERROR_SUCCESS) {
+    DWORD size = sizeof(data);
+    status = RegQueryValueEx(key, "Update Revision", NULL, NULL, data, &size);
+    if (status == ERROR_SUCCESS) {
+      if (size == 4) result = *((juint*)data);
+      if (size == 8) result = *((juint*)data + 1); // upper 32-bits
+    }
+    RegCloseKey(key);
+  }
+  return result;
+}
 
 void os::setup_fpu() {
 #ifndef AMD64