diff -r 3221d1887d30 -r fb57d4cf76c2 make/windows/makefiles/defs.make
--- a/make/windows/makefiles/defs.make	Tue May 04 12:25:39 2010 -0700
+++ b/make/windows/makefiles/defs.make	Tue May 11 14:35:43 2010 -0700
@@ -55,6 +55,8 @@
   MAKE_ARGS += Platform_arch_model=ia64
 endif
 
+# http://support.microsoft.com/kb/888731 : this can be either
+# AMD64 for AMD, or EM64T for Intel chips.
 ifneq ($(shell $(ECHO) $(PROCESSOR_IDENTIFIER) | $(GREP) AMD64),)
   ARCH_DATA_MODEL=64
   PLATFORM=windows-amd64
@@ -67,6 +69,19 @@
   MAKE_ARGS += Platform_arch_model=x86_64
 endif
 
+# NB later OS versions than 2003 may report "Intel64"
+ifneq ($(shell $(ECHO) $(PROCESSOR_IDENTIFIER) | $(GREP) "EM64T\|Intel64"),)
+  ARCH_DATA_MODEL=64
+  PLATFORM=windows-amd64
+  VM_PLATFORM=windows_amd64
+  HS_ARCH=x86
+  MAKE_ARGS += LP64=1
+  MAKE_ARGS += ARCH=x86
+  MAKE_ARGS += BUILDARCH=amd64
+  MAKE_ARGS += Platform_arch=x86
+  MAKE_ARGS += Platform_arch_model=x86_64
+endif
+
 JDK_INCLUDE_SUBDIR=win32
 
 # HOTSPOT_RELEASE_VERSION and HOTSPOT_BUILD_VERSION are defined