Replace or exclude MMX intrinsics in yuv_convert_simd_x86 due to lack of VS2010 support for them in…

media/base/yuv_convert.cc

Index: media/base/yuv_convert.cc
===================================================================
--- media/base/yuv_convert.cc	(revision 180095)
+++ media/base/yuv_convert.cc	(working copy)
@@ -33,6 +33,21 @@
 #endif
 #endif
 
+// Visual Studio 2010 does not support MMX intrinsics on x64.
+// Some win64 yuv_convert code paths use SSE+MMX yasm, so without rewriting
+// them, we use yasm EmptyRegisterState_MMX in place of _mm_empty() or
+// hide the versions implemented with heavy use of MMX intrinsics.
+// TODO(wolenetz): Use MMX intrinsics when compiling win64 with Visual
+// Studio 2012? http://crbug.com/173450
+#if !(defined(ARCH_CPU_X86_64) && defined(COMPILER_MSVC))
+#define MEDIA_MMX_INTRINSICS_AVAILABLE
+#endif
+
+// Assembly functions are declared without namespace.
+extern "C" {
+void EmptyRegisterState_MMX();
+}  // extern "C"
+
 namespace media {
 
 static FilterYUVRowsProc ChooseFilterYUVRowsProc() {
@@ -40,9 +55,12 @@
   base::CPU cpu;
   if (cpu.has_sse2())
     return &FilterYUVRows_SSE2;
+
+#if defined(MEDIA_MMX_INTRINSICS_AVAILABLE)
   if (cpu.has_mmx())
     return &FilterYUVRows_MMX;
-#endif
+#endif  // defined(MEDIA_MMX_INTRINSICS_AVAILABLE)
+#endif  // defined(ARCH_CPU_X86_FAMILY)
   return &FilterYUVRows_C;
 }
 
@@ -97,9 +115,16 @@
     has_mmx = cpu.has_mmx();
     checked = true;
   }
-  if (has_mmx)
+
+  if (has_mmx) {
+#if defined(MEDIA_MMX_INTRINSICS_AVAILABLE)
     _mm_empty();
-#endif
+#else
+    EmptyRegisterState_MMX();
+#endif  // defined(MEDIA_MMX_INTRINSICS_AVAILABLE)
+  }
+
+#endif  // defined(ARCH_CPU_X86_FAMILY)
 }
 
 // 16.16 fixed point arithmetic