diff --git a/mozilla/jpeg/jdapimin.c b/mozilla/jpeg/jdapimin.c
index 9cc4db702fb..6d4a675883f 100644
--- a/mozilla/jpeg/jdapimin.c
+++ b/mozilla/jpeg/jdapimin.c
@@ -49,7 +49,10 @@ jpeg_CreateDecompress (j_decompress_ptr cinfo, int version, size_t structsize)
 	MMXAvailable = mmxsupport();
 
 #ifdef HAVE_SSE2_INTEL_MNEMONICS
-	SSE2Available = sse2support();
+	/* only do the sse2 support check if mmx is supported (so
+	   we know the processor supports cpuid) */
+	if (MMXAvailable)
+	    SSE2Available = sse2support();
 #endif
 
 	cpuidDetected = 1;
diff --git a/mozilla/jpeg/jmorecfg.h b/mozilla/jpeg/jmorecfg.h
index 2cd9798fa29..5ad307cfbda 100644
--- a/mozilla/jpeg/jmorecfg.h
+++ b/mozilla/jpeg/jmorecfg.h
@@ -105,18 +105,13 @@ typedef short JSAMPLE;
 
 typedef short JCOEF;
 
-/* Defines for MMX support. */
+/* Defines for MMX/SSE2 support. */
 
 #if defined(XP_WIN32) && defined(_M_IX86)
 #define HAVE_MMX_INTEL_MNEMONICS 
-#endif
-
-/* Defines for SSE2 support. */
-#if defined(XP_WIN32) && defined(_M_IX86) && defined(__m128i)
 #define HAVE_SSE2_INTEL_MNEMONICS 
 #endif
 
-
 /* Compressed datastreams are represented as arrays of JOCTET.
  * These must be EXACTLY 8 bits wide, at least once they are written to
  * external storage.  Note that when using the stdio data source/destination