scale ported to OSX for 32/64 bit.  Required breaking up some functions into 2 or 3 asm inlines to set constants.  Reworked storing of 6 bytes on all platforms for 3/4 scale by storing first 4 bytes and then storing last 4 bytes, overlapping 2, in order to stay within SSE2 registers.
BUG=none
TEST=none
Review URL: https://webrtc-codereview.appspot.com/582004

git-svn-id: http://libyuv.googlecode.com/svn/trunk@266 16f28f9a-4ce2-e073-06de-1de4eb20be90
diff --git a/source/row_posix.cc b/source/row_posix.cc
index 122b309..28b06b3 100644
--- a/source/row_posix.cc
+++ b/source/row_posix.cc
@@ -694,13 +694,9 @@
     "movdqa    %1,%%xmm3                       \n"
     "movdqa    %2,%%xmm5                       \n"
   :
-  : "m"(kARGBToU),         // %0
-    "m"(kARGBToV),         // %1
-    "m"(kAddUV128)         // %2
-  :
-#if defined(__SSE2__)
-    "xmm3", "xmm4", "xmm5"
-#endif
+  : "m"(kARGBToU),  // %0
+    "m"(kARGBToV),  // %1
+    "m"(kAddUV128)  // %2
   );
   asm volatile (
     "sub       %1,%2                           \n"
@@ -762,10 +758,6 @@
   : "m"(kARGBToU),         // %0
     "m"(kARGBToV),         // %1
     "m"(kAddUV128)         // %2
-  :
-#if defined(__SSE2__)
-    "xmm3", "xmm4", "xmm5"
-#endif
   );
   asm volatile (
     "sub       %1,%2                           \n"
@@ -905,10 +897,6 @@
   : "m"(kBGRAToU),         // %0
     "m"(kBGRAToV),         // %1
     "m"(kAddUV128)         // %2
-  :
-#if defined(__SSE2__)
-    "xmm3", "xmm4", "xmm5"
-#endif
   );
   asm volatile (
     "sub       %1,%2                           \n"
@@ -970,10 +958,6 @@
   : "m"(kBGRAToU),         // %0
     "m"(kBGRAToV),         // %1
     "m"(kAddUV128)         // %2
-  :
-#if defined(__SSE2__)
-    "xmm3", "xmm4", "xmm5"
-#endif
   );
   asm volatile (
     "sub       %1,%2                           \n"
@@ -1113,10 +1097,6 @@
   : "m"(kABGRToU),         // %0
     "m"(kABGRToV),         // %1
     "m"(kAddUV128)         // %2
-  :
-#if defined(__SSE2__)
-    "xmm3", "xmm4", "xmm5"
-#endif
   );
   asm volatile (
     "sub       %1,%2                           \n"
@@ -1178,10 +1158,6 @@
   : "m"(kABGRToU),         // %0
     "m"(kABGRToV),         // %1
     "m"(kAddUV128)         // %2
-  :
-#if defined(__SSE2__)
-    "xmm3", "xmm4", "xmm5"
-#endif
   );
   asm volatile (
     "sub       %1,%2                           \n"