port neon to arm64. the register names have changes from r0 to w0 or x0…

port neon to arm64. the register names have changes from r0 to w0 or x0 depending on size.  Passing them as parameters (e.g. %0) makes the code register name agnostic.
BUG=333
TESTED=32 bit build still works.
R=nfullagar@chromium.org

Review URL: https://webrtc-codereview.appspot.com/20669005

git-svn-id: http://libyuv.googlecode.com/svn/trunk@1016 16f28f9a-4ce2-e073-06de-1de4eb20be90

README.chromium

 Name: libyuv
 URL: http://code.google.com/p/libyuv/
-Version: 1015
+Version: 1016
 License: BSD
 License File: LICENSE
 

include/libyuv/version.h

@@ -11,6 +11,6 @@
 #ifndef INCLUDE_LIBYUV_VERSION_H_  // NOLINT
 #define INCLUDE_LIBYUV_VERSION_H_
 
-#define LIBYUV_VERSION 1015
+#define LIBYUV_VERSION 1016
 
 #endif  // INCLUDE_LIBYUV_VERSION_H_  NOLINT

source/scale_neon.cc

@@ -16,8 +16,7 @@ extern "C" {
 #endif
 
 // This module is for GCC Neon.
-#if !defined(LIBYUV_DISABLE_NEON) && defined(__ARM_NEON__) && \
-  !defined(__native_client__)
+#if !defined(LIBYUV_DISABLE_NEON) && defined(__ARM_NEON__)
 
 // NEON downscalers with interpolation.
 // Provided by Fritz Koenig
@@ -95,18 +94,20 @@ void ScaleRowDown4_NEON(const uint8* src_ptr, ptrdiff_t src_stride,
 
 void ScaleRowDown4Box_NEON(const uint8* src_ptr, ptrdiff_t src_stride,
                            uint8* dst_ptr, int dst_width) {
-  asm volatile (
-    "add        r4, %0, %3                     \n"
-    "add        r5, r4, %3                     \n"
-    "add        %3, r5, %3                     \n"
+  const uint8* src_ptr1 = src_ptr + src_stride;
+  const uint8* src_ptr2 = src_ptr + src_stride * 2;
+  const uint8* src_ptr3 = src_ptr + src_stride * 3;
+asm volatile (
     ".p2align   2                              \n"
   "1:                                          \n"
     MEMACCESS(0)
     "vld1.8     {q0}, [%0]!                    \n"   // load up 16x4
-    "vld1.8     {q1}, [r4]!                    \n"
-    "vld1.8     {q2}, [r5]!                    \n"
     MEMACCESS(3)
-    "vld1.8     {q3}, [%3]!                    \n"
+    "vld1.8     {q1}, [%3]!                    \n"
+    MEMACCESS(4)
+    "vld1.8     {q2}, [%4]!                    \n"
+    MEMACCESS(5)
+    "vld1.8     {q3}, [%5]!                    \n"
     "subs       %2, %2, #4                     \n"
     "vpaddl.u8  q0, q0                         \n"
     "vpadal.u8  q0, q1                         \n"
@@ -120,9 +121,12 @@ void ScaleRowDown4Box_NEON(const uint8* src_ptr, ptrdiff_t src_stride,
     "bgt        1b                             \n"
   : "+r"(src_ptr),   // %0
     "+r"(dst_ptr),   // %1
-    "+r"(dst_width)         // %2
-  : "r"(src_stride)         // %3
-  : "r4", "r5", "q0", "q1", "q2", "q3", "memory", "cc"
+    "+r"(dst_width), // %2
+    "+r"(src_ptr1),  // %3
+    "+r"(src_ptr2),  // %4
+    "+r"(src_ptr3)   // %5
+  :
+  : "q0", "q1", "q2", "q3", "memory", "cc"
   );
 }
 
@@ -295,11 +299,12 @@ void ScaleRowDown38_NEON(const uint8* src_ptr,
 void OMITFP ScaleRowDown38_3_Box_NEON(const uint8* src_ptr,
                                       ptrdiff_t src_stride,
                                       uint8* dst_ptr, int dst_width) {
+  const uint8* src_ptr1 = src_ptr + src_stride * 2;
+
   asm volatile (
-    "vld1.16    {q13}, [%4]                    \n"
-    "vld1.8     {q14}, [%5]                    \n"
-    "vld1.8     {q15}, [%6]                    \n"
-    "add        r4, %0, %3, lsl #1             \n"
+    "vld1.16    {q13}, [%5]                    \n"
+    "vld1.8     {q14}, [%6]                    \n"
+    "vld1.8     {q15}, [%7]                    \n"
     "add        %3, %0                         \n"
     ".p2align   2                              \n"
   "1:                                          \n"
@@ -312,7 +317,7 @@ void OMITFP ScaleRowDown38_3_Box_NEON(const uint8* src_ptr,
     "vld4.8       {d0, d1, d2, d3}, [%0]!      \n"
     MEMACCESS(3)
     "vld4.8       {d4, d5, d6, d7}, [%3]!      \n"
-    "vld4.8       {d16, d17, d18, d19}, [r4]!  \n"
+    "vld4.8       {d16, d17, d18, d19}, [%4]!  \n"
     "subs         %2, %2, #12                  \n"
 
     // Shuffle the input data around to get align the data
@@ -397,12 +402,12 @@ void OMITFP ScaleRowDown38_3_Box_NEON(const uint8* src_ptr,
   : "+r"(src_ptr),          // %0
     "+r"(dst_ptr),          // %1
     "+r"(dst_width),        // %2
-    "+r"(src_stride)        // %3
-  : "r"(&kMult38_Div6),     // %4
-    "r"(&kShuf38_2),        // %5
-    "r"(&kMult38_Div9)      // %6
-  : "r4", "q0", "q1", "q2", "q3", "q8", "q9",
-    "q13", "q14", "q15", "memory", "cc"
+    "+r"(src_stride),       // %3
+    "+r"(src_ptr1)          // %4
+  : "r"(&kMult38_Div6),     // %5
+    "r"(&kShuf38_2),        // %6
+    "r"(&kMult38_Div9)      // %7
+  : "q0", "q1", "q2", "q3", "q8", "q9", "q13", "q14", "q15", "memory", "cc"
   );
 }