From 55b10de73ff2056a54a7070313a88c9bb75c6f01 Mon Sep 17 00:00:00 2001
From: Djordje Pesut <djordje.pesut@imgtec.com>
Date: Mon, 11 Aug 2014 18:11:40 +0200
Subject: [PATCH] MIPS: mips32r2: added optimization for BSwap32

gcc < 4.8.3 doesn't translate bswap optimally.
use optimized version always

(cherry picked from commit 98c54107df065ff224bd925e670effc7dc8253e6)

Change-Id: I979ea26ad6dc0166d3d2f39c4148eb8adfb7ddec
---
 src/dsp/dsp.h          |  3 +++
 src/utils/endian_inl.h | 12 +++++++++++-
 2 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/dsp/dsp.h b/src/dsp/dsp.h
index f8813d77..1fbe6adf 100644
--- a/src/dsp/dsp.h
+++ b/src/dsp/dsp.h
@@ -62,6 +62,9 @@ extern "C" {
 
 #if defined(__mips__) && !defined(__mips64) && (__mips_isa_rev < 6)
 #define WEBP_USE_MIPS32
+#if (__mips_isa_rev >= 2)
+#define WEBP_USE_MIPS32_R2
+#endif
 #endif
 
 typedef enum {
diff --git a/src/utils/endian_inl.h b/src/utils/endian_inl.h
index 8d45ff6d..f7061ba9 100644
--- a/src/utils/endian_inl.h
+++ b/src/utils/endian_inl.h
@@ -16,6 +16,7 @@
 #include "../webp/config.h"
 #endif
 
+#include "../dsp/dsp.h"
 #include "../webp/types.h"
 
 // some endian fix (e.g.: mips-gcc doesn't define __BIG_ENDIAN__)
@@ -69,7 +70,16 @@ static WEBP_INLINE uint16_t BSwap16(uint16_t x) {
 }
 
 static WEBP_INLINE uint32_t BSwap32(uint32_t x) {
-#if defined(HAVE_BUILTIN_BSWAP32)
+#if defined(WEBP_USE_MIPS32_R2)
+  uint32_t ret;
+  __asm__ volatile (
+    "wsbh   %[ret], %[x]          \n\t"
+    "rotr   %[ret], %[ret],  16   \n\t"
+    : [ret]"=r"(ret)
+    : [x]"r"(x)
+  );
+  return ret;
+#elif defined(HAVE_BUILTIN_BSWAP32)
   return __builtin_bswap32(x);
 #elif defined(__i386__) || defined(__x86_64__)
   uint32_t swapped_bytes;