Add MSA optimized I422ToYUY2Row, I422ToUYVYRow functions

source/cpu_id.cc

Index: source/cpu_id.cc
diff --git a/source/cpu_id.cc b/source/cpu_id.cc
index 27e2467b020a326be1f919d3d00067388183e896..26741f21945555d794cc11a2d5d1687fff32bb66 100644
--- a/source/cpu_id.cc
+++ b/source/cpu_id.cc
@@ -27,6 +27,10 @@
 #include <stdio.h>
 #include <string.h>
 
+#if defined(__mips__)
+#include <sys/auxv.h>  // For getauxval
+#endif
+
 #include "libyuv/basic_types.h"  // For CPU_X86
 
 #ifdef __cplusplus
@@ -161,16 +165,24 @@ int ArmCpuCaps(const char* cpuinfo_name) {
   return 0;
 }
 
+#if defined(__mips__)
+#define HWCAP_MIPS_R6     (1 << 0)

[fbarchard1, 2016/09/29 17:10:43]

R6 not used?

[manojkumar.bhosale, 2016/09/30 09:00:29]

No, not now as R5, R6 both returns MSA HWCAPS so R6 specific condition check is
not added now.

+#define HWCAP_MIPS_MSA    (1 << 1)
+#endif
+
 LIBYUV_API SAFEBUFFERS
 int MipsCpuCaps(const char* cpuinfo_name, const char ase[]) {
   char cpuinfo_line[512];
   int len = (int)strlen(ase);
+  int hwcap = 0;
   FILE* f = fopen(cpuinfo_name, "r");
   if (!f) {
-    // ase enabled if /proc/cpuinfo is unavailable.
-    if (strcmp(ase, " msa") == 0) {
+    hwcap = getauxval(AT_HWCAP);

[fbarchard1, 2016/09/29 17:10:43]

this function is also unavailable in sandbox?
prefer the cpuid functionality be done in a different CL from YUY2

[manojkumar.bhosale, 2016/09/30 09:00:29]

OK. will split that in new CL

+    if (hwcap & HWCAP_MIPS_MSA) {
       return kCpuHasMSA;
     }
+
+    // dspr2 enabled if /proc/cpuinfo is unavailable.
     if (strcmp(ase, " dspr2") == 0) {
       return kCpuHasDSPR2;
     }
@@ -180,7 +192,8 @@ int MipsCpuCaps(const char* cpuinfo_name, const char ase[]) {
       char* p = strstr(cpuinfo_line, ase);
       if (p && (p[len] == ' ' || p[len] == '\n')) {
         fclose(f);
-        if (strcmp(ase, " msa") == 0) {
+        hwcap = getauxval(AT_HWCAP);

[fbarchard1, 2016/09/29 17:10:43]

this is mixed into string parsing code?  
getauxval(AT_HWCAP); will work even if ASEs implemented is not in /proc/cpu_info

[manojkumar.bhosale, 2016/09/30 09:00:29]

Removed cpuid code from this CL

+        if (hwcap & HWCAP_MIPS_MSA) {
           return kCpuHasMSA;
         }
         if (strcmp(ase, " dspr2") == 0) {