Add assembler test.

src/mips64/disasm-mips64.cc

Index: src/mips64/disasm-mips64.cc
diff --git a/src/mips64/disasm-mips64.cc b/src/mips64/disasm-mips64.cc
index 192f6cf8ee434de48dc3572857d1e47f22b93318..aa720d74a856c8b2861e1d91425eb686e625c933 100644
--- a/src/mips64/disasm-mips64.cc
+++ b/src/mips64/disasm-mips64.cc
@@ -75,6 +75,7 @@ class Decoder {
   void PrintFt(Instruction* instr);
   void PrintFd(Instruction* instr);
   void PrintSa(Instruction* instr);
+  void PrintLsaSa(Instruction* instr);
   void PrintSd(Instruction* instr);
   void PrintSs1(Instruction* instr);
   void PrintSs2(Instruction* instr);
@@ -227,6 +228,13 @@ void Decoder::PrintSa(Instruction* instr) {
 }
 
 
+// Print the integer value of the sa field of a lsa instruction.
+void Decoder::PrintLsaSa(Instruction* instr) {
+  int sa = instr->LsaSaValue() + 1;
+  out_buffer_pos_ += SNPrintF(out_buffer_ + out_buffer_pos_, "%d", sa);
+}
+
+
 // Print the integer value of the rd field, when it is not used as reg.
 void Decoder::PrintSd(Instruction* instr) {
   int sd = instr->RdValue();
@@ -684,11 +692,17 @@ int Decoder::FormatOption(Instruction* instr, const char* format) {
     }
     case 's': {   // 'sa.
       switch (format[1]) {
-        case 'a': {
-          DCHECK(STRING_STARTS_WITH(format, "sa"));
-          PrintSa(instr);
-          return 2;
-        }
+        case 'a':
+          if (format[2] == '2') {
+            DCHECK(STRING_STARTS_WITH(format, "sa2"));  // 'sa2
+            PrintLsaSa(instr);
+            return 3;
+          } else {
+            DCHECK(STRING_STARTS_WITH(format, "sa"));
+            PrintSa(instr);
+            return 2;
+          }
+          break;
         case 'd': {
           DCHECK(STRING_STARTS_WITH(format, "sd"));
           PrintSd(instr);
@@ -1198,6 +1212,12 @@ void Decoder::DecodeTypeRegisterSPECIAL(Instruction* instr) {
     case DSRAV:
       Format(instr, "dsrav   'rd, 'rt, 'rs");
       break;
+    case LSA:
+      Format(instr, "lsa     'rd, 'rt, 'rs, 'sa2");
+      break;
+    case DLSA:
+      Format(instr, "dlsa    'rd, 'rt, 'rs, 'sa2");
+      break;
     case MFHI:
       if (instr->Bits(25, 16) == 0) {
         Format(instr, "mfhi    'rd");