Added roundss to the disassembler of x64 and ia32.

R=titzer@chromium.org

Review URL: https://codereview.chromium.org/1614973002

Cr-Commit-Position: refs/heads/master@{#33440}

src/ia32/disasm-ia32.cc

@@ -1630,7 +1630,15 @@ int DisassemblerIA32::InstructionDecode(v8::internal::Vector<char> out_buffer,
             }
           } else if (*data == 0x3A) {
             data++;
-            if (*data == 0x0B) {
+            if (*data == 0x0A) {
+              data++;
+              int mod, regop, rm;
+              get_modrm(*data, &mod, &regop, &rm);
+              int8_t imm8 = static_cast<int8_t>(data[1]);
+              AppendToBuffer("roundss %s,%s,%d", NameOfXMMRegister(regop),
+                             NameOfXMMRegister(rm), static_cast<int>(imm8));
+              data += 2;
+            } else if (*data == 0x0B) {
               data++;
               int mod, regop, rm;
               get_modrm(*data, &mod, &regop, &rm);

src/x64/disasm-x64.cc

@@ -956,6 +956,12 @@ int DisassemblerX64::AVXInstruction(byte* data) {
     int mod, regop, rm, vvvv = vex_vreg();
     get_modrm(*current, &mod, &regop, &rm);
     switch (opcode) {
+      case 0x0a:
+        AppendToBuffer("vroundss %s,%s,", NameOfXMMRegister(regop),
+                       NameOfXMMRegister(vvvv));
+        current += PrintRightXMMOperand(current);
+        AppendToBuffer(",0x%x", *current++);
+        break;
       case 0x0b:
         AppendToBuffer("vroundsd %s,%s,", NameOfXMMRegister(regop),
                        NameOfXMMRegister(vvvv));
@@ -1516,6 +1522,12 @@ int DisassemblerX64::TwoByteOpcodeInstruction(byte* data) {
         current += PrintRightOperand(current);
         AppendToBuffer(",%s,%d", NameOfXMMRegister(regop), (*current) & 3);
         current += 1;
+      } else if (third_byte == 0x0a) {
+        get_modrm(*current, &mod, &regop, &rm);
+        AppendToBuffer("roundss %s,", NameOfXMMRegister(regop));
+        current += PrintRightXMMOperand(current);
+        AppendToBuffer(",0x%x", (*current) & 3);
+        current += 1;
       } else if (third_byte == 0x0b) {
         get_modrm(*current, &mod, &regop, &rm);
          // roundsd xmm, xmm/m64, imm8