Added roundss to the disassembler of x64 and ia32.

src/x64/disasm-x64.cc

Index: src/x64/disasm-x64.cc
diff --git a/src/x64/disasm-x64.cc b/src/x64/disasm-x64.cc
index 05b199d558df567d3fae301a15a84713d61313d6..a9532dc3ad9b97f8f238cefa7450b26c002dbed4 100644
--- a/src/x64/disasm-x64.cc
+++ b/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