[x64] add disasm for two fp instructions

BUG=
R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/146583002

Patch from Weiliang Lin <weiliang.lin@intel.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19022 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/x64/disasm-x64.cc

@@ -934,6 +934,7 @@ int DisassemblerX64::RegisterFPUInstruction(int escape_opcode,
             case 0xF5: mnem = "fprem1"; break;
             case 0xF7: mnem = "fincstp"; break;
             case 0xF8: mnem = "fprem"; break;
+            case 0xFC: mnem = "frndint"; break;
             case 0xFD: mnem = "fscale"; break;
             case 0xFE: mnem = "fsin"; break;
             case 0xFF: mnem = "fcos"; break;
@@ -956,6 +957,8 @@ int DisassemblerX64::RegisterFPUInstruction(int escape_opcode,
         has_register = true;
       } else if (modrm_byte  == 0xE2) {
         mnem = "fclex";
+      } else if (modrm_byte == 0xE3) {
+        mnem = "fninit";
       } else {
         UnimplementedInstruction();
       }

test/cctest/test-disasm-ia32.cc

@@ -349,6 +349,8 @@ TEST(DisasmIa320) {
   __ fdivp(3);
   __ fcompp();
   __ fwait();
+  __ frndint();
+  __ fninit();
   __ nop();
 
   // SSE instruction

test/cctest/test-disasm-x64.cc

@@ -330,6 +330,8 @@ TEST(DisasmX64) {
   __ fdivp(3);
   __ fcompp();
   __ fwait();
+  __ frndint();
+  __ fninit();
   __ nop();
 
   // SSE instruction