Fast ART x86 interpreter

Port of ART Dalvik-style interpreter for x86.
See Bill's patch for details
https://android-review.googlesource.com/#/c/188977/

Included fixes
https://android-review.googlesource.com/#/c/196153/
ART: Mterp read barrier fix + minor cleanup

https://android-review.googlesource.com/#/c/196501/
ART: Mterp - remove redundant null check

Change-Id: If447e3a14088559e3aa0b82cb2c91721bea586ee
Signed-off-by: Serguei Katkov <serguei.i.katkov@intel.com>
diff --git a/runtime/interpreter/mterp/x86/binopLit8.S b/runtime/interpreter/mterp/x86/binopLit8.S
new file mode 100644
index 0000000..924685d
--- /dev/null
+++ b/runtime/interpreter/mterp/x86/binopLit8.S
@@ -0,0 +1,18 @@
+%default {"result":"%eax"}
+/*
+ * Generic 32-bit "lit8" binary operation.  Provide an "instr" line
+ * that specifies an instruction that performs "result = eax op ecx".
+ * This could be an x86 instruction or a function call.  (If the result
+ * comes back in a register other than r0, you can override "result".)
+ *
+ * For: add-int/lit8, rsub-int/lit8
+ *      and-int/lit8, or-int/lit8, xor-int/lit8,
+ *      shl-int/lit8, shr-int/lit8, ushr-int/lit8
+ */
+    /* binop/lit8 vAA, vBB, #+CC */
+    movzbl  2(rPC), %eax                    # eax <- BB
+    movsbl  3(rPC), %ecx                    # ecx <- ssssssCC
+    GET_VREG %eax %eax                      # eax <- rBB
+    $instr                                  # ex: addl %ecx,%eax
+    SET_VREG $result rINST
+    ADVANCE_PC_FETCH_AND_GOTO_NEXT 2