fix the type of value that is returned by bit-shift expression.
 fix the type of value that is returned by bit-shift expression.
"Ax" is larger than 16-bit.
fix the type of value that is returned by bit-shift expression.
fix comment.
Merge pull request #1039 from crimsonwoods/fix_the_type_of_opcode

Fix the type of value that is returned by bit shift expression.