[计] load index register instruction

shū rù biàn zhǐ jì cún qì zhǐ lìng ㄕㄨ ㄖㄨˋ ㄅㄧㄢˋ ㄓˇ ㄐㄧˋ ㄘㄨㄣˊ ㄑㄧˋ ㄓˇ ㄌㄧㄥˋ