One supports branch instructions . the other does n ' t . and they both lack features common to general purpose microprocessors such as logic instructions and indirect memory access Gcx支持兩類后端,一類不支持轉(zhuǎn)移指令,另一類支持轉(zhuǎn)移指令,但兩者都缺乏一般微處理所具有的例如邏輯指令、存儲器間接訪問等特性。