def alu_controller(alu_op,funct7,funct3):               #alu_op来自主控制器，funct7和funct3来自指令的特定部位   返回alu_ctrl
    if alu_op=='00':
        opreation='00000'        #lw.sw.auipc
    elif alu_op=='01':
        if funct3=='000':
            opreation='00101'    #beq
        elif funct3=='001':
            opreation='00110'    #bne
        elif funct3=='100':
            opreation='00111'    #blt
        elif funct3=='101':
            opreation='01000'    #bge
        elif funct3=='110':
            opreation='01001'    #bltu
        elif funct3=='111':
            opreation='01010'    #bgeu
        else:
            opreation='00000'
    elif alu_op=='10':
        if funct3=='000':
            if funct7=='0100000':   #sub
                opreation='00001'
            else:                   #add,addi
                opreation='00000'
        elif funct3=='100':
            opreation='01100'        #xor,xori
        elif funct3=='110':
            opreation='00010'        #or,ori
        elif funct3=='111':
            opreation='00011'        #and, andi
        elif funct3=='010':
            opreation='00100'        #slt,slti
        elif funct3=='001':
            opreation='01101'        #sll,slli   未存在
        elif funct3=='011':
            opreation='01110'        #sliu,sltiu 未存在
        elif funct3=='101':
            if funct7=='0100000':   #sra,srai
                opreation='01111'
            else:                   #srl,srli
                opreation='10000'
        else:
            opreation='00000'
    elif alu_op=='11':              #jal
        opreation='01011'
    else:
        opreation='00000'
    return opreation