def word_ret(opcode, syntax, xregs, fregs, imms, symbols):
    tpe = CF_RET
    if (syntax == 'mret'):
        epc = 'mepc'
    elif (syntax == 'sret'):
        epc = 'sepc'
    else:
        epc = 'uepc'
    insts = ['la xreg0, symbol', 'csrrw zero, {}, xreg0'.format(epc), syntax]
    xregs.append('xreg0')
    symbols.append('symbol')
    return (tpe, insts)
def word_ret(opcode, syntax, xregs, fregs, imms, symbols):
    tpe = CF_RET
    if (syntax == 'mret'):
        epc = 'mepc'
    elif (syntax == 'sret'):
        epc = 'sepc'
    else:
        epc = 'uepc'
    insts = ['la xreg0, symbol', 'csrrw zero, {}, xreg0'.format(epc), syntax]
    xregs.append('xreg0')
    symbols.append('symbol')
    return (tpe, insts)