def _backpatch(self):
        'Backpatch immediates of branch _instructions'

        labels = self._fix_labels()
        for i, label in self._backpatch_list:
            if label not in labels:
                raise AssembleError('Undefined label {}'.format(label))

            insn = self._instructions[i]
            assert(isinstance(insn, BranchInsn))
            assert(insn.rel)

            insn.immediate = 8*(i + 4) - labels[label]
        self._backpatch_list = []
dataset/ETHPy150Open nineties/py-videocore/videocore/assembler.py/Assembler._backpatch/swapped operands of `-`