ERROR: test_branch_ctr (__main__.DecoderTestCase)
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Traceback (most recent call last):
  File "openpower/decoder/isa/test_caller.py", line 146, in test_branch_ctr
    sim = self.run_tst_program(program)
  File "openpower/decoder/isa/test_caller.py", line 324, in run_tst_program
    simulator = run_tst(prog, initial_regs)
  File "openpower/decoder/isa/test_caller.py", line 72, in run_tst
    sim.run()
  File "/home/src/nmigen/nmigen/sim/core.py", line 165, in run
    while self.advance():
  File "/home/src/nmigen/nmigen/sim/core.py", line 156, in advance
    return self._engine.advance()
  File "/home/src/nmigen/nmigen/sim/pysim.py", line 319, in advance
    self._step()
  File "/home/src/nmigen/nmigen/sim/pysim.py", line 308, in _step
    process.run()
  File "/home/src/nmigen/nmigen/sim/_pycoro.py", line 123, in run
    self.coroutine.throw(exn)
  File "/home/src/nmigen/nmigen/sim/_pycoro.py", line 64, in run
    command = self.coroutine.send(response)
  File "/home/src/nmigen/nmigen/sim/core.py", line 81, in wrapper
    yield from process()
  File "openpower/decoder/isa/test_caller.py", line 65, in process
    yield from simulator.execute_one()
  File "/home/src/openpower-isa/src/openpower/decoder/isa/caller.py", line 861, in execute_one
    yield from self.call(opname)         # execute the instruction
  File "/home/src/openpower-isa/src/openpower/decoder/isa/caller.py", line 1135, in call
    results = info.func(self, *inputs)
  File "/home/src/openpower-isa/src/openpower/decoder/isa/caller.py", line 1318, in decorator
    result = func(*args, **kwargs)
  File "/home/src/openpower-isa/src/openpower/decoder/isa/sprset.py", line 29, in op_mtspr
    SPR[_n] = RS
NameError: name '_n' is not defined