riscv-formal-nmigen/nmigen/test/test_lib_coding.py

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2020-08-19 14:56:26 +08:00
from .utils import *
from ..hdl import *
from ..asserts import *
from ..back.pysim import *
from ..lib.coding import *
class EncoderTestCase(FHDLTestCase):
def test_basic(self):
enc = Encoder(4)
def process():
self.assertEqual((yield enc.n), 1)
self.assertEqual((yield enc.o), 0)
yield enc.i.eq(0b0001)
yield Settle()
self.assertEqual((yield enc.n), 0)
self.assertEqual((yield enc.o), 0)
yield enc.i.eq(0b0100)
yield Settle()
self.assertEqual((yield enc.n), 0)
self.assertEqual((yield enc.o), 2)
yield enc.i.eq(0b0110)
yield Settle()
self.assertEqual((yield enc.n), 1)
self.assertEqual((yield enc.o), 0)
sim = Simulator(enc)
sim.add_process(process)
sim.run()
class PriorityEncoderTestCase(FHDLTestCase):
def test_basic(self):
enc = PriorityEncoder(4)
def process():
self.assertEqual((yield enc.n), 1)
self.assertEqual((yield enc.o), 0)
yield enc.i.eq(0b0001)
yield Settle()
self.assertEqual((yield enc.n), 0)
self.assertEqual((yield enc.o), 0)
yield enc.i.eq(0b0100)
yield Settle()
self.assertEqual((yield enc.n), 0)
self.assertEqual((yield enc.o), 2)
yield enc.i.eq(0b0110)
yield Settle()
self.assertEqual((yield enc.n), 0)
self.assertEqual((yield enc.o), 1)
sim = Simulator(enc)
sim.add_process(process)
sim.run()
class DecoderTestCase(FHDLTestCase):
def test_basic(self):
dec = Decoder(4)
def process():
self.assertEqual((yield dec.o), 0b0001)
yield dec.i.eq(1)
yield Settle()
self.assertEqual((yield dec.o), 0b0010)
yield dec.i.eq(3)
yield Settle()
self.assertEqual((yield dec.o), 0b1000)
yield dec.n.eq(1)
yield Settle()
self.assertEqual((yield dec.o), 0b0000)
sim = Simulator(dec)
sim.add_process(process)
sim.run()
class ReversibleSpec(Elaboratable):
def __init__(self, encoder_cls, decoder_cls, args):
self.encoder_cls = encoder_cls
self.decoder_cls = decoder_cls
self.coder_args = args
def elaborate(self, platform):
m = Module()
enc, dec = self.encoder_cls(*self.coder_args), self.decoder_cls(*self.coder_args)
m.submodules += enc, dec
m.d.comb += [
dec.i.eq(enc.o),
Assert(enc.i == dec.o)
]
return m
class HammingDistanceSpec(Elaboratable):
def __init__(self, distance, encoder_cls, args):
self.distance = distance
self.encoder_cls = encoder_cls
self.coder_args = args
def elaborate(self, platform):
m = Module()
enc1, enc2 = self.encoder_cls(*self.coder_args), self.encoder_cls(*self.coder_args)
m.submodules += enc1, enc2
m.d.comb += [
Assume(enc1.i + 1 == enc2.i),
Assert(sum(enc1.o ^ enc2.o) == self.distance)
]
return m
class GrayCoderTestCase(FHDLTestCase):
def test_reversible(self):
spec = ReversibleSpec(encoder_cls=GrayEncoder, decoder_cls=GrayDecoder, args=(16,))
self.assertFormal(spec, mode="prove")
def test_distance(self):
spec = HammingDistanceSpec(distance=1, encoder_cls=GrayEncoder, args=(16,))
self.assertFormal(spec, mode="prove")