70 lines
1.8 KiB
Python
70 lines
1.8 KiB
Python
import unittest
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import random
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from litex.gen import *
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from litedram.phy.bitslip import BitSlip
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class BitSlipModel:
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def __init__(self, data_width, latency):
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self.data_width = data_width
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self.latency = latency
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def simulate(self, bitslip, sequence):
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# prepare sequence for simulation
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s = [0]*self.latency
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for d in sequence:
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s.append(d)
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# simulate bitslip
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r = []
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for i in range(len(s)-1):
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v = (s[i+1] & (2**bitslip-1)) << (self.data_width-bitslip)
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v |= (s[i] >> bitslip) & (2**(self.data_width-bitslip)-1)
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r.append(v)
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return r
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def main_generator(dut):
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dut.o_sequence = []
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yield dut.value.eq(dut.bitslip)
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for i, data in enumerate(dut.i_sequence):
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yield dut.i.eq(data)
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dut.o_sequence.append((yield dut.o))
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yield
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class TestBitSlip(unittest.TestCase):
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def bitslip_test(self, data_width, length=128):
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prng = random.Random(42)
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sequence = [prng.randrange(2**data_width) for i in range(length)]
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for i in range(data_width):
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dut = BitSlip(data_width)
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dut.bitslip = i
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dut.i_sequence = sequence
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run_simulation(dut, main_generator(dut))
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model = BitSlipModel(data_width, 4)
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m_sequence = model.simulate(i, sequence)
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self.assertEqual(dut.o_sequence, m_sequence[:len(dut.o_sequence)])
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def test_bitslip_4b(self):
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self.bitslip_test(4)
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def test_bitslip_8b(self):
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self.bitslip_test(8)
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def test_bitslip_16b(self):
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self.bitslip_test(16)
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def test_bitslip_32b(self):
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self.bitslip_test(32)
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def test_bitslip_64b(self):
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self.bitslip_test(64)
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def test_bitslip_128b(self):
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self.bitslip_test(128)
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