src/nmutil/test/test_lut.py

   1 # SPDX-License-Identifier: LGPL-3-or-later
   2 # See Notices.txt for copyright information
   3
   4 from contextlib import contextmanager
   5 import unittest
   6 from hashlib import sha256
   7 import shutil
   8 import subprocess
   9 from nmigen.back import rtlil
  10 import textwrap
  11 from nmigen.hdl.ast import AnyConst, Assert, Signal
  12 from nmigen.hdl.dsl import Module
  13 from nmigen.hdl.ir import Fragment
  14 from nmutil.get_test_path import get_test_path
  15 from nmutil.lut import BitwiseMux, BitwiseLut, TreeBitwiseLut
  16 from nmigen.sim import Simulator, Delay
  17
  18
  19 @contextmanager
  20 def do_sim(test_case, dut, traces=()):
  21     sim = Simulator(dut)
  22     path = get_test_path(test_case, "sim_test_out")
  23     path.parent.mkdir(parents=True, exist_ok=True)
  24     vcd_path = path.with_suffix(".vcd")
  25     gtkw_path = path.with_suffix(".gtkw")
  26     with sim.write_vcd(vcd_path.open("wt", encoding="utf-8"),
  27                        gtkw_path.open("wt", encoding="utf-8"),
  28                        traces=traces):
  29         yield sim
  30
  31
  32 # copied from ieee754fpu/src/ieee754/partitioned_signal_tester.py
  33 def formal(test_case, hdl, *, base_path="formal_test_temp"):
  34     hdl = Fragment.get(hdl, platform="formal")
  35     path = get_test_path(test_case, base_path)
  36     shutil.rmtree(path, ignore_errors=True)
  37     path.mkdir(parents=True)
  38     sby_name = "config.sby"
  39     sby_file = path / sby_name
  40
  41     sby_file.write_text(textwrap.dedent(f"""\
  42     [options]
  43     mode prove
  44     depth 1
  45     wait on
  46
  47     [engines]
  48     smtbmc
  49
  50     [script]
  51     read_rtlil top.il
  52     prep
  53
  54     [file top.il]
  55     {rtlil.convert(hdl)}
  56     """), encoding="utf-8")
  57     sby = shutil.which('sby')
  58     assert sby is not None
  59     with subprocess.Popen(
  60         [sby, sby_name],
  61         cwd=path, text=True, encoding="utf-8",
  62         stdin=subprocess.DEVNULL, stdout=subprocess.PIPE
  63     ) as p:
  64         stdout, stderr = p.communicate()
  65         if p.returncode != 0:
  66             test_case.fail(f"Formal failed:\n{stdout}")
  67
  68
  69 def hash_256(v):
  70     return int.from_bytes(
  71         sha256(bytes(v, encoding='utf-8')).digest(),
  72         byteorder='little'
  73     )
  74
  75
  76 class TestBitwiseMux(unittest.TestCase):
  77     def test(self):
  78         width = 2
  79         dut = BitwiseMux(width)
  80
  81         def case(sel, t, f, expected):
  82             with self.subTest(sel=bin(sel), t=bin(t), f=bin(f)):
  83                 yield dut.sel.eq(sel)
  84                 yield dut.t.eq(t)
  85                 yield dut.f.eq(f)
  86                 yield Delay(1e-6)
  87                 output = yield dut.output
  88                 with self.subTest(output=bin(output), expected=bin(expected)):
  89                     self.assertEqual(expected, output)
  90
  91         def process():
  92             for sel in range(2 ** width):
  93                 for t in range(2 ** width):
  94                     for f in range(2**width):
  95                         expected = 0
  96                         for i in range(width):
  97                             if sel & 2 ** i:
  98                                 if t & 2 ** i:
  99                                     expected |= 2 ** i
 100                             elif f & 2 ** i:
 101                                 expected |= 2 ** i
 102                         yield from case(sel, t, f, expected)
 103         with do_sim(self, dut, [dut.sel, dut.t, dut.f, dut.output]) as sim:
 104             sim.add_process(process)
 105             sim.run()
 106
 107     def test_formal(self):
 108         width = 2
 109         dut = BitwiseMux(width)
 110         m = Module()
 111         m.submodules.dut = dut
 112         m.d.comb += dut.sel.eq(AnyConst(width))
 113         m.d.comb += dut.f.eq(AnyConst(width))
 114         m.d.comb += dut.t.eq(AnyConst(width))
 115         for i in range(width):
 116             with m.If(dut.sel[i]):
 117                 m.d.comb += Assert(dut.t[i] == dut.output[i])
 118             with m.Else():
 119                 m.d.comb += Assert(dut.f[i] == dut.output[i])
 120         formal(self, m)
 121
 122
 123 class TestBitwiseLut(unittest.TestCase):
 124     def tst(self, cls):
 125         dut = cls(3, 16)
 126         mask = 2 ** dut.width - 1
 127         lut_mask = 2 ** dut.lut.width - 1
 128         if cls is TreeBitwiseLut:
 129             mux_inputs = {k: s.name for k, s in dut._mux_inputs.items()}
 130             self.assertEqual(mux_inputs, {
 131                 (): 'mux_input_0bxxx',
 132                 (False,): 'mux_input_0bxx0',
 133                 (False, False): 'mux_input_0bx00',
 134                 (False, False, False): 'mux_input_0b000',
 135                 (False, False, True): 'mux_input_0b100',
 136                 (False, True): 'mux_input_0bx10',
 137                 (False, True, False): 'mux_input_0b010',
 138                 (False, True, True): 'mux_input_0b110',
 139                 (True,): 'mux_input_0bxx1',
 140                 (True, False): 'mux_input_0bx01',
 141                 (True, False, False): 'mux_input_0b001',
 142                 (True, False, True): 'mux_input_0b101',
 143                 (True, True): 'mux_input_0bx11',
 144                 (True, True, False): 'mux_input_0b011',
 145                 (True, True, True): 'mux_input_0b111'
 146             })
 147
 148         def case(in0, in1, in2, lut):
 149             expected = 0
 150             for i in range(dut.width):
 151                 lut_index = 0
 152                 if in0 & 2 ** i:
 153                     lut_index |= 2 ** 0
 154                 if in1 & 2 ** i:
 155                     lut_index |= 2 ** 1
 156                 if in2 & 2 ** i:
 157                     lut_index |= 2 ** 2
 158                 if lut & 2 ** lut_index:
 159                     expected |= 2 ** i
 160             with self.subTest(in0=bin(in0), in1=bin(in1), in2=bin(in2),
 161                               lut=bin(lut)):
 162                 yield dut.inputs[0].eq(in0)
 163                 yield dut.inputs[1].eq(in1)
 164                 yield dut.inputs[2].eq(in2)
 165                 yield dut.lut.eq(lut)
 166                 yield Delay(1e-6)
 167                 output = yield dut.output
 168                 with self.subTest(output=bin(output), expected=bin(expected)):
 169                     self.assertEqual(expected, output)
 170
 171         def process():
 172             for case_index in range(100):
 173                 with self.subTest(case_index=case_index):
 174                     in0 = hash_256(f"{case_index} in0") & mask
 175                     in1 = hash_256(f"{case_index} in1") & mask
 176                     in2 = hash_256(f"{case_index} in2") & mask
 177                     lut = hash_256(f"{case_index} lut") & lut_mask
 178                     yield from case(in0, in1, in2, lut)
 179         with do_sim(self, dut, [*dut.inputs, dut.lut, dut.output]) as sim:
 180             sim.add_process(process)
 181             sim.run()
 182
 183     def tst_formal(self, cls):
 184         dut = cls(3, 16)
 185         m = Module()
 186         m.submodules.dut = dut
 187         m.d.comb += dut.inputs[0].eq(AnyConst(dut.width))
 188         m.d.comb += dut.inputs[1].eq(AnyConst(dut.width))
 189         m.d.comb += dut.inputs[2].eq(AnyConst(dut.width))
 190         m.d.comb += dut.lut.eq(AnyConst(dut.lut.width))
 191         for i in range(dut.width):
 192             lut_index = Signal(dut.input_count, name=f"lut_index_{i}")
 193             for j in range(dut.input_count):
 194                 m.d.comb += lut_index[j].eq(dut.inputs[j][i])
 195             for j in range(dut.lut.width):
 196                 with m.If(lut_index == j):
 197                     m.d.comb += Assert(dut.lut[j] == dut.output[i])
 198         formal(self, m)
 199
 200     def test(self):
 201         self.tst(BitwiseLut)
 202
 203     def test_tree(self):
 204         self.tst(TreeBitwiseLut)
 205
 206     def test_formal(self):
 207         self.tst_formal(BitwiseLut)
 208
 209     def test_tree_formal(self):
 210         self.tst_formal(TreeBitwiseLut)
 211
 212
 213 if __name__ == "__main__":
 214     unittest.main()