src/scoreboard/shadow_fn.py

   1 from nmigen.compat.sim import run_simulation
   2 from nmigen.cli import verilog, rtlil
   3 from nmigen import Module, Signal, Cat, Elaboratable
   4 from nmutil.latch import SRLatch
   5
   6
   7 class ShadowFn(Elaboratable):
   8     """ implements shadowing 11.5.1, p55, just the individual shadow function
   9     """
  10     def __init__(self, syncreset=False):
  11
  12         self.syncreset = syncreset
  13
  14         # inputs
  15         self.issue_i = Signal(reset_less=True)
  16         self.shadow_i  = Signal(reset_less=True)
  17         self.reset_i  = Signal(reset_less=True)
  18         self.s_fail_i  = Signal(reset_less=True)
  19         self.s_good_i  = Signal(reset_less=True)
  20
  21         # outputs
  22         self.shadow_o = Signal(reset_less=True)
  23         self.recover_o = Signal(reset_less=True)
  24
  25     def elaborate(self, platform):
  26         m = Module()
  27         m.submodules.sl = sl = SRLatch(sync=False)
  28
  29         reset_r = Signal()
  30         if self.syncreset:
  31             m.d.comb += reset_r.eq(self.s_good_i | self.s_fail_i | self.reset_i)
  32         else:
  33             m.d.comb += reset_r.eq(self.s_good_i | self.s_fail_i | self.reset_i)
  34
  35         m.d.comb += sl.s.eq(self.shadow_i & self.issue_i & \
  36                             ~self.s_good_i & ~reset_r)
  37         m.d.comb += sl.r.eq(self.reset_i | reset_r | self.s_good_i | \
  38                             (self.issue_i & ~self.shadow_i))
  39         m.d.comb += self.recover_o.eq(sl.qlq & self.s_fail_i)
  40         m.d.comb += self.shadow_o.eq(sl.qlq)
  41
  42         return m
  43
  44     def __iter__(self):
  45         yield self.issue_i
  46         yield self.s_reset_i
  47         yield self.shadow_i
  48         yield self.s_fail_i
  49         yield self.s_good_i
  50         yield self.shadow_o
  51         yield self.recover_o
  52
  53     def ports(self):
  54         return list(self)
  55
  56
  57 def shadow_fn_unit_sim(dut):
  58     yield dut.dest_i.eq(1)
  59     yield dut.issue_i.eq(1)
  60     yield
  61     yield dut.issue_i.eq(0)
  62     yield
  63     yield dut.src1_i.eq(1)
  64     yield dut.issue_i.eq(1)
  65     yield
  66     yield
  67     yield
  68     yield dut.issue_i.eq(0)
  69     yield
  70     yield dut.go_rd_i.eq(1)
  71     yield
  72     yield dut.go_rd_i.eq(0)
  73     yield
  74     yield dut.go_wr_i.eq(1)
  75     yield
  76     yield dut.go_wr_i.eq(0)
  77     yield
  78
  79
  80 def test_shadow_fn_unit():
  81     dut = ShadowFn()
  82     vl = rtlil.convert(dut, ports=dut.ports())
  83     with open("test_shadow_fn_unit.il", "w") as f:
  84         f.write(vl)
  85
  86     run_simulation(dut, shadow_fn_unit_sim(dut),
  87                    vcd_name='test_shadow_fn_unit.vcd')
  88
  89 if __name__ == '__main__':
  90     test_shadow_fn_unit()