src/soc/decoder/power_fieldsn.py

   1 from collections import OrderedDict
   2 from soc.decoder.power_fields import DecodeFields, BitRange
   3 from nmigen import Module, Elaboratable, Signal, Cat
   4 from nmigen.cli import rtlil
   5
   6
   7 class SignalBitRange(BitRange):
   8     def __init__(self, signal):
   9         BitRange.__init__(self)
  10         self.signal = signal
  11
  12     def _rev(self, k):
  13         width = self.signal.shape()[0]
  14         return width-1-k
  15
  16     def __getitem__(self, subs):
  17         # *sigh* field numberings are bit-inverted.  PowerISA 3.0B section 1.3.2
  18         print (dir(self))
  19         print (self.items())
  20         if isinstance(subs, slice):
  21             res = []
  22             print (subs)
  23             start, stop, step = subs.start, subs.stop, subs.step
  24             if step is None:
  25                 step = 1
  26             if start is None:
  27                 start = 0
  28             if stop is None:
  29                 stop = -1
  30             if start < 0:
  31                 start = len(self) - start - 1
  32             if stop < 0:
  33                 stop = len(self) - stop - 1
  34             print ("range", start, stop, step)
  35             for t in range(start, stop, step):
  36                 k = OrderedDict.__getitem__(self, t)
  37                 print ("t", t, k)
  38                 res.append(self.signal[self._rev(k)]) # reverse-order here
  39             return Cat(*res)
  40         else:
  41             k = OrderedDict.__getitem__(self, subs)
  42             return self.signal[self._rev(k)] # reverse-order here
  43
  44         print ("translated", subs, translated)
  45
  46
  47 class SigDecode(Elaboratable):
  48
  49     def __init__(self, width):
  50         self.opcode_in = Signal(width, reset_less=False)
  51         self.df = DecodeFields(SignalBitRange, [self.opcode_in])
  52         self.df.create_specs()
  53         self.x_s = Signal(len(self.df.FormX.S), reset_less=True)
  54         self.x_sh = Signal(len(self.df.FormX.SH), reset_less=True)
  55         self.dq_xs_s = Signal(len(self.df.FormDQ.SX_S), reset_less=True)
  56
  57     def elaborate(self, platform):
  58         m = Module()
  59         comb = m.d.comb
  60         comb += self.x_s.eq(self.df.FormX.S[0])
  61         comb += self.x_sh.eq(self.df.FormX.SH[0:-1])
  62         comb += self.dq_xs_s.eq(self.df.FormDQ.SX_S[0:-1])
  63         return m
  64
  65     def ports(self):
  66         return [self.opcode_in, self.x_s, self.x_sh]
  67
  68 def create_sigdecode():
  69     s = SigDecode(32)
  70     return s
  71
  72 if __name__ == '__main__':
  73     sigdecode = create_sigdecode()
  74     vl = rtlil.convert(sigdecode, ports=sigdecode.ports())
  75     with open("decoder.il", "w") as f:
  76         f.write(vl)
  77