src/nmutil/pipemodbase.py

   1 """
   2     This work is funded through NLnet under Grant 2019-02-012
   3
   4     License: LGPLv3+
   5
   6     Associated bugreports:
   7     * https://bugs.libre-soc.org/show_bug.cgi?id=538
   8
   9 """
  10
  11 from nmigen import Elaboratable
  12 from ieee754.pipeline import DynamicPipe
  13 from nmutil.singlepipe import StageChain
  14
  15
  16 class PipeModBase(Elaboratable):
  17     """PipeModBase: common code between nearly every pipeline module
  18     """
  19
  20     def __init__(self, pspec, modname):
  21         self.modname = modname  # use this to give a name to this module
  22         self.pspec = pspec
  23         self.i = self.ispec()
  24         self.o = self.ospec()
  25
  26     def process(self, i):
  27         return self.o
  28
  29     def setup(self, m, i):
  30         """ links module to inputs and outputs
  31         """
  32         setattr(m.submodules, self.modname, self)
  33         m.d.comb += self.i.eq(i)
  34
  35
  36 class PipeModBaseChain(DynamicPipe):
  37     """PipeModBaseChain: common code between stage-chained pipes
  38
  39     Links a set of combinatorial modules (get_chain) together
  40     and uses pspec.pipekls to dynamically select the pipeline type
  41     Also conforms to the Pipeline Stage API
  42     """
  43
  44     def __init__(self, pspec):
  45         self.pspec = pspec
  46         self.chain = self.get_chain()
  47         super().__init__(pspec)
  48
  49     def ispec(self):
  50         """ returns the input spec of the first module in the chain
  51         """
  52         return self.chain[0].ispec()
  53
  54     def ospec(self):
  55         """ returns the output spec of the last module in the chain
  56         """
  57         return self.chain[-1].ospec()
  58
  59     def process(self, i):
  60         return self.o  # ... returned here (see setup comment below)
  61
  62     def setup(self, m, i):
  63         """ links module to inputs and outputs
  64         """
  65         StageChain(self.chain).setup(m, i)  # input linked here, through chain
  66         self.o = self.chain[-1].o  # output is the last thing in the chain...