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     def __init__(self, pspec, modname):
  20         self.modname = modname # use this to give a name to this module
  21         self.pspec = pspec
  22         self.i = self.ispec()
  23         self.o = self.ospec()
  24
  25     def process(self, i):
  26         return self.o
  27
  28     def setup(self, m, i):
  29         """ links module to inputs and outputs
  30         """
  31         setattr(m.submodules, self.modname, self)
  32         m.d.comb += self.i.eq(i)
  33
  34
  35 class PipeModBaseChain(DynamicPipe):
  36     """PipeModBaseChain: common code between stage-chained pipes
  37
  38     Links a set of combinatorial modules (get_chain) together
  39     and uses pspec.pipekls to dynamically select the pipeline type
  40     Also conforms to the Pipeline Stage API
  41     """
  42     def __init__(self, pspec):
  43         self.pspec = pspec
  44         self.chain = self.get_chain()
  45         super().__init__(pspec)
  46
  47     def ispec(self):
  48         """ returns the input spec of the first module in the chain
  49         """
  50         return self.chain[0].ispec()
  51
  52     def ospec(self):
  53         """ returns the output spec of the last module in the chain
  54         """
  55         return self.chain[-1].ospec()
  56
  57     def process(self, i):
  58         return self.o # ... returned here (see setup comment below)
  59
  60     def setup(self, m, i):
  61         """ links module to inputs and outputs
  62         """
  63         StageChain(self.chain).setup(m, i) # input linked here, through chain
  64         self.o = self.chain[-1].o # output is the last thing in the chain...