src/nmutil/pipemodbase.py

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