From: Luke Kenneth Casson Leighton Date: Fri, 16 Oct 2020 18:09:40 +0000 (+0100) Subject: add extra (test dummy stage in trap to see if combinatorial latency is reduced X-Git-Tag: 24jan2021_ls180~142 X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=9fa4a517dc3f1fccac123de57f6c856e530f7ceb;p=soc.git add extra (test dummy stage in trap to see if combinatorial latency is reduced --- diff --git a/src/soc/fu/trap/pipeline.py b/src/soc/fu/trap/pipeline.py index 1fa867b5..c27a0e56 100644 --- a/src/soc/fu/trap/pipeline.py +++ b/src/soc/fu/trap/pipeline.py @@ -1,6 +1,27 @@ from nmutil.singlepipe import ControlBase from nmutil.pipemodbase import PipeModBaseChain from soc.fu.trap.main_stage import TrapMainStage +from soc.fu.trap.pipe_data import TrapOutputData +from nmutil.pipemodbase import PipeModBase +from nmigen import Module + +# gives a 1-clock delay to stop combinatorial link between in and out +class DummyTrapStage(PipeModBase): + def __init__(self, pspec): super().__init__(pspec, "dummy") + def ispec(self): return TrapOutputData(self.pspec) + def ospec(self): return TrapOutputData(self.pspec) + + def elaborate(self, platform): + m = Module() + m.d.comb += self.o.eq(self.i) # pass-through output + return m + + +class TrapDummyStages(PipeModBaseChain): + def get_chain(self): + dummy = DummyTrapStage(self.pspec) + return [dummy] + class TrapStages(PipeModBaseChain): def get_chain(self): @@ -13,10 +34,12 @@ class TrapBasePipe(ControlBase): ControlBase.__init__(self) self.pspec = pspec self.pipe1 = TrapStages(pspec) - self._eqs = self.connect([self.pipe1]) + self.pipe2 = TrapDummyStages(pspec) + self._eqs = self.connect([self.pipe1, self.pipe2]) def elaborate(self, platform): m = ControlBase.elaborate(self, platform) - m.submodules.pipe = self.pipe1 + m.submodules.pipe1 = self.pipe1 + m.submodules.pipe2 = self.pipe2 m.d.comb += self._eqs return m