Re: [libre-riscv-dev] daily kan-ban update 23may2020

[Luke Kenneth Casson Leighton <lkcl@lkcl.net>]

---
crowd-funded eco-conscious hardware: https://www.crowdsupply.com/eoma68

On Sat, May 23, 2020 at 10:39 PM Cole Poirier <colepoirier@gmail.com> wrote:
>
> On May 23 2020, at 1:59 pm, Luke Kenneth Casson Leighton <lkcl@lkcl.net> wrote:
> > soc.fu they are now common base classes.  the code is exactly the
> > same, it
> > is just split.
>
> I tried fixing this the naive way, by just substituting CommonInput
> stageStage for LogicalInputStage

why?

look at the class:

class LogicalInputStage(CommonInputStage):
    def __init__(self, pspec):
        super().__init__(pspec, "input")   <---- must be initialised
with an argument, "input"

    def ispec(self):
        return LogicalInputData(self.pspec)   <--- CommonInputStage
does not have this

    def ospec(self):
        return LogicalInputData(self.pspec)   <---- CommonInputStage
does not have this

    def elaborate(self, platform):
        m = super().elaborate(platform) # covers A-invert, carry, excludes SO
        comb = m.d.comb
        ctx = self.i.ctx

        # operand b
        comb += self.o.b.eq(self.i.b)    <----   CommonInputStage does
not do this

        return m

so what you are trying to do is guaranteed to fail, on four separate counts.

* no initialisation of CommonInputStage 1st parameter
* no ispec
* no ospec
* parameter B will not be copied over

so, don't do that.

l.

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