[libre-riscv-dev] [hw-dev] Re: 6600-style out-of-order scoreboard designs (ariane)

[Luke Kenneth Casson Leighton]

On Wed, May 22, 2019 at 8:44 AM Luke Kenneth Casson Leighton
<lkcl at lkcl.net> wrote:

> it's working!  the dependency-matrix version (FU-Regs + FU-FU) is
> actually working.  for a given definition of "work".
>
> at the moment, there is a bug where if an instruction uses a src
> register also as a dest register, the matrices believe that this is
> both a read-hazard (on itself) *and* a write-hazard (on itself).  this
> because the test for read-dependencies and the test for
> write-dependencies is in the same clock cycle.

 fixed.  required removing the dependencies down the identity diagonal
on the FU-FU matrix.  this basically representing a Function Unit
dependencies on itself.

 aside from not having a formal test for the correctness, as more
random tests are run i am gaining a higher degree of confidence that
the implementation is correct.

 took long enough.

l.