[Libre-soc-dev] video assembler

Jacob Lifshay programmerjake at gmail.com
Mon May 10 18:36:28 BST 2021


On Mon, May 10, 2021, 06:06 Luke Kenneth Casson Leighton <lkcl at lkcl.net>
wrote:

> On Monday, May 10, 2021, Lauri Kasanen <cand at gmx.com> wrote:
>
> >
> > What is the state of these simulators? Are they complete,
> > cycle-accurate, reporting the executed cycles?
>
>
> yes.
>
> the python one is cycle accurate one-for-one.


I'll note here that what lkcl probably means by cycle-accurate may be
different than expected: luke uses the definition where it can count the
number of executed instructions (or maybe the number of vector elements),
ascribing 1 cycle to each executed instruction.

That is different than the cycle-accurate that is best for benchmarking:
counting the actual time that would be taken on the final SoC, which would
need a model of parallel instruction scheduling, branch prediction, caches,
simd alus, etc.


Also, for handling files, i/o, and stuff from the python emulator, we could
add semihosting support where gdb executes all syscalls for us, that would
probably be pretty easy to setup.

Jacob


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