[Libre-soc-dev] remap status?

Luke Kenneth Casson Leighton lkcl at lkcl.net
Fri May 28 14:14:50 BST 2021


On Fri, May 28, 2021 at 1:46 PM Lauri Kasanen <cand at gmx.com> wrote:

> Hi,
>
> Is remap implemented in pypowersim?
>

i hadn't added it but could easily prioritise it.  Cesar will love that :)


> The x86 and ppc versions of mp3_0 do a lot of extra work in order to
> vectorize it and be cache friendly. The C version just accesses the
> elements as needed - array[0], array[64], ... at an offset of 64
> floats each.
>

blegh.


> I believe remap would let me express the C version simply, loading at
> those offsets.


this is the general strategic idea, with the effect being to reduce
program size.

https://libre-soc.org/openpower/sv/remap/

the offset allowed is between 0 and 63.  zdimsz ydimsz and xdimsz may be
between 1 and 64.  do you need beyond that?

if so, i just noticed that applydim *might* be redundant (set the dimension
to 1 and it's the same effect).

/mp3_0_apply_window_float.s is very unclear (arbitrary non-sequential
register allocations).

could you outline in pseudo-assembler what you need?

l.


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