[Libre-soc-dev] fantastically-weird regfile

[Luke Kenneth Casson Leighton]

On 12/14/20, Jacob Lifshay <programmerjake at gmail.com> wrote:
> On Sun, Dec 13, 2020 at 5:50 PM Luke Kenneth Casson Leighton
> <lkcl at lkcl.net> wrote:
>>
>> On 12/14/20, Jacob Lifshay <programmerjake at gmail.com> wrote:
>> > That's very similar to what I already did for int and fp registers, see:
>> >
>> > https://libre-soc.org/openpower/sv/svp_rewrite/svp64/
>> >
>> jacob once it's been documented the regfile stratification,
>> allocation, port numbering etc can be evaluated, as well as the Dep
>> Matrix layout
>
> Basic summary: they're conceptually organized differently, but
> microarchitecturally they are the exact same flat reg-file we always
> had.

okaay, wheww :)

> The purpose of the organization is to make it obvious how the standard
> 32 registers fit into the scheme, and how it can be expanded in the
> future (by adding more registers between each standard register,
> rather than adding more registers at the end, making instructions be
> automatically able to address all the new registers by just using a
> larger VL).

can you illustrate / make a note of that with a piece of pseudocode
for-loop for i in range(VL) then how the mapping would work?

i'd like to make sure these ideas are recorded.

l.