Re: Is it safe to extend LMUL's maximum value based on current rc2 version?


Bruce Hoult
 

On Tue, Oct 5, 2021 at 11:30 PM Feng Chuang <Chuang_Feng@...> wrote:
hi  Krste and all friends,

Per my understanding, if I extend the vector architecture register number (to be larger than 32) and extend maximum LMUL value to be larger than 8, current vector extension (v1.0) still works fine in terms of completeness and correctness, given mask value can be read from multiple continuous vector registers and even with a mask register specifier as indicated in the spec note for future extension.

I'm trying to understand the reason for this.

Do you need more than 32 register variables for some algorithm? (of course unrolling a loop can use arbitrary numbers of registers) How will you address them? WIth new longer instruction formats?

If you're addressing more registers only by making LMUL bigger, what advantage does that have over simply making VLEN bigger?
 

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