Re: [RFC PATCH 6/6] riscv: Add BLAKE2s V implementation

[Björn Töpel]

Charlie Jenkins <charlie@xxxxxxxxxxxx> writes:

>> +.macro VROR REG BITS TMPREG
>> +	vmv.v.v		\TMPREG, \REG
>> +	vsrl.vi		\REG, \REG, \BITS
>> +	vsll.vi		\TMPREG, \TMPREG, 32-\BITS
>> +	vor.vv		\REG, \REG, \TMPREG
>> +.endm
>
> This seems like it would be a good candidate to use the Zvkb extension
> that has vector rotate [1]. It would be a pain to use because you need
> two versions of the roundloop, but you could get away with 1 extra
> branch/nop and save 3 instructions per VROR which looks like it happens
> 8*10 times, so 239 fewer instructions.
>
> [1] https://github.com/riscv/riscv-crypto/releases

Indeed! Thanks!


Björn