RFR: 8314124: RISC-V: implement Base64 intrinsic - decoding [v3]

[Antonios Printezis]

On Thu, 22 Aug 2024 15:50:05 GMT, Hamlin Li <mli at openjdk.org> wrote:

>> src/hotspot/cpu/riscv/stubGenerator_riscv.cpp line 5462:
>> 
>>> 5460:     __ sub(length, send, soff);
>>> 5461:     // it's not guaranteed by java level, so do it explicitly
>>> 5462:     __ andi(length, length, -4);
>> 
>> Is it possible for `length == 0` here?
>
> No, this is guaranteed at java level.

Great. Maybe add a comment to that effect here?

>> src/hotspot/cpu/riscv/stubGenerator_riscv.cpp line 5470:
>> 
>>> 5468: 
>>> 5469:     // load the codec base address
>>> 5470:     __ la(codec, ExternalAddress((address) fromBase64));
>> 
>> any way to avoid the double `la` when `isURL == true`? I guess you'd need one more label and an extra branch? Not sure it's worth it.
>
> Seems not necessary, and I see other places, also on other cpus do the similar things.

OK!

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/20026#discussion_r1727509181
PR Review Comment: https://git.openjdk.org/jdk/pull/20026#discussion_r1727509434