[RFC 1/2] RISC-V: Add Zvdota extension classes

[Jiawei]

On 2026/6/30 6:55, Jeffrey Law wrote:

>> diff --git a/bfd/elfxx-riscv.c b/bfd/elfxx-riscv.c
>> index 67fbf0f72ca..7714e5dcd49 100644
>> --- a/bfd/elfxx-riscv.c
>> +++ b/bfd/elfxx-riscv.c
>> @@ -1234,6 +1234,10 @@ static const struct riscv_implicit_subset 
>> riscv_implicit_subsets[] =
>>     {"zvfhmin", "+zve32f", check_implicit_always},
>>     {"zvfbfwma", "+zve32f,+zfbfmin", check_implicit_always},
>>     {"zvfbfmin", "+zve32f", check_implicit_always},
>> +  {"zvfqwdota8f", "+zve32f", check_implicit_always},
>> +  {"zvfwdota16bf", "+zve32f", check_implicit_always},
>> +  {"zvqwdota8i", "+zve32x", check_implicit_always},
>> +  {"zvqwdota16i", "+zve64x", check_implicit_always},
> I'd double-check the zvfwdota16bf entry. I haven't looked real closely 
> and it's just a bit odd looking that the 16i case is +zve64x, but the 
> 16 case is ust +zve32f rather than +zve64f.

I checked the currently spec PR and it defined that the Zvfwdota16bf 
extension depends on the Zve32f extension.
The note description says "as an unordered FP32 dot-product instruction 
is not provided for the same" So I think it is correct here.
https://github.com/riscv/riscv-isa-manual/pull/2618/changes#diff-acc7be3418935b447f6db653029f86cc07b6b27237862bd70f5c49aa881b159dR121

>> diff --git a/gas/NEWS b/gas/NEWS
>> index e384d1135c0..ddb7983aea0 100644
>> --- a/gas/NEWS
>> +++ b/gas/NEWS
>> @@ -1,5 +1,8 @@
>>   -*- text -*-
>>   +* Add support for RISC-V standard extensions:
>> +  zvqwdota8i, zvqwdota16i, zvfwdota16bf and zvfqwdota8f v1.0.
>> +
>>   Changes in 2.46:
>>     * Add support for AMD Zen6 processor.
> The NEWS entry probably needs updating given the other changes that 
> have gone in recently.
>
> I'd like to include this in the upcoming release, so please 
> double-check that one entry noted above and adjust the NEWS file. With 
> those changes this is OK.  I can handle pushing the final version.
>
> Jeff

Thanks for the review Jeff.  I will update the rebased patches soon.


Best,
Jiawei