Re: [Qemu-devel] [PATCH v5 18/35] target/arm: Implement SVE Floating Point Multiply Indexed Group

[Richard Henderson]

On 06/25/2018 10:47 AM, Peter Maydell wrote:
>> +                           status, vsz, vsz, a->index * 2 + a->sub,
> Why are we multiplying the index by 2 here? Are we just encoding
> (index, sub) into a constant to pull out again the other side?
> If so, comment might help. (Also I find shifts and ors make it
> clearer that we're just shifting values around; multiplication
> and addition to me implies that we're really doing arithmetic.)
> 

Yes, this is just encoding.
I sometimes use multiply and add to avoid needing extra parenthesis.


r~