[Question] About scaling factor of Enhanced Counter Virtualization

[zhukeqian]

Hi all,

We are studying Enhanced Counter Virtualization (introduced by ARMv8.6 extension), and here is a question
raised by Biaoxiang Ye <yebiaoxiang at huawei.com>:

Described in the ARMv8.6 Extension Specification:
Note: the scaling factor CNTSCALE is designed as a 2.62 bit fixed point number, so permitting a scaling up by
(nearly) a factor 4. The scaling factor CNTISCALE is signed as an 8.56 number for the scaling of the values
written into the timers for comparison with the actual count. This implies that the greatest scaling down of the
counter supported in (nearly) a factor of *512*.

We think the number "512" should be "256" (2^8), or do we miss something?

Thanks,
Keqian