Support for MCYCLEH, MINSTRETH, CYCLEH, TIMEH and INSTRETH in 32-bit mode

[spersvold]

Hi,

In 32-bit mode it would be nice to get access to the full 64-bit wide cycle and instruction counters for precision timing. Currently there's an exception of code references these CSR registers.

I'm attaching a patch that adds support for this. Please consider. 0001-Added-support-for-MCYCLEH-MINSTRETH-CYCLEH-TIMEH-and.patch.txt

Thanks! -- Steffen

[spersvold]

I've also added a pull request #847

[MikeOpenHWGroup]

A pull-request to address this issue (#847) has been merged in, so I will close this issue.