[PATCH] Add new counter-enable CSRs

[Nick Clifton]

Hi Palmer,

> 2017-02-22  Andrew Waterman  <andrew@sifive.com>
> 
>        * opcode/riscv-opc.h (CSR_SCOUNTEREN): New define.
>        (CSR_MCOUNTEREN): Likewise.
>        (scounteren): Declare register.
>        (mcounteren): Likewise.

Approved - please apply.

Cheers
  Nick