On Wed, Oct 12, 2016 at 12:18:50AM +0200, Torbjörn Granlund wrote:
> PS. Does RISC-V have some sort of wait-for-interrupt instruction?  I
> mean, an instruction suitable for the kernel idle loop which waits for
> interrupt, allowing hardware and simulators to save energy.  If not, one
> should be proposed to the UCB folks.

The current privspec 1.9 (draft):


defines a WFI instruction, literally Wait For Interrupt (section 3.2.2).

However IIRC the reason qemu-system-riscv busy-waits is nothing to do
with this, it's because the interim device model is a big hack.  Soon
to be replaced with virtio, we are all hoping.


Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
Fedora Windows cross-compiler. Compile Windows programs, test, and
build Windows installers. Over 100 libraries supported.
devel mailing list -- devel@lists.fedoraproject.org
To unsubscribe send an email to devel-le...@lists.fedoraproject.org

Reply via email to