On Sat, Apr 21, 2012 at 4:05 PM, R. Diez <[email protected]> wrote: > > >> I've posted my proposed change to the architecture spec on the wiki: >> http://opencores.org/or1k/Architecture_Specification#GPR0_usage.2C_implementation > > The change you've proposed in the Wiki makes the specification incompatible > with any implementation that actually hard-wires R0 to 0, which is allowed > according to the original spec, because the software is free to use the > OpenRISC CPU but not the C ABI. I don't think the spec should force the > l.movhi instruction either, the software should be free to use whatever means > it wants to clear R0. > > I would mention in the new spec that an implementation may have hard-wired R0 > to 0, and that writing 0 to R0 should not raise an exception on those > implementations.
Fair enough. Proposal has been updated. Thanks Julius _______________________________________________ OpenRISC mailing list [email protected] http://lists.openrisc.net/listinfo/openrisc
