> 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. Cheers, rdiez _______________________________________________ OpenRISC mailing list [email protected] http://lists.openrisc.net/listinfo/openrisc
