On Tue, Mar 20, 2012 at 10:06:16AM +0000, R. Diez wrote: > Hi all: > > I found the following about R0 in the architecture specification: > > > > R0 is used as a constant zero. > > That is the basic assumption which everybody counts upon, therefore... > > > > R0 should never be used as a destination register. > > I would add here "except for clearing it on start-up". >
I agree > > > An implementation is not required to initialize GPRs to zero during the > > reset procedure. > > I would add here "except for R0, which must be cleared on start-up". > > Otherwise, R0 may not be 0 after all, and that would be a violation of the > assumption above. > Except it should be cleared by software on start-up, the sentence you quoted speaks about hardware not being required to clear them upon reset. Stefan _______________________________________________ OpenRISC mailing list [email protected] http://lists.openrisc.net/listinfo/openrisc
