On 9/3/07, Patrick McNamara <[EMAIL PROTECTED]> wrote: > Timothy Normand Miller wrote: > > Well, that's not a bad idea. It's also worth pondering architectures > > that have 512 local registers, unifying the scratch space with the > > register file. But that may be too radical. > > > This is pretty common in micro controllers. In the 8 bit AVR series, > there are 32 registers that are the low 32 bytes of the memory space. > Same goes for the 8051 series, though the 8051 also supports a > completely separate external memory space as well. Personally, I think > make perfect sense to not distinguish between the register set, scratch > memory, and I/O space. It reduces the number of instruction types, > reduces the amount of decode logic, etc. > > While we obvious want to make the controller as easily programmable as > possible, efficiency in execution and efficiency in implementation take > precedence in my mind.
Can you give a little more detail on what you're envisioning here? The advantage to a REG-REG architecture is that the instructions are simple and fixed-size. Mapping registers into the memory space has some interesting theoretical advantages, but now you need more logic to distinguish, and you lose some of the benefits of the way a RISC processor is pipelined. -- Timothy Normand Miller http://www.cse.ohio-state.edu/~millerti Open Graphics Project _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
