Have a copyRegs function defined in the ISA that copies registers from one ExecContex...

Have a copyRegs function defined in the ISA that copies registers from one ExecContext to another ExecContext.  This makes it easier for anything that needs to copy architected registers to do so in an ISA independent fashion.

arch/alpha/ev5.cc:
    copyIprs now copies from a source ExecContext to a destination ExecContext.
arch/alpha/registerfile.hh:
    Have ISA specific functions to copy all architected registers from one ExecContext to another.
cpu/cpu_exec_context.cc:
    Call the ISA in order to copy any architected registers.

--HG--
extra : convert_revision : 056cc3b3a9f345535d5a57c6524b114bbd5ae3c8