Gives separate methods for initiating and completing a memory access, which will...

Gives separate methods for initiating and completing a memory access, which will be helpful for the merged memory model.

arch/alpha/isa/mem.isa:
    Include methods that allow a memory operation to be split between the part that initiates the access, and the part that completes the access.  In these functions the Mem variable is explicitly declared; in the default execute functions, the Mem variable is still handled through %(op_decl)s.
arch/isa_parser.py:
    Include recording the type of the memory access variable so that it can be used if it needs to be explicitly declared in a template.

    Have memory operands consider themselves neither a source nor a destination to avoid including themselves on the op_src_decl list or the op_dest_decl list.

    Record op_src_decl and op_dest_decl lists to allow for declaring only source or destination operands.  This is needed for the split memory access methods.

--HG--
extra : convert_revision : f674f7a2f747ae40ba8c3a0933b0337c87ee0b6c