AMD64 port

[Matthew Dillon]

:Matt,
:
:under platform/pc32/, what do you mean to have a i386 folder and all
:the source files in the folder, the are cpu-specific codes under
:platform?
:
:Yonghong

    Well, the name 'i386' was inherited from prior directory layouts.
    Most of the code in there is platform AND cpu-specific.  Most of the 
    platform-specific assembly code is in there too.  For example,
    copyin().

						-Matt