platform/pc64 will be dropped

[Matthew Dillon]

:I think we need to have something in between:  a CPU specific section of the platform code.
:
:So:  ACPI, APIC, 90% of all headers in platform/pc32/include, stuff like that, all of this is the same between pc32/i386 and pc64/amd64.
:
:Now.  Different are bits like exception handling, etc.  Basically everything in a .s file or containing inline assembler.
:
:So where does us leave this?  We need an intermediate section, which should be "cpu specific platform code".  I think this does make sense.  If somebody has a better idea on how to structure it while avoiding duplication, I'm all ears.  For example, I think having platform specific cpu code seems kind of wrong.

    Something like platform/pccommon/ which the platform/pc32 and
    platform/pc64 Makefile's just add source files from with .PATH
    directives and SRCS+=.

    I dont particularly like the idea because I've considered it before,
    but then again there might not be any other alternative so you are
    definitely a 'go' for doing something like this if you want.

    For sure we dont want to add any more directives to config/<KERNEL>.
    We already have three!  The support directory will simply be common
    code that the primary platform directories include.

    We should have sufficient header file infrastructure in place already
    to access the platform header files (machine/BLAH) from outside the
    platform directories.

    In terms of placement, I dont want to add any new subdirectories to
    /usr/src/sys/.  Even though its a bit polluting of the abstraction,
    the common support director(ies) should probably go in platform/, 
    e.g. platform/pccommon/.

						-Matt