AMD64 port

Matthew Dillon dillon at
Sun Jul 15 12:39:33 PDT 2007

:Of course they do not have to correspond, but they should reflect something people can understand.  I do not understand why amd64 bits should be living under "pc32", really.
:  simon

    They wouldn't.  There would be a platform/pc64 for the amd 64 bits
    and a cpu/amd64 or cpu/x86_64 or whatever (I don't know the right name)
    for the cpu-specific bits.

    platform/pc32 and cpu/i386 are hardwired for 32 bit everything,
    particularly the pmap code.  We would never want to try to
    conditionalize it for 32 or 64 bit opration.

    The platforms are named differently from the architectures to avoid 
    the confusion that e.g. FreeBSD has when both platforms AND arcihtectures
    are named the same.  I don't want to call 'pc32' 'i386' when 'i386' is
    also the name of the cpu architecture.

    For an AMD64 port there would be a platform/pc64 and a cpu/amd64 (or
    whatever the appropriate cpu architecture name is for amd64).  FreeBSD
    uses 'amd64'.  Linux has an 'ia64' and also a 'x86_64'.  I'm not sure
    what the relationship is but linux is rather confusing in the way it
    layers architectures.   So are we to a degree, but not as confusing as
    FreeBSD is.


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