🚀 go-pugleaf

jason@media-lab.MEDIA.MIT.EDU (Jason A. Kinchen) writes:
>When the documentation says that you have a 4 Gig address space in 386
>Enhanced mode, how's it doing that?  The MS C compiler is only making
>16 bit code and not using the 32 bit segment registers on the 386, so
>what gives?  I guess the Windows Global heap might be using a 32 bit
>register, but how's it getting a 32 bit pointer back into the MS C
>compiled application?

Yes the MS C compiler is making 16-bit code.  Windows all runs in 16-bit
code segments.  But each of those segments can be up to 64K in size, and
you can have LOTS of them.  So you can actually use 4 Gig of address space.

Remember that on the 386 you don't have a segment number, you have a Selector
(or Descriptor).  This number is not a memory reference, but an index
into a table which describes the physical memory address being used.  Thus
a 16:16 pointer can refer to any address in the physical (or virtual)
address space.  You can use all of memory with 16:16 pointers in
selector:offset form.

Mojo

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