🚀 go-pugleaf

In article <1992Sep29.070357.23292@CS.ORST.EDU> @prism.cs.orst.edu writes:
>I need to allocate two 64k buffers in ram from a 16bit device driver. Each of
>the buffers must be completely contained in a segment. They cannot cross a
>segment boundary. Does anyone know of a way to do this?
>
Keith:
How are these buffers to be used. If they are to be used in the
device driver only, then the answer is simple. Here's how:

Allocate a couple of GDT selectors - AllocGDTSelector (CX=1, DL=2DH)
Allocate 64 Kb of memory	   - AllocPhys (DL=18H, DH=1)
Assign the 64 Kb to the selector   - PhysToGDTSelector (CX=65536, DL=2EH)

This can be made smaller/faster by using CX=2 in AllocGDTSelector.
These selectors can be used by the device driver only. If an app
requires access to this memory, then further steps are needed. Also,
the memory will not cross a boundry as the memory will be addressed
as sel:0-65,536.

Hope this helps,
	Colin
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