Mail Archives: djgpp/1997/04/29/05:02:06
On Mon, 28 Apr 1997, Tom Demmer wrote:
> - Can the DMA buffer be above 1 MB, or _must_ I transfer from/to
> DOS memory?
AFAIK, if it is above 1MB, you will have to use VDS (Virtual DMA
Services) to make sure the DMA buffer is mapped to a certain physical
address. Otherwise, the memory-mapping mechanism will cause the DMA
controller to reference a wrong memory area.
VDS is available with most memory managers (and Windows), but if you
need to run on vanilla DOS (no EMM/QEMM, just CWSDPMI), you don't have
VDS.
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