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include vdmad.inc
 
VxDcall VDMAD_Request_Buffer
 
The VDMAD_Request_Buffer service reserves the DMA buffer for a DMA
transfer.
 
Parameter  Description
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ESI        Specifies the linear address of the actual DMA region.
 
ECX        Specifies the number of bytes in the DMA region.
 
Return Value
 
The carry flag is clear if the service is successful. The EBX register
contains the buffer identifier and the EDX register contains the physical
address of the buffer.
 
Otherwise, the carry flag is set and the AL register contains one of the
following error values:
 
Value  Meaning
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5      DMA_Buffer_Too_Small: region request is too large for buffer
 
6      DMA_Buffer_In_Use: buffer already in use
 
Uses
 
EAX, EBX, ESI, Flags
 
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