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include vdmad.inc VxDcall VDMAD_Request_Buffer |
The VDMAD_Request_Buffer service reserves the DMA buffer for a DMA transfer.
ESI
Specifies the linear address of the actual DMA region.
ECX
Specifies the number of bytes in the DMA region.
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 |
| 5 | DMA_Buffer_Too_Small: Region request is too large for buffer. |
| 6 | DMA_Buffer_In_Use: Buffer already in use. |
EAX, EBX, ESI, Flags