INT 94 u - PCM driver - FIND VALID DMA BUFFER IN HUGE MEMORY BLOCK
        SI = 000Bh
        ES:BX -> parameters (see below)
Return: ???
SeeAlso: SI=0003h

Format of parameters:
Offset  Size    Description
 00h    DWORD   -> memory block to contain DMA buffer
 04h    WORD    desired size of DMA buffer

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