18. Get Vendor Specific API Entry Point

Some DOS extenders provide extensions to the standard set of DPMI calls. This call is used to obtain an address which must be called to use the extensions. The caller points DS:(E)SI to a null terminated string that specifies the vendor name or some other unique identifier to obtain the specific extension entry point.

To Call

     AX = 0A00h
     DS:(E)SI = Pointer to null terminated string

Returns

     If function was successful:
     Carry flag is clear
     ES:(E)DI = Extended API entry point
     DS, FS, GS, EAX, EBX, ECX, EDX, ESI, and EBP may be modified

     If function was not successful:
     Carry flag is set

Programmer's Notes

• Execute a far call to call the API entry point.
• All extended API parameters are specified by the vendor.
• The string comparison used to return the API entry point is case sensitive.