INT 31H 0a00H: Get Vendor-Specific API Entry Address

                                                    Compatibility: DPMI 0.9+ 
 Expects: AX    0a00H
          DS:SI (or DS:ESI) addr of an ASCIIZ string which identifies the
                DPMI host vendor
 Returns: CF    NC (clear) if successful; else AX = DPMI Error Code
          ES:DI (or ES:EDI) address of API extension API entry address
    Info: If a specific DPMI host vendor supplies an extended API of DPMI
          services, you may use this fn to obtain the address of the host
          code that provides those services.

          Use a FAR CALL to access the extended API.

   Notes: ■ DPMI 1.0+ clients should use INT 2fH 168aH rather than this fn.

          ■ The string passed via ES:(E)DI must match the vendor's name
            exactly; the comparison is case-sensitive.

See Also: DPMI API
          INT 2fH: Multiplex Interrupt
          DOS Functions