SbInit ( nIrq, nPort ) ->  lIsSoundcard

   SbInit initializes the VOC-Part of SOUND & VISION.
   Necessary IRQ and Port settings are done with this function,
   as well as testing the DMA-channel. If both checks out fine,
   .T. will be returned and you can start playing...

   You just have to call SbInit once
   (at startup time of your programm, maybe)


   PARAMETERS:

     nIRQ      Hardware-Interrupt, which is used by the SoundBlaster-Card
               valid values are  2, 5 or 7

     nPort     PortAdress of SB-Register
               valid values are 220, 240 or 260

   Default values are IRQ=5 and Port=220

   The default values should work with 95% of all SoundCards, but Murphy
   just told me, that you'll run into somebody who's settings are different,
   so make sure your programm offers different choices...


   RETURN VALUE:

       lIsSoundcard      TRUE  = Fine! SoundBlaster is listening <g>
                         FALSE = Nope, nice try, but it's not working...