///1TUNE

  Syntax:

          TUNE <filename>

  Explanation:

       TUNE plays PT2/PT3/MYM sound files.

       <filename> of sound file to load and play
       Filename extension determines file type 
       (.PT2, .PT3, or .MYM)

  Notes:

     - Supports AY-3-8910, YM2149, etc.
     - Max  Z80  CPU clock is  about  8 MHz or sound chip  will not
       handle speed.
     - Higher CPU clock  speeds are possible on  Z180 because extra 
       I/O wait states are added during I/O to sound chip.
     - Uses hardware timer support on systems that support a timer.
       Otherwise, a delay loop calibrated to CPU speed is used.
     - Delay loop is calibrated to CPU speed,  but it does not com-
       pensate  for time  variations  in each quark  loop resulting
       from data decompression.
       An average quark processing time is assumed in each loop.
     - Most  sound  files originally  targeted  MSX or  ZX Spectrum 
       which used  1.7897725 MHz and  1.773400 MHz respectively for
       the PSG clock. For best sound playback, PSG should be run at
       approx. this clock rate.

  Author:

       Wayne Warthen (wwarthen@gmail.com)